title: Self-harm

text: Deliberate self-harm is especially prevalent in prison populations. A proposed explanation for this is that prisons are often violent places, and prisoners who wish to avoid physical confrontations may resort to self-harm as a ruse, either to convince other prisoners that they are dangerously insane and resilient to pain or to obtain protection from the prison authorities. Self-harm also occurs frequently in inmates who are placed in solitary confinement.


title: Self-harm

text: The Maya priesthood performed auto-sacrifice by cutting and piercing their bodies in order to draw blood. A reference to the priests of Baal "cutting themselves with blades until blood flowed" can be found in the Hebrew Bible. However, in Judaism, such self-harm is forbidden under Mosaic law. It occurred in ancient Canaanite mourning rituals, as described in the Ras Shamra tablets.


title: Self-harm

text: Self-harm is practised in Hinduism by the ascetics known as "sadhu"s. In Catholicism it is known as mortification of the flesh. Some branches of Islam mark the Day of Ashura, the commemoration of the martyrdom of Imam Hussein, with a ritual of self-flagellation, using chains and swords.


title: Self-harm

text: Dueling scars such as those acquired through academic fencing at certain traditional German universities are an early example of scarification in European society. Sometimes, students who did not fence would scar themselves with razors in imitation.


title: Self-harm

text: Constance Lytton, a prominent suffragette, used a stint in Holloway Prison during March 1909 to mutilate her body. Her plan was to carve 'Votes for Women' from her breast to her cheek, so that it would always be visible. But after completing the "V" on her breast and ribs she requested sterile dressings to avoid blood poisoning, and her plan was aborted by the authorities. She wrote of this in her memoir "Prisons and Prisoners".


title: Self-harm

text: Kikuyu girls cut each other's vulvas in the 1950s as a symbol of defiance, in the context of the campaign against female genital mutilation in colonial Kenya. The movement came to be known as "Ngaitana" ("I will circumcise myself"), because to avoid naming their friends the girls said they had cut themselves. Historian Lynn Thomas described the episode as significant in the history of FGM because it made clear that its victims were also its perpetrators.


title: Self-harm

text: The term "self-mutilation" occurred in a study by L. E. Emerson in 1913 where he considered self-cutting a symbolic substitution for masturbation. The term reappeared in an article in 1935 and a book in 1938 when Karl Menninger refined his conceptual definitions of self-mutilation. His study on self-destructiveness differentiated between suicidal behaviors and self-mutilation. For Menninger, self-mutilation was a non-fatal expression of an attenuated death wish and thus coined the term "partial suicide". He began a classification system of six types:


title: Self-harm

text: Pao (1969) differentiated between "delicate" (low lethality) and "coarse" (high lethality) self-mutilators who cut. The "delicate" cutters were young, multiple episodic of superficial cuts and generally had borderline personality disorder diagnosis. The "coarse" cutters were older and generally psychotic. Ross and McKay (1979) categorized self-mutilators into 9 groups: "cutting", "biting", "abrading", "severing", "inserting", "burning", "ingesting or inhaling", "hitting", and "constricting".


title: Self-harm

text: Walsh and Rosen (1988) created four categories numbered by Roman numerals I–IV, defining "Self-mutilation" as rows II, III and IV.


title: Self-harm

text: Favazza and Rosenthal (1993) reviewed hundreds of studies and divided self-mutilation into two categories: "culturally sanctioned self-mutilation" and "deviant self-mutilation". Favazza also created two subcategories of sanctioned self-mutilations; "rituals" and "practices". The "rituals" are mutilations repeated generationally and "reflect the traditions, symbolism, and beliefs of a society" (p. 226). "Practices" are historically transient and cosmetic such as piercing of earlobes, nose, eyebrows as well as male circumcision (for non-Jews) while "Deviant self-mutilation" is equivalent to self-harm.


title: Self-harm

text: There are many movements among the general self-harm community to make self-harm itself and treatment better known to mental health professionals, as well as the general public. For example, March 1 is designated as Self-injury Awareness Day (SIAD) around the world. On this day, some people choose to be more open about their own self-harm, and awareness organizations make special efforts to raise awareness about self-harm.


title: Self-harm

text: Self-harm in non-human mammals is a well-established but not widely known phenomenon. Its study under zoo or laboratory conditions could lead to a better understanding of self-harm in human patients.


title: Self-harm

text: Zoo or laboratory rearing and isolation are important factors leading to increased susceptibility to self-harm in higher mammals, e.g., macaque monkeys. Non-primate mammals are also known to mutilate themselves under laboratory conditions after administration of drugs. For example, pemoline, clonidine, amphetamine, and very high (toxic) doses of caffeine or theophylline are known to precipitate self-harm in lab animals.


title: Self-harm

text: In dogs, canine obsessive-compulsive disorder can lead to self-inflicted injuries, for example canine lick granuloma. Captive birds are sometimes known to engage in feather-plucking, causing damage to feathers that can range from feather shredding to the removal of most or all feathers within the bird's reach, or even the mutilation of skin or muscle tissue.


title: Self-harm

text: One known as "barbering" involves a mouse obsessively grooming the whiskers and facial fur off of themselves and cage-mates.


title: Adventure Time: Distant Lands

text: Adventure Time: Distant Lands is an American animated limited series based on the animated television series "Adventure Time", which was created by Pendleton Ward and originally aired on Cartoon Network from 2010 to 2018. "Distant Lands", which comprises four hour-long streaming television specials, was produced by Frederator Studios and Cartoon Network Studios; the first special was released on HBO Max on June 25, 2020. The rest of the specials were released on November 19, 2020, May 20, 2021, and September 2, 2021.


title: Adventure Time: Distant Lands

text: The series at large follows the adventures of Finn (a human boy) and his best friend and adoptive brother Jake, a dog with magical powers to change shape and size at will. Finn and Jake live in the post-apocalyptic Land of Ooo, where they interact with the series' other main characters, including Princess Bubblegum, Marceline the Vampire Queen, and BMO. "Distant Lands" focuses on new and returning characters in previously unexplored areas of the "Adventure Time" universe.


title: Adventure Time: Distant Lands

text: The series follows the adventures of Finn the Human (a boy), and his best friend and brother Jake, a dog with magical powers to change shape and size at will. Finn and Jake live in the post-apocalyptic Land of Ooo, where they interact with the other major characters, such as Princess Bubblegum, Marceline the Vampire Queen, and BMO. Common storylines revolve around Finn and Jake going on the titular adventures, discovering strange creatures, and battling monsters to help others.


title: Adventure Time: Distant Lands

text: On September 29, 2016, Cartoon Network officially announced that "Adventure Time" would end. Storyline writing for the initial series ended in mid-November 2016, and the show's final script was pitched to storyboarders on November 28. Voice recording for the initial series ended on January 31, 2017. Several of the show's crew members were then hired for Cartoon Network's "Summer Camp Island", created by "Adventure Time" storyline writer Julia Pott. The "Adventure Time" finale, "Come Along with Me", aired on September 3, 2018, to a largely positive reception.


title: Adventure Time: Distant Lands

text: The "Adventure Time: Distant Lands" specials, like the original series, were a co-production between Frederator Studios and Cartoon Network Studios, but unlike the previous seasons, the specials debuted on HBO Max, the video on demand service from WarnerMedia Entertainment. The "Distant Lands" specials have their origin during the production of the show's tenth season. Because the show had had success with specials and miniseries in the past (such as "Stakes" and "Elements"), the writers started to pitch a number of stories that could be told in longer formats. Two big ideas that emerged during this time were storylines focusing on BMO in space, and another focusing on Marceline and Bubblegum's relationship. Production for these longer stories, however, was halted when the series was cancelled. Later, when HBO and Cartoon Network began to revive the series for the HBO Max streaming service, the "Adventure Time" writers went back to these old ideas, and in time they generated the four "Distant Lands" specials.


title: Adventure Time: Distant Lands

text: Many of the cast from the original series returned for the specials, including Jeremy Shada as Finn the Human, John DiMaggio as Jake the Dog, Niki Yang as BMO, Hynden Walch as Princess Bubblegum, Olivia Olson as Marceline the Vampire Queen, and Steve Little as Peppermint Butler. New characters included Glory Curda as Y5 and Simone Giertz as CGO; both of them were already fans of "Adventure Time" before joining the cast. Guest voices include returning cast members Maria Bamford, Ashly Burch, and Ron Perlman, as well as Randall Park, Stephen Root, John Hodgman, David Bradley, Chris Fleming, Isabelle Fuhrman, Andy Daly, Ron Lynch, Tom Scharpling, Bill Hader, Julia Butters, Patti Harrison, Toks Olagundoye, Edi Patterson, Bex Taylor-Klaus, Dana Snyder, Duncan Trussell, SungWon Cho, and Anthony Head.


title: Adventure Time: Distant Lands

text: Longtime "Adventure Time" executive producer Adam Muto returned to oversee the production of the specials, with Jack Pendarvis, Anthony Burch, Jesse Moynihan, Christina Catucci, Charley Feldman, and Kate Tsang serving as part of the writing staff. Storyboard artists who worked on these specials include (but are not limited to): Ashlyn Anstee, Jim Campbell, Iggy Craig, Megan Fisher, Laura Knetzger, Hanna K. Nyström, Maya Petersen, Anna Syvertsson, Mickey Quinn, and Serena Wu. Miki Brewster served as supervising director for the specials. From June to September 2019, Jenny Goldberg briefly served as art director for the specials, after which original series art director Sandra Lee served in that role. On April 21, 2021, HBO Max announced that the airing sequence of "Wizard City" and "Together Again" would be switched, with the latter airing before the former. After this announcement, Adam Muto explained that, initially, only three specials had been ordered, but that "Wizard City" was added on later and was the actual last special to be made.


title: Adventure Time: Distant Lands

text: The end credits of the final special "Together Again" feature a dedication to four deceased members of the show's cast and crew: Polly Lou Livingston, Miguel Ferrer, Michel Lyman, and Maureen Mlynarczyk. Livingston and Ferrer had provided the voices for Tree Trunks and Death, respectively. Lyman and Mlynarczyk, on the other hand, were both sheet timers on the original series and Emmy Awards winners.


title: Adventure Time: Distant Lands

text: Reception to "BMO" has been mostly positive. Rollin Bishop of "Comic Book" wrote that the special's biggest strength is that BMO is "the most innocent and also the most prone to misadventure" compared to the other "Adventure Time" characters, which made the special itself a "solid watch from start to finish." Others called "BMO" a "blend of dream logic, comedy, and surreal heroism". Other reviewers praised the show for recapturing the magic of the original show, with Petrana Radulovic of Polygon arguing that it shared the same "melancholy feeling" as its parent series. Other reviews were not as positive. Grace Z. Li of "Vulture" called the special "disappointing" even while praising the performance of BMO. Dave Trumbore of "Collider" singled out the pacing for critique, writing that the special seemed rushed "when it comes to story beats and character development."


title: Adventure Time: Distant Lands

text: A number of reviewers commented on the episode's social commentary. The voice-actress for Y5, Glory Curda, argued that Y5's story has a lot of context and is representative of coming out into one's identity, defining the self with whatever terms are comfortable for a person. Alexander Sowa of "CBR" argued that Hugo is a futurist akin to Elon Musk or Steve Jobs, whose characterization is "a clear satire of modern-day corporations and capitalists." Sowa also argued that contra Hugo—a capitalist and colonist who "destroys the world around him"—Y5 can be seen as a fighter for equity who pushes for a new form of social organization that is fairer to the inhabitants of the Drift. Joe Matar of Den of Geek noted similar themes, saying that the story is about those living in Drift realizing that "their Elon Musk-esque tech capitalist overlord [Hugo] is destroying their world," which forces them to come together and rely on one another. Robert Lloyd of the "Los Angeles Times" likewise noted that the special hints at social commentary toward the end, referring to the destruction of Earth, the nature of resource management, the importance of cooperation, and "the way that certain human billionaires look at space as an escape pod."


title: Adventure Time: Distant Lands

text: Writing for "The A.V. Club", William Hughes gave this episode an A, calling it "fan service at its finest" with "plenty of the usual lovely "Adventure Time" touches". Additionally, Rebecca Long also gave a positive review of the episode for "Polygon". She wrote that the episode gives fans the "emotional payoff and answers" they have been yearning for and that the special uses the plot to explore Marceline's childhood trauma, her romantic history with Bubblegum, how the two are interconnected, and fills in gaps about her past. Long also stated that while the special is not "as offbeat" as "BMO", it is heavier in terms of emotional weight and plot, and making clear that "romantic subtext" in the original show has "always been straight-up text." At the same time, she states that not all interactions between Bubblegum and Marceline are loving, that the special has flaws due to a conventional structure and storytelling, even with some "inconsistencies in Princess Bubblegum's character design," but is still heartfelt and effective, complete with new music, with Marceline and Bubblegum having "a shared future that feels real." The episode was nominated for a GLAAD Media Award, taking place in 2021, for Outstanding Kids & Family Programming, praised for using the plot to explore Marceline's childhood trauma, her romantic history with Bubblegum, how the two are interconnected, and for giving Marceline and Princess Bubblegum a "shared future that feels real."


title: Adventure Time: Distant Lands

text: Rosie Knight of IGN wrote that the special was a "perfect example of why ["Adventure Time"] made such a huge impact." Knight contended that the special's strongest asset was "how accessible it is to new viewers", given that both "hardcore fans" as well as new viewers who had little understanding of the characters could still come together and "enjoy this fantastical romp about aging, falling in love, and settling down". Knight further complimented the special for its message that Marceline's power comes from her love of Bubblegum. Knight also applauded the "Monster", which she argued is as iconic as "I'm Just Your Problem" (from season three's "What Was Missing") and "Everything Stays" (from "Stakes"). Knight concluded her review by noting that while the special could be seen as mere "fan service", it is "fan service of the highest order", "a wonderful animated episode", and "a fitting addition to "Adventure Time"s legacy." Petrana Radulovic of Polygon argued that 2020, when it came to all-ages animation, was a "glorious gay celebration that was unheard of just five years ago," the development of Marceline and Bubblegum's relationship in the "Obsidian" episode. She specifically said that Obsidian was a "perfect end to this big gay year in animation," while noting that there is still work to do going forward.


title: Adventure Time: Distant Lands

text: Alexander Sowa of CBR described the episode as "a story about time," including various flashbacks, and is a story about immortals, with Sowa saying that Bubblegum and Marceline will "remain young at heart" even as their human companions die. Sean Cubillas had a similar description. He stated that the episode had "plenty of emotion and heart," adding that the episode showed that Marceline has grown up from what she was like in the original series, how Bonnie and Marcy met one another, and how they broke up in the past. At the same time, Princess Weekes of "The Mary Sue", before the episode aired, said she found it reassuring because for queer representation "it is important to acknowledge that loving someone doesn't fix emotional issues or personality flaws." At the close of 2020, "The New York Times" named "Obsidian" one of "best TV episodes" of the year, calling it "the best excuse for [HBO Max's] existence."


title: Adventure Time: Distant Lands

text: The episode was received positively. Rollin Bishop of "ComicBook" described it as a whirlwind "tour through fantastical worlds," with jokes, callbacks, and brotherly love. Bishop also called it an "emotional roller coaster" and compared it to the previous special "Obsidian." Caroline Gao of "Den of Geek" described the episode as well-adjusted to the long format with a dark tone. Gao also compared the relationship between Finn and Jake in the episode, to the relationship between Princess Bubblegum and Marceline in "Obsidian," concluding that while it is not as profound as the series finale "Come Along With Me," it "fits into the middle of an Adventure Time season" rather than a bonus episode that follows the series finale. Eric Kohn of IndieWire argued that the episode is "endearing, nice-to-have fan service" that isn't as ingenious as the show, but there is plenty to enjoy, with the reappearance various characters, and said it has a touching moment that resembles Pixar's movie, "Soul". Petrana Radulovic of Polygon noted that while "BMO" and "Obsidian" specials have showcased emotions and tried to answer deeper questions, this special begins with a quest, then turns into "something poignant," and becomes an "emotional rollercoaster." Radulovic said that other than the character reappearances, the special is visually gorgeous," and serves almost a metaphor for the journey that Finn and Jake undertake in the show itself, calling the episode a "beautiful, powerful, poignant ending" which captures the emotional depth of "Adventure Time" itself. Reuben Baron of CBR called the special "pretty much perfect," with the biggest adventure in the episode as death, with the Jake and Finn going on an "epic heroic adventure," willing to give each other's lives so they can reincarnate. He also called the special a great "ending to Finn and Jake's story."


title: Adventure Time: Distant Lands

text: Compared to previous episodes, critical reception to "Wizard City" was more mixed. Kyle Logan of "Cultured Vultures" felt that the special was tonally disconnected from the original series, and he argued that while "Wizard City" is ostensibly focused on Peppermint Butler, the special fails to portray the character in a way that made him a fan-favorite in the first place. Logan ultimately argued that the special fails to deliver on its story potential. Alejandra Bodden of Bleeding Cool was surprised by the number of deaths in the episode; she wrote that while she enjoyed Peps, she found his situation and the special's plot to be "kind of a fucked up." Although she felt that "Wizard City" was the weakest out of the four "Distant Lands" episodes, Bodden wrote that it was still an enjoyable experience overall. Writing for "Bubble Blabber", David Kaldor wrote that the episode was a strange conclusion to the "Distant Lands" specials. Kaldor felt that, in terms of writing, the special was "pretty adequate", but he felt that it lacked the emotional punch of the previous three episodes.


title: Adventure Time: Distant Lands

text: Reuben Baron of "Comic Book Resources" contrasted the episode to the sixth-season episode "Gold Stars" and the ninth-season episode "Whispers," given similar themes in all three; despite the runtime of the latter two episode being around 20 minutes, Baron felt that they were more interesting than the 40-minutes "Wizard City", which he argued was derivative. Autumn Wright of "We Got This Covered" wrote that "Wizard City" was defined by an ethos of "queer living, not just queer moments": some non-human characters are more unconventional in gender. A side character named Blaine, for instance, is one-eyed and sometimes regarded as a boy; he sometimes wears skirt and is addressed with they/them. Peps and Cadebra are roommates despite having different genders, and characters wear uniforms with pants, shorts or skirts. Wright commented that "Wizard City" is a step ahead compared to the representation seen in "The Owl House" and "She-Ra and the Princesses of Power", even though the latter two "sport headline-grabbing relationships."


title: Adventure Time: Distant Lands

text: The album, "BMO's Mixtape (Gilligan Moss Mix)" was released on September 18, 2020. It is not a soundtrack of the "BMO" special, but features remixed music from the original series, as well as a mix of the song "Eternity With You" from the "Obsidian" special. The album is mixed by the American musical duo Gilligan Moss.


title: Adventure Time: Distant Lands

text: The soundtrack to "Obsidian" was released on November 20, 2020. The album also features a promotional cover of the song "Monster" sung by American singer-songwriter King Princess. This track was released as a single on November 13, 2020.


title: Omega-3 fatty acid

text: Omega−3 fatty acids, also called Omega-3 oils, ω−3 fatty acids or "n"−3 fatty acids, are polyunsaturated fatty acids (PUFAs) characterized by the presence of a double bond, three atoms away from the terminal methyl group in their chemical structure. They are widely distributed in nature, being important constituents of animal lipid metabolism, and they play an important role in the human diet and in human physiology. The three types of omega−3 fatty acids involved in human physiology are α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA can be found in plants, while DHA and EPA are found in algae and fish. Marine algae and phytoplankton are primary sources of omega−3 fatty acids. DHA and EPA accumulate in fish that eat these algae. Common sources of plant oils containing ALA include walnuts, edible seeds, and flaxseeds as well as hempseed oil, while sources of EPA and DHA include fish and fish oils, and algae oil.


title: Omega-3 fatty acid

text: Mammals are unable to synthesize the essential omega−3 fatty acid ALA and can only obtain it through diet. However, they can use ALA, when available, to form EPA and DHA, by creating additional double bonds along its carbon chain (desaturation) and extending it (elongation). Namely, ALA (18 carbons and 3 double bonds) is used to make EPA (20 carbons and 5 double bonds), which is then used to make DHA (22 carbons and 6 double bonds). The ability to make the longer-chain omega−3 fatty acids from ALA may be impaired in aging. In foods exposed to air, unsaturated fatty acids are vulnerable to oxidation and rancidity.


title: Omega-3 fatty acid

text: There is no high-quality evidence that dietary supplementation with omega−3 fatty acids reduces the risk of cancer or cardiovascular disease. Furthermore, fish oil supplement studies have failed to support claims of preventing heart attacks or strokes or any vascular disease outcomes.


title: Omega-3 fatty acid

text: In 1929, George and Mildred Burr discovered that fatty acids were critical to health. If fatty acids were absent from the diet, a life-threatening deficiency syndrome ensued. The Burrs coined the phrase "essential fatty acids". Since then, researchers have shown a growing interest in unsaturated essential fatty acids as they form the framework for the organism’s cell membranes. Subsequently, awareness of the health benefits of essential fatty acids has dramatically increased since the 1980s.


title: Omega-3 fatty acid

text: On September 8, 2004, the U.S. Food and Drug Administration gave "qualified health claim" status to EPA and DHA omega−3 fatty acids, stating, "supportive but not conclusive research shows that consumption of EPA and DHA [omega−3] fatty acids may reduce the risk of coronary heart disease". This updated and modified their health risk advice letter of 2001 (see below).


title: Omega-3 fatty acid

text: The Canadian Food Inspection Agency has recognized the importance of DHA omega−3 and permits the following claim for DHA: "DHA, an omega−3 fatty acid, supports the normal physical development of the brain, eyes, and nerves primarily in children under two years of age."


title: Omega-3 fatty acid

text: Historically, whole food diets contained sufficient amounts of omega−3, but because omega−3 is readily oxidized, the trend to shelf-stable, processed foods has led to a deficiency in omega−3 in manufactured foods.


title: Omega-3 fatty acid

text: The terms "ω−3 ("omega−3") fatty acid" and "n−3 fatty acid" are derived from the nomenclature of organic chemistry. One way in which an unsaturated fatty acid is named is determined by the location, in its carbon chain, of the double bond which is closest to the methyl end of the molecule. In general terminology, "n" (or ω) represents the locant of the methyl end of the molecule, while the number "n−x" (or ω−"x") refers to the locant of its nearest double bond. Thus, in omega"−"3 fatty acids in particular, there is a double bond located at the carbon numbered 3, starting from the methyl end of the fatty acid chain. This classification scheme is useful since most chemical changes occur at the carboxyl end of the molecule, while the methyl group and its nearest double bond are unchanged in most chemical or enzymatic reactions.


title: Omega-3 fatty acid

text: In the expressions "n−x" or ω−"x", the symbol is a minus sign rather than a hyphen (or dash), although it is never read as such. Also, the symbol "n" (or ω) represents the locant of the methyl end, counted from the carboxyl end of the fatty acid carbon chain. For instance, in an omega−3 fatty acid with 18 carbon atoms (see illustration), where the methyl end is at location 18 from the carboxyl end, "n" (or ω) represents the number 18, and the notation n−3 (or ω−3) represents the subtraction 18−3 = 15, where 15 is the locant of the double bond which is closest to the methyl end, counted from the carboxyl end of the chain.


title: Omega-3 fatty acid

text: Although "n" and ω (omega) are synonymous, the IUPAC recommends that "n" be used to identify the highest carbon number of a fatty acid. Nevertheless, the more common name – omega"−"3 fatty acid – is used in both the lay media and scientific literature.


title: Omega-3 fatty acid

text: For example, α-linolenic acid (ALA; illustration) is an 18-carbon chain having three double bonds, the first being located at the third carbon from the methyl end of the fatty acid chain. Hence, it is an omega"−"3 fatty acid. Counting from the other end of the chain, that is the carboxyl end, the three double bonds are located at carbons 9, 12, and 15. These three locants are typically indicated as Δ9c, Δ12c, Δ15c, or cisΔ, cisΔ, cisΔ, or cis-cis-cis-Δ, where "c" or "cis" means that the double bonds have a "cis" configuration.


title: Omega-3 fatty acid

text: α-Linolenic acid is polyunsaturated (containing more than one double bond) and is also described by a lipid number, 18:3, meaning that there are 18 carbon atoms and 3 double bonds.


title: Omega-3 fatty acid

text: An omega−3 fatty acid is a fatty acid with multiple double bonds, where the first double bond is between the third and fourth carbon atoms from the end of the carbon atom chain. "Short-chain" omega−3 fatty acids have a chain of 18 carbon atoms or less, while "long-chain" omega−3 fatty acids have a chain of 20 or more.


title: Omega-3 fatty acid

text: Three omega−3 fatty acids are important in human physiology, α-linolenic acid (18:3, "n"-3; ALA), eicosapentaenoic acid (20:5, "n"-3; EPA), and docosahexaenoic acid (22:6, "n"-3; DHA). These three polyunsaturates have either 3, 5, or 6 double bonds in a carbon chain of 18, 20, or 22 carbon atoms, respectively. As with most naturally-produced fatty acids, all double bonds are in the "cis"-configuration, in other words, the two hydrogen atoms are on the same side of the double bond; and the double bonds are interrupted by methylene bridges (--), so that there are two single bonds between each pair of adjacent double bonds.


title: Omega-3 fatty acid

text: Omega−3 fatty acids occur naturally in two forms, triglycerides and phospholipids. In the triglycerides, they, together with other fatty acids, are bonded to glycerol; three fatty acids are attached to glycerol. Phospholipid omega−3 is composed of two fatty acids attached to a phosphate group via glycerol.


title: Omega-3 fatty acid

text: The triglycerides can be converted to the free fatty acid or to methyl or ethyl esters, and the individual esters of omega−3 fatty acids are available.


title: Omega-3 fatty acid

text: DHA in the form of lysophosphatidylcholine is transported into the brain by a membrane transport protein, MFSD2A, which is exclusively expressed in the endothelium of the blood–brain barrier.


title: Omega-3 fatty acid

text: The 'essential' fatty acids were given their name when researchers found that they are essential to normal growth in young children and animals. The omega−3 fatty acid DHA, also known as docosahexaenoic acid, is found in high abundance in the human brain. It is produced by a desaturation process, but humans lack the desaturase enzyme, which acts to insert double bonds at the ω and ω position. Therefore, the ω and ω polyunsaturated fatty acids cannot be synthesized, are appropriately called essential fatty acids, and must be obtained from the diet.


title: Omega-3 fatty acid

text: In 1964, it was discovered that enzymes found in sheep tissues convert omega−6 arachidonic acid into the inflammatory agent, prostaglandin E, which is involved in the immune response of traumatized and infected tissues. By 1979, eicosanoids were further identified, including thromboxanes, prostacyclins, and leukotrienes. The eicosanoids typically have a short period of activity in the body, starting with synthesis from fatty acids and ending with metabolism by enzymes. If the rate of synthesis exceeds the rate of metabolism, the excess eicosanoids may have deleterious effects. Researchers found that certain omega−3 fatty acids are also converted into eicosanoids and docosanoids, but at a slower rate. If both omega−3 and omega−6 fatty acids are present, they will "compete" to be transformed, so the ratio of long-chain omega−3:omega−6 fatty acids directly affects the type of eicosanoids that are produced.


title: Omega-3 fatty acid

text: Humans can convert short-chain omega−3 fatty acids to long-chain forms (EPA, DHA) with an efficiency below 5%. The omega−3 conversion efficiency is greater in women than in men, but less studied. Higher ALA and DHA values found in plasma phospholipids of women may be due to the higher activity of desaturases, especially that of delta-6-desaturase.


title: Omega-3 fatty acid

text: These conversions occur competitively with omega−6 fatty acids, which are essential closely related chemical analogues that are derived from linoleic acid. They both utilize the same desaturase and elongase proteins in order to synthesize inflammatory regulatory proteins. The products of both pathways are vital for growth making a balanced diet of omega−3 and omega−6 important to an individual's health. A balanced intake ratio of 1:1 was believed to be ideal in order for proteins to be able to synthesize both pathways sufficiently, but this has been controversial as of recent research.


title: Omega-3 fatty acid

text: The conversion of ALA to EPA and further to DHA in humans has been reported to be limited, but varies with individuals. Women have higher ALA-to-DHA conversion efficiency than men, which is presumed to be due to the lower rate of use of dietary ALA for beta-oxidation. One preliminary study showed that EPA can be increased by lowering the amount of dietary linoleic acid, and DHA can be increased by elevating intake of dietary ALA.


title: Omega-3 fatty acid

text: Human diet has changed rapidly in recent centuries resulting in a reported increased diet of omega−6 in comparison to omega−3. The rapid evolution of human diet away from a 1:1 omega−3 and omega−6 ratio, such as during the Neolithic Agricultural Revolution, has presumably been too fast for humans to have adapted to biological profiles adept at balancing omega−3 and omega−6 ratios of 1:1. This is commonly believed to be the reason why modern diets are correlated with many inflammatory disorders. While omega−3 polyunsaturated fatty acids may be beneficial in preventing heart disease in humans, the level of omega−6 polyunsaturated fatty acids (and, therefore, the ratio) does not matter.


title: Omega-3 fatty acid

text: Both omega−6 and omega−3 fatty acids are essential: humans must consume them in their diet. Omega−6 and omega−3 eighteen-carbon polyunsaturated fatty acids compete for the same metabolic enzymes, thus the omega−6:omega−3 ratio of ingested fatty acids has significant influence on the ratio and rate of production of eicosanoids, a group of hormones intimately involved in the body's inflammatory and homeostatic processes, which include the prostaglandins, leukotrienes, and thromboxanes, among others. Altering this ratio can change the body's metabolic and inflammatory state.


title: Omega-3 fatty acid

text: Metabolites of omega−6 are more inflammatory (esp. arachidonic acid) than those of omega−3. However in terms of heart health omega-6 fatty acids less harmful than they are presumed to be. A meta-analysis of six randomized trials found that replacing saturated fat with omega-6 fats reduced the risk of coronary events by 24%.


title: Omega-3 fatty acid

text: A healthy ratio of omega-6 to omega-3 is needed; healthy ratios, according to some authors, range from 1:1 to 1:4. Other authors believe that a ratio of 4:1 (4 times as much omega−6 as omega−3) is already healthy.


title: Omega-3 fatty acid

text: Typical Western diets provide ratios of between 10:1 and 30:1 (i.e., dramatically higher levels of omega−6 than omega−3). The ratios of omega−6 to omega−3 fatty acids in some common vegetable oils are: canola 2:1, hemp 2–3:1, soybean 7:1, olive 3–13:1, sunflower (no omega−3), flax 1:3, cottonseed (almost no omega−3), peanut (no omega−3), grapeseed oil (almost no omega−3) and corn oil 46:1.


title: Omega-3 fatty acid

text: In the United States, the Institute of Medicine publishes a system of Dietary Reference Intakes, which includes Recommended Dietary Allowances (RDAs) for individual nutrients, and Acceptable Macronutrient Distribution Ranges (AMDRs) for certain groups of nutrients, such as fats. When there is insufficient evidence to determine an RDA, the institute may publish an Adequate Intake (AI) instead, which has a similar meaning but is less certain. The AI for α-linolenic acid is 1.6 grams/day for men and 1.1 grams/day for women, while the AMDR is 0.6% to 1.2% of total energy. Because the physiological potency of EPA and DHA is much greater than that of ALA, it is not possible to estimate one AMDR for all omega−3 fatty acids. Approximately 10 percent of the AMDR can be consumed as EPA and/or DHA. The Institute of Medicine has not established a RDA or AI for EPA, DHA or the combination, so there is no Daily Value (DVs are derived from RDAs), no labeling of foods or supplements as providing a DV percentage of these fatty acids per serving, and no labeling a food or supplement as an excellent source, or "High in..." As for safety, there was insufficient evidence as of 2005 to set an upper tolerable limit for omega−3 fatty acids, although the FDA has advised that adults can safely consume up to a total of 3 grams per day of combined DHA and EPA, with no more than 2 g from dietary supplements.


title: Omega-3 fatty acid

text: The American Heart Association (AHA) has made recommendations for EPA and DHA due to their cardiovascular benefits: individuals with no history of coronary heart disease or myocardial infarction should consume oily fish two times per week; and "Treatment is reasonable" for those having been diagnosed with coronary heart disease. For the latter the AHA does not recommend a specific amount of EPA + DHA, although it notes that most trials were at or close to 1000 mg/day. The benefit appears to be on the order of a 9% decrease in relative risk. The European Food Safety Authority (EFSA) approved a claim "EPA and DHA contributes to the normal function of the heart" for products that contain at least 250 mg EPA + DHA. The report did not address the issue of people with pre-existing heart disease. The World Health Organization recommends regular fish consumption (1-2 servings per week, equivalent to 200 to 500 mg/day EPA + DHA) as protective against coronary heart disease and ischaemic stroke.


title: Omega-3 fatty acid

text: Heavy metal poisoning from consuming fish oil supplements is highly unlikely, because heavy metals (mercury, lead, nickel, arsenic, and cadmium) selectively bind with protein in the fish flesh rather than accumulate in the oil.


title: Omega-3 fatty acid

text: However, other contaminants (PCBs, furans, dioxins, and PBDEs) might be found, especially in less-refined fish oil supplements.


title: Omega-3 fatty acid

text: Throughout their history, the Council for Responsible Nutrition and the World Health Organization have published acceptability standards regarding contaminants in fish oil. The most stringent current standard is the International Fish Oils Standard. Fish oils that are molecularly distilled under vacuum typically make this highest-grade; levels of contaminants are stated in parts per billion per trillion.


title: Omega-3 fatty acid

text: A 2022 study found that a number of products on the market used oxidised oils, with the rancidity often masked by flavourings. Another study found that 2015 an average of 20% of products had excess oxidation. Whether rancid fish oil is harmful remains unclear. Some studies show that highly oxidised fish oil can have negative impact on cholesterol levels. Animal testing showed that high doses have toxic effects. Furthermore, rancid oil is likely to be less effective than fresh fish oil.


title: Omega-3 fatty acid

text: The most widely available dietary source of EPA and DHA is oily fish, such as salmon, herring, mackerel, anchovies, and sardines. Oils from these fishes have around seven times as much omega−3 as omega−6. Other oily fish, such as tuna, also contain "n"-3 in somewhat lesser amounts. Although fish are a dietary source of omega−3 fatty acids, fish do not synthesize omega−3 fatty acids, but rather obtain them via their food supply, including algae or plankton. In order for farmed marine fish to have amounts of EPA and DHA comparable to those of wild-caught fish, their feed must be supplemented with EPA and DHA, most commonly in the form of fish oil. For this reason, 81% of the global fish oil supply in 2009 was consumed by aquaculture.


title: Omega-3 fatty acid

text: Marine and freshwater fish oil vary in content of arachidonic acid, EPA and DHA. They also differ in their effects on organ lipids.


title: Omega-3 fatty acid

text: Not all forms of fish oil may be equally digestible. Of four studies that compare bioavailability of the glyceryl ester form of fish oil vs. the ethyl ester form, two have concluded the natural glyceryl ester form is better, and the other two studies did not find a significant difference. No studies have shown the ethyl ester form to be superior, although it is cheaper to manufacture.


title: Omega-3 fatty acid

text: Krill oil is a source of omega−3 fatty acids. The effect of krill oil, at a lower dose of EPA + DHA (62.8%), was demonstrated to be similar to that of fish oil on blood lipid levels and markers of inflammation in healthy humans. While not an endangered species, krill are a mainstay of the diets of many ocean-based species including whales, causing environmental and scientific concerns about their sustainability.


title: Omega-3 fatty acid

text: Preliminary studies appear to indicate that the DHA and EPA omega−3 fatty acids found in krill oil may be more bio-available than in fish oil. Additionally, krill oil contains astaxanthin, a marine-source keto-carotenoid antioxidant that may act synergistically with EPA and DHA.


title: Omega-3 fatty acid

text: Linseed (or flaxseed) ("Linum usitatissimum") and its oil are perhaps the most widely available botanical source of the omega−3 fatty acid ALA. Flaxseed oil consists of approximately 55% ALA, which makes it six times richer than most fish oils in omega−3 fatty acids. A portion of this is converted by the body to EPA and DHA, though the actual converted percentage may differ between men and women.


title: Omega-3 fatty acid

text: In 2013 Rothamsted Research in the UK reported they had developed a genetically modified form of the plant Camelina that produced EPA and DHA. Oil from the seeds of this plant contained on average 11% EPA and 8% DHA in one development and 24% EPA in another.


title: Omega-3 fatty acid

text: Eggs produced by hens fed a diet of greens and insects contain higher levels of omega−3 fatty acids than those produced by chickens fed corn or soybeans. In addition to feeding chickens insects and greens, fish oils may be added to their diets to increase the omega−3 fatty acid concentrations in eggs.


title: Omega-3 fatty acid

text: The addition of flax and canola seeds, both good sources of alpha-linolenic acid, to the diets of laying chickens, increases the omega−3 content of the eggs, predominantly DHA. However, this enrichment could lead to an increment of lipid oxidation in the eggs if the seeds are used in higher doses, without using an appropriate antioxidant.


title: Omega-3 fatty acid

text: The addition of green algae or seaweed to the diets boosts the content of DHA and EPA, which are the forms of omega−3 approved by the FDA for medical claims. A common consumer complaint is "Omega−3 eggs can sometimes have a fishy taste if the hens are fed marine oils".


title: Omega-3 fatty acid

text: Omega−3 fatty acids are formed in the chloroplasts of green leaves and algae. While seaweeds and algae are the sources of omega−3 fatty acids present in fish, grass is the source of omega−3 fatty acids present in grass-fed animals. When cattle are taken off omega−3 fatty acid-rich grass and shipped to a feedlot to be fattened on omega−3 fatty acid deficient grain, they begin losing their store of this beneficial fat. Each day that an animal spends in the feedlot, the amount of omega−3 fatty acids in its meat is diminished.


title: Omega-3 fatty acid

text: The omega−6:omega−3 ratio of grass-fed beef is about 2:1, making it a more useful source of omega−3 than grain-fed beef, which usually has a ratio of 4:1.


title: Omega-3 fatty acid

text: In a 2009 joint study by the USDA and researchers at Clemson University in South Carolina, grass-fed beef was compared with grain-finished beef. The researchers found that grass-finished beef is higher in moisture content, 42.5% lower total lipid content, 54% lower in total fatty acids, 54% higher in beta-carotene, 288% higher in vitamin E (alpha-tocopherol), higher in the B-vitamins thiamin and riboflavin, higher in the minerals calcium, magnesium, and potassium, 193% higher in total omega−3s, 117% higher in CLA (cis-9, trans-11 octadecenoic acid, a conjugated linoleic acid, which is a potential cancer fighter), 90% higher in vaccenic acid (which can be transformed into CLA), lower in the saturated fats, and has a healthier ratio of omega−6 to omega−3 fatty acids (1.65 vs 4.84). Protein and cholesterol content were equal.


title: Omega-3 fatty acid

text: The omega−3 content of chicken meat may be enhanced by increasing the animals' dietary intake of grains high in omega−3, such as flax, chia, and canola.


title: Omega-3 fatty acid

text: Kangaroo meat is also a source of omega−3, with fillet and steak containing 74 mg per 100 g of raw meat.


title: Omega-3 fatty acid

text: Seal oil is a source of EPA, DPA, and DHA, and is commonly used in Arctic regions. According to Health Canada, it helps to support the development of the brain, eyes, and nerves in children up to 12 years of age. Like all seal products, it is not allowed to be imported into the European Union.


title: Omega-3 fatty acid

text: A trend in the early 21st century was to fortify food with omega−3 fatty acids. The microalgae "Crypthecodinium cohnii" and "Schizochytrium" are rich sources of DHA, but not EPA, and can be produced commercially in bioreactors for use as food additives. Oil from brown algae (kelp) is a source of EPA. The alga "Nannochloropsis" also has high levels of EPA.


title: Omega-3 fatty acid

text: There is insufficient evidence that supplementation with omega−3 fatty acids has an effect on different cancers. Omega-3 supplements do not improve body weight, muscle maintenance or quality of life in cancer patients.


title: Omega-3 fatty acid

text: Moderate and high quality evidence from a 2020 review showed that EPA and DHA, such as that found in omega−3 polyunsaturated fatty acid supplements, does not appear to improve mortality or cardiovascular health. There is weak evidence indicating that α-linolenic acid may be associated with a small reduction in the risk of a cardiovascular event or the risk of arrhythmia.


title: Omega-3 fatty acid

text: A 2018 meta-analysis found no support that daily intake of one gram of omega−3 fatty acid in individuals with a history of coronary heart disease prevents fatal coronary heart disease, nonfatal myocardial infarction or any other vascular event. However, omega−3 fatty acid supplementation greater than one gram daily for at least a year may be protective against cardiac death, sudden death, and myocardial infarction in people who have a history of cardiovascular disease. No protective effect against the development of stroke or all-cause mortality was seen in this population.


title: Omega-3 fatty acid

text: Fish oil supplementation has not been shown to benefit revascularization or abnormal heart rhythms and has no effect on heart failure hospital admission rates. Furthermore, fish oil supplement studies have failed to support claims of preventing heart attacks or strokes. In the EU, a review by the European Medicines Agency of omega−3 fatty acid medicines containing a combination of an ethyl ester of eicosapentaenoic acid and docosahexaenoic acid at a dose of 1 g per day concluded that these medicines are not effective in secondary prevention of heart problems in patients who have had a myocardial infarction.


title: Omega-3 fatty acid

text: Evidence suggests that omega−3 fatty acids modestly lower blood pressure (systolic and diastolic) in people with hypertension and in people with normal blood pressure. Omega−3 fatty acids can also reduce heart rate, an emerging risk factor. Some evidence suggests that people with certain circulatory problems, such as varicose veins, may benefit from the consumption of EPA and DHA, which may stimulate blood circulation and increase the breakdown of fibrin, a protein involved in blood clotting and scar formation.


title: Omega-3 fatty acid

text: Omega−3 fatty acids reduce blood triglyceride levels, but do not significantly change the level of LDL cholesterol or HDL cholesterol. The American Heart Association position (2011) is that borderline elevated triglycerides, defined as 150–199 mg/dL, can be lowered by 0.5–1.0 grams of EPA and DHA per day; high triglycerides 200–499 mg/dL benefit from 1–2 g/day; and >500 mg/dL be treated under a physician's supervision with 2–4 g/day using a prescription product. In this population omega−3 fatty acid supplementation decreases the risk of heart disease by about 25%.


title: Omega-3 fatty acid

text: A 2019 review found that omega-3 fatty acid supplements make little or no difference to cardiovascular mortality and that patients with myocardial infarction yield no benefit in taking the supplements. A 2021 review found that omega-3 supplementation did not affect cardiovascular disease outcomes. A 2021 meta-analysis showed that use of marine omega-3 supplementation was associated with an increased risk of atrial fibrillation, with the risk appearing to increase for doses greater than one gram per day.


title: Omega-3 fatty acid

text: A 2022 Cochrane review of controlled trials did not find clear evidence that marine-derived omega-3 supplementation improves cognitive and physical recovery or social, and emotional wellbeing following stroke diagnosis, nor prevents stroke recurrence and mortality. In this review, mood appeared to worsen slightly among those receiving 3g fish oil supplementation for 12 weeks; psychometric scores changed by 1.41 (0.07 to 2.75) points less than those receiving palm and soy oil. However this represented only a single small study and was not observed in a study lasting more than 3 months. Overall, the review was limited by the low number of high-quality evidence available.


title: Omega-3 fatty acid

text: A 2013 systematic review found tentative evidence of benefit for lowering inflammation levels in healthy adults and in people with one or more biomarkers of metabolic syndrome. Consumption of omega−3 fatty acids from marine sources lowers blood markers of inflammation such as C-reactive protein, interleukin 6, and TNF alpha.


title: Omega-3 fatty acid

text: For rheumatoid arthritis, one systematic review found consistent but modest, evidence for the effect of marine n−3 PUFAs on symptoms such as "joint swelling and pain, duration of morning stiffness, global assessments of pain and disease activity" as well as the use of non-steroidal anti-inflammatory drugs. The American College of Rheumatology has stated that there may be modest benefit from the use of fish oils, but that it may take months for effects to be seen, and cautions for possible gastrointestinal side effects and the possibility of the supplements containing mercury or vitamin A at toxic levels. The National Center for Complementary and Integrative Health has concluded that "supplements containing omega−3 fatty acids... may help relieve rheumatoid arthritis symptoms" but warns that such supplements "may interact with drugs that affect blood clotting".


title: Omega-3 fatty acid

text: One meta-analysis concluded that omega−3 fatty acid supplementation demonstrated a modest effect for improving ADHD symptoms. A Cochrane review of PUFA (not necessarily omega−3) supplementation found "there is little evidence that PUFA supplementation provides any benefit for the symptoms of ADHD in children and adolescents", while a different review found "insufficient evidence to draw any conclusion about the use of PUFAs for children with specific learning disorders". Another review concluded that the evidence is inconclusive for the use of omega−3 fatty acids in behavior and non-neurodegenerative neuropsychiatric disorders such as ADHD and depression.


title: Omega-3 fatty acid

text: A 2015 meta-analysis of the effect of omega−3 supplementation during pregnancy did not demonstrate a decrease in the rate of preterm birth or improve outcomes in women with singleton pregnancies with no prior preterm births. A 2018 Cochrane systematic review with moderate to high quality of evidence suggested that omega−3 fatty acids may reduce risk of perinatal death, risk of low body weight babies; and possibly mildly increased LGA babies.


title: Omega-3 fatty acid

text: A 2021 umbrella review with moderate to high quality of evidence suggested that "omega-3 supplementation during pregnancy can exert favorable effects against pre-eclampsia, low-birth weight, pre-term delivery, and post-partum depression, and can improve anthropometric measures, immune system, and visual activity in infants and cardiometabolic risk factors in pregnant mothers."


title: Omega-3 fatty acid

text: Omega-3 supplementation has not been shown to significantly affect symptoms of anxiety, major depressive disorder or schizophrenia. A 2021 Cochrane review concluded that there is not "sufficient high‐certainty evidence to determine the effects of n‐3PUFAs as a treatment for MDD". Omega−3 fatty acids have also been investigated as an add-on for the treatment of depression associated with bipolar disorder although there is limited data available. Two reviews have suggested that omega-3 fatty acid supplementation significantly improves depressive symptoms in perinatal women.


title: Omega-3 fatty acid

text: In contrast to dietary supplementation studies, there is significant difficulty in interpreting the literature regarding dietary intake of omega−3 fatty acids (e.g. from fish) due to participant recall and systematic differences in diets. There is also controversy as to the efficacy of omega−3, with many meta-analysis papers finding heterogeneity among results which can be explained mostly by publication bias. A significant correlation between shorter treatment trials was associated with increased omega−3 efficacy for treating depressed symptoms further implicating bias in publication.


title: Omega-3 fatty acid

text: A 2016 Cochrane review found no convincing evidence for the use of omega‐3 PUFA supplements in treatment of Alzheimer's disease or dementia. There is preliminary evidence of effect on mild cognitive problems, but none supporting an effect in healthy people or those with dementia. A 2020 review suggested that omega 3 supplementation has no effect on global cognitive function but has a mild benefit in improving memory in non-demented adults.


title: Omega-3 fatty acid

text: A 2022 review found promising evidence for prevention of cognitive decline in people who regularly eat long-chain omega 3 rich foods. Conversely, clinical trials with participants already diagnosed with Alzheimer's show no effect.


title: Omega-3 fatty acid

text: Brain function and vision rely on dietary intake of DHA to support a broad range of cell membrane properties, particularly in grey matter, which is rich in membranes. A major structural component of the mammalian brain, DHA is the most abundant omega−3 fatty acid in the brain. Omega 3 PUFA supplementation has no effect on macular degeneration or development of visual loss.


title: Omega-3 fatty acid

text: Results of studies investigating the role of LCPUFA supplementation and LCPUFA status in the prevention and therapy of atopic diseases (allergic rhinoconjunctivitis, atopic dermatitis, and allergic asthma) are controversial; therefore, it could not be stated either that the nutritional intake of n−3 fatty acids has a clear preventive or therapeutic role, or that the intake of n-6 fatty acids has a promoting role in the context of atopic diseases.


title: Omega-3 fatty acid

text: People with PKU often have low intake of omega−3 fatty acids, because nutrients rich in omega−3 fatty acids are excluded from their diet due to high protein content.


title: Omega-3 fatty acid

text: As of 2015, there was no evidence that taking omega−3 supplements can prevent asthma attacks in children.


title: Omega-3 fatty acid

text: A 2019 review found that omega-3 supplements have no effect on prevention and treatment of type 2 diabetes.


title: HMS Hood

text: HMS "Hood" (pennant number 51) was a battlecruiser of the Royal Navy (RN). "Hood" was the first of the planned four s to be built during the First World War. Already under construction when the Battle of Jutland occurred in mid-1916, that battle revealed serious flaws in her design despite drastic revisions before she was completed four years later. For this reason, she was the only ship of her class to be completed, as the Admiralty decided it would be better to start with a clean design on succeeding battlecruisers, leading to the never-built G-3 class. Despite the appearance of newer and more modern ships, "Hood" remained the largest warship in the world for 20 years after her commissioning, and her prestige was reflected in her nickname, "The Mighty Hood".


title: HMS Hood

text: "Hood" was involved in many showing-the-flag exercises between her commissioning in 1920 and the outbreak of war in 1939, including training exercises in the Mediterranean Sea and a circumnavigation of the globe with the Special Service Squadron in 1923 and 1924. She was attached to the Mediterranean Fleet following the outbreak of the Second Italo-Ethiopian War in 1935. When the Spanish Civil War broke out the following year, "Hood" was officially assigned to the Mediterranean Fleet until she had to return to Britain in 1939 for an overhaul. By this time, advances in naval gunnery had reduced "Hood"s usefulness. She was scheduled to undergo a major rebuild in 1941 to correct these issues, but the outbreak of the Second World War in September 1939 kept the ship in service without the upgrades.


title: HMS Hood

text: When war with Germany was declared, "Hood" was operating in the area around Iceland, and she spent the next several months hunting for German commerce raiders and blockade runners between Iceland and the Norwegian Sea. After a brief overhaul of her propulsion system, she sailed as the flagship of Force H, and participated in the destruction of the French fleet at Mers-el-Kebir. Transferred to the Home Fleet shortly afterwards, "Hood" was dispatched to Scapa Flow, and operated in the area as a convoy escort and later as a defence against a potential German invasion fleet.


title: HMS Hood

text: In May 1941, "Hood" and the battleship were ordered to intercept the and the heavy cruiser , which were en route to the Atlantic, where they were to attack convoys. On 24 May 1941, early in the Battle of the Denmark Strait, "Hood" was struck by several German shells, exploded, and sank with the loss of all but 3 of her crew of 1,418. Due to her publicly perceived invincibility, the loss affected British morale.


title: HMS Hood

text: The RN conducted two inquiries into the reasons for the ship's quick demise. The first, held soon after the ship's loss, concluded that "Hood"s aft magazine had exploded after one of "Bismarck"s shells penetrated the ship's armour. A second inquiry was held after complaints that the first board had failed to consider alternative explanations, such as an explosion of the ship's torpedoes. It was more thorough than the first board but concurred with the first board's conclusion. Despite the official explanation, some historians continued to believe that the torpedoes caused the ship's loss, while others proposed an accidental explosion inside one of the ship's gun turrets that reached down into the magazine. Other historians have concentrated on the cause of the magazine explosion. The discovery of the ship's wreck in 2001 confirmed the conclusion of both boards, although the exact reason the magazines detonated is likely to remain unknown since that portion of the ship was obliterated in the explosion.


title: HMS Hood

text: The Admiral-class battlecruisers were designed in response to the German s, which were reported to be more heavily armed and armoured than the latest British battlecruisers of the and the es. The design was revised after the Battle of Jutland to incorporate heavier armour and all four ships were laid down. Only "Hood" was completed, because the ships were very expensive and required labour and material that could be put to better use building merchant ships needed to replace those lost to the German U-boat campaign.


title: HMS Hood

text: The Admirals were significantly larger than their predecessors of the "Renown" class. As completed, "Hood" had an overall length of , a maximum beam of , and a draught of at deep load. This was longer and wider than the older ships. She displaced at load and at deep load, over more than the older ships. The ship had a metacentric height of at deep load, which minimised her roll and made her a steady gun platform.


title: HMS Hood

text: The additional armour added during construction increased her draught by about at deep load, which reduced her freeboard and made her very wet. At full speed, or in heavy seas, water would flow over the ship's quarterdeck and often entered the messdecks and living quarters through ventilation shafts. This characteristic earned her the nickname of "the largest submarine in the Navy". The persistent dampness, coupled with the ship's poor ventilation, was blamed for the high incidence of tuberculosis aboard. The ship's complement varied widely over her career; in 1919, she was authorised 1,433 men as a squadron flagship; in 1934, she had 81 officers and 1,244 ratings aboard.


title: HMS Hood

text: The Admirals were powered by four Brown-Curtis geared steam turbines, each driving one propeller shaft using steam provided by 24 Yarrow boilers. The battlecruiser's turbines were designed to produce , which would propel the ship at , but during sea trials in 1920, "Hood"s turbines provided , which allowed her to reach . She carried enough fuel oil to give her an estimated range of at .


title: HMS Hood

text: The main battery of the Admiral-class ships consisted of eight BL Mk I guns in hydraulically powered twin gun turrets. The turrets were designated 'A', 'B', 'X', and 'Y' from bow to stern, and 120 shells were carried for each gun. The ship's secondary armament consisted of twelve BL Mk I guns, each with 200 rounds. They were shipped on shielded single-pivot mounts fitted along the upper deck and the forward shelter deck. This high position allowed them to be worked during heavy weather, as they were less affected by waves and spray compared with the casemate mounts of earlier British capital ships. Two of these guns on the shelter deck were temporarily replaced by QF Mk V anti-aircraft (AA) guns between 1938 and 1939. All the 5.5-inch guns were removed during another refit in 1940.


title: HMS Hood

text: The ship's original anti-aircraft armament consisted of four QF 4-inch Mk V guns on single mounts. These were joined in early 1939 by four twin mounts for the QF 4-inch Mark XVI dual-purpose gun. The single guns were removed in mid-1939 and a further three twin Mark XIX mounts were added in early 1940. In 1931, a pair of octuple mountings for the QF 2-pounder Mk VIII gun "pom-pom" were added on the shelter deck, abreast of the funnels, and a third mount was added in 1937. Two quadruple mountings for the Vickers Mk III machine gun were added in 1933 with two more mountings added in 1937. To these were added five unrotated projectile (UP) launchers in 1940, each launcher carrying 20 rockets. When they detonated, the rockets shot out lengths of cable that were kept aloft by parachutes; the cable was intended to snag aircraft and draw up the small aerial mine that would destroy the aircraft.


title: HMS Hood

text: The Admirals were fitted with six fixed torpedo tubes, three on each broadside. Two of these were submerged forward of 'A' turret's magazine and the other four were above water, abaft the rear funnel. About 28 torpedoes were carried.


title: HMS Hood

text: The ship's main battery was controlled by two fire-control directors. One was mounted above the conning tower, protected by an armoured hood, and was fitted with a rangefinder. The other was fitted in the spotting top above the tripod foremast and equipped with a rangefinder. Each turret was also fitted with a rangefinder. The secondary armament was primarily controlled by directors mounted on each side of the bridge. They were supplemented by two additional control positions in the fore-top, which were provided with rangefinders, fitted in 1924–1925. The antiaircraft guns were controlled by a simple high-angle rangefinder mounted on the aft control position, fitted in 1926–1927. Three torpedo-control towers were fitted, each with a rangefinder. One was on each side of the amidships control tower and the third was on the centreline abaft the aft control position.


title: HMS Hood

text: During the 1929–1931 refit, a high-angle control system (HACS) Mark I director was added on the rear searchlight platform and two positions for 2-pounder "pom-pom" antiaircraft directors were added at the rear of the spotting top, although only one director was initially fitted. The 5.5-inch control positions and their rangefinders on the spotting top were removed during the 1932 refit. In 1934, the "pom-pom" directors were moved to the former locations of the 5.5-inch control positions on the spotting top and the rangefinders for the 5.5-inch control positions were reinstalled on the signal platform. Two years later, the "pom-pom" directors were moved to the rear corners of the bridge to get them out of the funnel gases. Another "pom-pom" director was added on the rear superstructure, abaft the HACS director in 1938. Two HACS Mark III directors were added to the aft end of the signal platform the following year, and the Mark I director aft was replaced by a Mark III.


title: HMS Hood

text: During "Hood"s last refit in 1941, a Type 279 early-warning radar for aircraft and surface vessels and a Type 284 gunnery radar were installed, although the Type 279 radar lacked its receiving aerial and was inoperable according to Roberts. An Admiralty document indicates however that, following the 1941 refit at Rosyth, "Hood"s Type 279 radar was indeed functional. The early-warning radar was of a modified type, known as Type 279M, the difference between this and Type 279 being the number of aerials. While Type 279 used two aerials, a transmitter and a receiver, the Type 279M used only a single transceiver aerial. "Hood" reported an accuracy of 3 degrees with her 279M set.


title: HMS Hood

text: The armour scheme of the Admirals was originally based on that of the battlecruiser with an waterline belt. Unlike "Tiger", the armour was angled outwards 12° from the waterline to increase its relative thickness in relation to flat-trajectory shells. This change increased the ship's vulnerability to plunging (high-trajectory) shells, as it exposed more of the vulnerable deck armour. Some of armour were added to the design in late 1916, based on British experiences at the Battle of Jutland, at the cost of deeper draught and slightly decreased speed. To save construction time, this was accomplished by thickening the existing armour, rather than redesigning the entire ship. "Hood"s protection accounted for 33% of her displacement, a high proportion by British standards, but less than was usual in contemporary German designs (for example, 36% for the battlecruiser ).


title: HMS Hood

text: The armoured belt consisted of face-hardened Krupp cemented armour (KC), arranged in three strakes. The main waterline belt was 12 inches (305 mm) thick between 'A' and 'Y' barbettes and thinned to 5 to 6 inches (127 to 152 mm) towards the ship's ends, but did not reach either the bow or the stern. The middle armour belt had a maximum thickness of 7 inches over the same length as the thickest part of the waterline armour and thinned to five inches abreast 'A' barbette. The upper belt was 5 inches thick amidships and extended forward to 'A' barbette, with a short 4-inch extension aft.


title: HMS Hood

text: The gun turrets and barbettes were protected by of KC armour, except for the turret roofs, which were 5 inches thick. The decks were made of high-tensile steel. The forecastle deck ranged from 1.75 to 2 inches (44 to 51 mm) in thickness, while the upper deck was 2 inches (51 mm) thick over the magazines and 0.75 inches (19 mm) elsewhere. The main deck was 3 inches (76 mm) thick over the magazines and 1 inch (25 mm) elsewhere, except for the 2-inch-thick slope that met the bottom of the main belt. The lower deck was 3 inches thick over the propeller shafts, 2 inches thick over the magazines and 1 inch elsewhere.


title: HMS Hood

text: Live-firing trials with the new 15-inch APC (armour-piercing, capped) shell against a mock-up of "Hood" showed that this shell could penetrate the ship's vitals via the 7-inch middle belt and the 2-inch slope of the main deck as a result 3-inch plating on the main deck over the slopes was added alongside the magazine spaces at a very late stage of construction and the four aftermost 5.5-inch guns and their ammunition hoists were removed in partial compensation.. A proposal was made to increase the armour over the forward magazines to 5 inches and 6 inches over the rear magazines in July 1919 in response to these trials. To compensate for the additional weight, the 4 midships above water torpedo tubes and the armour for the rear torpedo warheads were removed, and the armour for the aft torpedo-control tower was reduced in thickness from 6 to . However, the additional armour was never fitted pending further trials. As completed, "Hood" remained susceptible to plunging shells and bombs. The torpedo-warhead armour was reinstated during the ship's 1929–1931 refit.


title: HMS Hood

text: For protection against torpedoes, she was given a deep torpedo bulge that ran the length of the ship between the fore and aft barbettes. It was divided into an empty outer compartment and an inner compartment filled with five rows of water-tight "crushing tubes" intended to absorb and distribute the force of an explosion. The bulge was backed by a 1.5-inch-thick torpedo bulkhead.


title: HMS Hood

text: "Hood" was initially fitted with flying-off platforms mounted on top of 'B' and 'X' turrets, from which Fairey Flycatchers could launch. During her 1929–1931 refit, the platform was removed from 'X' turret and a rotating, folding catapult was installed on her quarterdeck, along with a crane to recover a seaplane. She embarked a Fairey IIIF from No. 444 Flight of the Royal Air Force (RAF). During the 1932 West Indies cruise, the catapult proved to be difficult to operate in anything but a calm sea, as it was frequently awash in bad weather. The catapult and crane were removed in 1932, along with the flying-off platform on 'B' turret.


title: HMS Hood

text: Although the Royal Navy always designated "Hood" as a battlecruiser, some modern writers such as Anthony Preston have classified her as a fast battleship, since "Hood" appeared to have improvements over the fast s. On paper, "Hood" retained the same armament and level of protection, while being significantly faster.


title: HMS Hood

text: Around 1918, American commanders, including Vice Admiral William Sims, commander of US naval forces in Europe, and Admiral Henry T. Mayo, commander of the Atlantic Fleet, became extremely impressed by "Hood", which they described as a "fast battleship", and they advocated that the US Navy develop a fast battleship of its own. However, the US continued with their established design direction, the slower, but well-protected, battleship and the fast and lightly armoured , both of which were later cancelled in accordance with the terms of the Washington Naval Treaty of 1922.


title: HMS Hood

text: Influences from "Hood" showed on subsequent "Lexington" designs, with the reduction of the main armour belt, the change to "sloped armour", and the addition of four above-water torpedo tubes to the four underwater tubes of the original design. To add to the confusion, Royal Navy documents of the period often describe any battleship with a maximum speed over as a battlecruiser, regardless of the amount of protective armour. For instance, the never-built G3 battlecruiser was classified as such, although it would have been more of a fast battleship than "Hood".


title: HMS Hood

text: The scale of "Hood"s protection, though adequate for the Jutland era, was at best marginal against the new generation of gunned capital ships that emerged soon after her completion in 1920, typified by the American and the Japanese s. The Royal Navy were fully aware that the ship's protection flaws still remained, even in her revised design, so "Hood" was intended for the duties of a battlecruiser and she served in the battlecruiser squadrons through most of her career. Late in her career, "Hood" was outclassed by the armour and protective arrangement of Second World War-era fast battleships, but few of the RN's available "big gun" vessels could match "Bismarck"s speed.


title: HMS Hood

text: Construction of "Hood" began at the John Brown & Company shipyard in Clydebank, Scotland, as yard number 460 on 1 September 1916. Following the loss of three British battlecruisers at the Battle of Jutland, 5,000 tons of extra armour and bracing were added to "Hood"s design. Most seriously, the deck protection was flawed—spread over three decks, it was designed to detonate an incoming shell on impact with the top deck, with much of the energy being absorbed as the exploding shell had to penetrate the armour of the next two decks. The development of effective time-delay shells at the end of the First World War made this scheme much less effective, as the intact shell would penetrate layers of weak armour and explode deep inside the ship. In addition, she was grossly overweight compared to her original design, making her a wet ship with a highly stressed structure.


title: HMS Hood

text: She was launched on 22 August 1918 by the widow of Rear Admiral Sir Horace Hood, a great-great-grandson of Admiral Samuel Hood, after whom the ship was named. Sir Horace Hood had been killed while commanding the 3rd Battlecruiser Squadron and flying his flag on —one of the three battlecruisers which blew up at the Battle of Jutland. To make room in the shipyard for merchant construction, "Hood" sailed for Rosyth to complete her fitting-out on 9 January 1920. After her sea trials, she was commissioned on 15 May 1920, under Captain Wilfred Tompkinson. She had cost £6,025,000 to build.


title: HMS Hood

text: With her conspicuous twin funnels and lean profile, "Hood" was widely regarded as one of the finest-looking warships ever built. She was also the largest warship afloat when she was commissioned, and retained that distinction for the next 20 years. Her size and powerful armament earned her the nickname of "Mighty Hood" and she came to symbolise the might of the British Empire itself.


title: HMS Hood

text: Shortly after commissioning on 15 May 1920, "Hood" became the flagship of the Battlecruiser Squadron of the Atlantic Fleet, under the command of Rear Admiral Sir Roger Keyes. After a cruise to Scandinavian waters that year, Captain Geoffrey Mackworth assumed command. "Hood" visited the Mediterranean in 1921 and 1922 to show the flag and to train with the Mediterranean fleet, before sailing on a cruise to Brazil and the West Indies in company with the battlecruiser squadron.


title: HMS Hood

text: Captain John Im Thurn was in command when "Hood", accompanied by the battlecruiser and s of the 1st Light Cruiser Squadron, set out on a world cruise from west to east via the Panama Canal in November 1923. The objective of the cruise was to remind the dominions of their dependence on British sea power and encourage them to support it with money, ships, and facilities. They returned home 10 months later in September 1924, having visited South Africa, India, Australia, New Zealand, Canada, and some smaller colonies and dependencies, and the United States.


title: HMS Hood

text: While in Australia in April 1924, the squadron escorted the battlecruiser out to sea, where she was scuttled in compliance with the Washington Naval Treaty. The battlecruiser squadron visited Lisbon in January 1925 to participate in the Vasco da Gama celebrations before continuing on to the Mediterranean for exercises. "Hood" continued this pattern of a winter training visit to the Mediterranean for the rest of the decade. Captain Harold Reinold relieved Captain im Thurn on 30 April 1925 and was relieved in turn by Captain Wilfred French on 21 May 1927.


title: HMS Hood

text: "Hood" was given a major refit from 1 May 1929 to 10 March 1931, and afterwards resumed her role as flagship of the battlecruiser squadron under the command of Captain Julian Patterson. Later that year, her crew participated in the Invergordon Mutiny over pay cuts for the sailors. It ended peacefully and "Hood" returned to her home port afterwards. The battlecruiser squadron made a Caribbean cruise in early 1932, and "Hood" was given another brief refit between 31 March and 10 May at Portsmouth. Captain Thomas Binney assumed command on 15 August 1932 and the ship resumed her previous practice of a winter cruise in the Mediterranean the next year. Captain Thomas Tower replaced Captain Binney on 30 August 1933. Her secondary and antiaircraft fire-control directors were rearranged during another quick refit between 1 August and 5 September 1934.


title: HMS Hood

text: While en route to Gibraltar for a Mediterranean cruise, "Hood" was rammed in the port side quarterdeck by the battlecruiser on 23 January 1935. The damage to "Hood" was limited to her left outer propeller and an 18-inch (460 mm) dent, although some hull plates were knocked loose from the impact. Temporary repairs were made at Gibraltar before the ship sailed to Portsmouth for permanent repairs between February and May 1935. The captains of both ships were court-martialled, as was the squadron commander, Rear Admiral Sidney Bailey. Tower and Bailey were acquitted, but "Renown"s Captain Sawbridge was relieved of command. The Admiralty dissented from the verdict, reinstated Sawbridge, and criticised Bailey for ambiguous signals during the manoeuvre.


title: HMS Hood

text: The ship participated in King George V's Silver Jubilee Fleet Review at Spithead the following August. She was attached to the Mediterranean fleet shortly afterwards and stationed at Gibraltar at the outbreak of the Second Italo-Abyssinian War in October. Captain Arthur Pridham assumed command on 1 February 1936 and "Hood" returned to Portsmouth for a brief refit between 26 June and 10 October 1936. She formally transferred to the Mediterranean fleet on 20 October, shortly after the beginning of the Spanish Civil War. On 23 April 1937, the ship escorted three British merchantmen into Bilbao harbour despite the presence of the Nationalist cruiser that attempted to blockade the port. "Hood" was refitted at Malta in November and December 1937, and had her submerged torpedo tubes removed. Captain Pridham was relieved by Captain Harold Walker on 20 May 1938 and he, in turn, was relieved when the ship returned to Portsmouth in January 1939 for an overhaul that lasted until 12 August.


title: HMS Hood

text: "Hood" was due to be modernised in 1941 to bring her up to a standard similar to that of other modernised First World War-era capital ships. She would have received new, lighter turbines and boilers, a secondary armament of eight twin gun turrets, and six octuple 2-pounder "pom-poms". Her 5-inch upper-armour strake would have been removed and her deck armour reinforced. A catapult would have been fitted across the deck and the remaining torpedo tubes removed. In addition, the conning tower would have been removed and her bridge rebuilt. The ship's near-constant active service, resulting from her status as the Royal Navy's most battle-worthy fast capital ship, meant that her material condition gradually deteriorated, and by the mid-1930s, she was in need of a lengthy overhaul. The outbreak of the Second World War made removing her from service near impossible, and as a consequence, she never received the scheduled modernisation afforded to other capital ships such as "Renown" and several of the "Queen Elizabeth"-class battleships. The ship's condensers were in such bad condition by this time that much of the output from the fresh-water evaporators was required to replenish the boiler feedwater and could not be used by the crew to wash and bathe or even to heat the mess decks during cold weather, as the steam pipes were too leaky. These problems also reduced her steam output so that she was unable to attain her designed speed.


title: HMS Hood

text: Captain Irvine Glennie assumed command in May 1939 and "Hood" was assigned to the Home Fleet's Battlecruiser Squadron while still refitting. When war broke out later that year, she was employed principally to patrol in the vicinity of Iceland and the Faroe Islands to protect convoys and intercept German merchant raiders and blockade runners attempting to break out into the Atlantic. On 25 September 1939, the Home Fleet sortied into the central North Sea to cover the return of the damaged submarine . The fleet was spotted by the Germans and attacked by aircraft from the KG 26 and KG 30 bomber wings. "Hood" was hit by a 250 kg (550 lb) bomb from a Junkers Ju 88 bomber that damaged her port torpedo bulge and her condensers. By early 1940, "Hood"s machinery was in dire shape and limited her best speed to ; she was refitted between 4 April and 12 June.


title: HMS Hood

text: "Hood" and the aircraft carrier were ordered to Gibraltar to join Force H on 18 June where "Hood" became the flagship. Force H took part in the destruction of the French fleet at Mers-el-Kébir in July 1940. Just eight days after the French surrender, the British Admiralty issued an ultimatum that the French fleet at Oran intern its ships in a British or neutral port to ensure they would not fall into Axis hands. The terms were rejected and the Royal Navy opened fire on the French ships berthed there. The results of "Hood"s fire are not known exactly, but she damaged the , which was hit by four fifteen-inch shells and was forced to beach herself. "Hood" was straddled during the engagement by "Dunkerque"; shell splinters wounded two men. "Dunkerque"s sister ship, , managed to escape from the harbour. "Hood" and several light cruisers gave chase, but gave up after two hours; "Hood" had dodged a salvo of torpedoes from a French sloop and had damaged a turbine reaching .


title: HMS Hood

text: "Hood" was relieved as flagship of Force H by "Renown" on 10 August, after returning to Scapa Flow. On 13 September she was sent to Rosyth along with the battleships and and other ships, to be in a better position to intercept a German invasion fleet. When the threat of an invasion diminished, the ship resumed her previous roles in convoy escort and patrolling against German commerce raiders. "Hood", "Renown" and "Repulse" were deployed to the Bay of Biscay on 5 November to prevent the "pocket battleship" from using French ports after she had attacked Convoy HX 84, but the German ship continued into the South Atlantic.


title: HMS Hood

text: In January 1941, the ship began a refit that lasted until March; even after the refit she was still in poor condition, but the threat from the German capital ships was such that she could not be taken into dock for a major overhaul until more of the battleships came into service. Captain Ralph Kerr assumed command during the refit, and "Hood" was ordered to sea in an attempt to intercept the German battleships and upon the refit's completion in mid-March. Unsuccessful, she was ordered to patrol the Bay of Biscay against any breakout attempt by the German ships from Brest, France. "Hood" was ordered to the Norwegian Sea on 19 April when the Admiralty received a false report that the had sailed from Germany. Afterwards, she patrolled the North Atlantic before putting into Scapa Flow on 6 May.


title: HMS Hood

text: When "Bismarck" sailed for the Atlantic in May 1941, "Hood", flying the flag of Vice-Admiral Lancelot Holland, together with the newly commissioned battleship , was sent out in pursuit along with several other groups of British capital ships to intercept the German ships before they could break into the Atlantic and attack Allied convoys. The German ships were spotted by two British heavy cruisers ( and ) on 23 May, and Holland's ships intercepted "Bismarck" and her consort, the heavy cruiser , in the Denmark Strait between Greenland and Iceland on 24 May.


title: HMS Hood

text: The British squadron spotted the Germans at 05:37 (ship's clocks were set four hours ahead of local time—the engagement commenced shortly after dawn), but the Germans were already aware of their presence, "Prinz Eugen"s hydrophones having previously detected the sounds of high-speed propellers to their southeast. The British opened fire at 05:52 with "Hood" engaging "Prinz Eugen", the lead ship in the German formation, and the Germans returned fire at 05:55, both ships concentrating on "Hood". "Prinz Eugen" was probably the first ship to score when a shell hit "Hood"s boat deck, between her funnels, and started a large fire among the ready-use ammunition for the anti-aircraft guns and rockets of the UP mounts.


title: HMS Hood

text: Just before 06:00, while "Hood" was turning 20° to port to unmask her rear turrets, she was hit again on the boat deck by one or more shells from "Bismarck"s fifth salvo, fired from a range of approximately . A shell from this salvo appears to have hit the spotting top, as the boat deck was showered with body parts and debris. A huge jet of flame burst out of "Hood" from the vicinity of the mainmast, followed by a devastating magazine explosion that destroyed the aft part of the ship. This explosion broke the back of "Hood", and the last sight of the ship, which sank in only three minutes, was her bow, nearly vertical in the water. A note on a survivor's sketch in the RN Historical Branch Archives gives as the position of the sinking. "Hood" sank stern first with 1418 men aboard. Only three survived: Ordinary Signalman Ted Briggs (1923–2008), Able Seaman Robert Tilburn (1921–1995), and Midshipman William John Dundas (1923–1965). The three were rescued about two hours after the sinking by the destroyer , which spotted substantial debris but no bodies.


title: HMS Hood

text: "Prince of Wales" was forced to disengage by a combination of damage from German hits and mechanical failures in her guns and turrets after "Hood" was sunk. Despite these problems, she had hit "Bismarck" three times. One of these hits contaminated a good portion of the ship's fuel supply and subsequently caused her to steer for safety in occupied France where she could be repaired. "Bismarck" was temporarily able to evade detection, but was later spotted and sunk on 27 May.


title: HMS Hood

text: The official Admiralty communiqué on the loss, broadcast on the day of the sinking, reported that: "during the ... action, HMS "Hood" ... received an unlucky hit in a magazine and blew up." The first formal board of enquiry into the loss, presided over by Vice-Admiral Sir Geoffrey Blake, reported on 2 June, less than a fortnight after the loss. It endorsed this opinion, stating that:


title: HMS Hood

text: Admiral Tom Phillips and others criticised the conduct of the inquiry, largely because no verbatim record of witnesses' testimony had been kept. Moreover, Sir Stanley V. Goodall, Director of Naval Construction came forward with an alternative theory, that the "Hood" had been destroyed by the explosion of her own torpedoes. As a result, a second Board was convened under Rear Admiral Sir Harold Walker and reported in September 1941. This investigation was "much more thorough than was the first, taking evidence from a total of 176 eyewitnesses to the disaster", and examined both Goodall's theory and others (see below). The Board came to a conclusion almost identical to that of the first board, expressed as follows:


title: HMS Hood

text: Memorials to those who died are spread widely around the UK, and some of the crew are commemorated in different locations. One casualty, George David Spinner, is remembered on the Portsmouth Naval memorial, the "Hood" Chapel at the Church of St John the Baptist, in Boldre, Hampshire, and also on the gravestone of his brother, who died while serving in the Royal Air Force in 1942, in the Hamilton Road Cemetery, Deal, Kent.


title: HMS Hood

text: The exact cause of the loss of "Hood" remains a subject of debate. The principal theories include the following causes:


title: HMS Hood

text: At the second board, expert witnesses suggested that what was observed was the venting, through the engine-room ventilators, of a violent—but not instantaneous—explosion or deflagration in the 4-inch shell magazines. The same deflagration would have collapsed the bulkhead separating the 4-inch and 15-inch magazines, resulting very quickly in a catastrophic explosion similar to those previously witnessed at Jutland. This theory was ultimately adopted by the board.


title: HMS Hood

text: An extensive review of these theories (excepting that of Preston) is given in Jurens's 1987 article. Its main conclusion is that the loss was almost certainly precipitated by the explosion of a 4-inch magazine, but that there are several ways this could have been initiated, although he rules out the boat deck fire or the detonation of her torpedoes as probable causes. In Jurens's opinion, the popular image of plunging shells penetrating "Hood"s deck armour is inaccurate, as by his estimation the angle of fall of "Bismarck"s 15-inch shells at the moment of the loss would not have exceeded about 14°, an angle so unfavourable to penetration of horizontal armour that it is actually off the scale of contemporaneous German penetration charts. Moreover, computer-generated profiles of "Hood" show that a shell falling at this angle could not have reached an aft magazine without first passing through some part of the belt armour. On the other hand, the 12-inch belt could have been penetrated if "Hood" had progressed sufficiently far into her final turn.


title: HMS Hood

text: A more recent development is the discovery of "Hood"s wreck. Inspection of the wreck has confirmed that the aft magazines did indeed explode. The stern of the "Hood" was located, with the rudder still in place, and it was found that this was set to port at the time of the explosion. Furthermore, a section of the bow immediately forward of 'A' turret is missing, which has led historian and former Dartmouth lecturer Eric J. Grove and expedition leader David Mearns to believe that "either just before or just after leaving the surface, the bow suffered massive internal damage from an internal explosion", possibly a partial detonation of the forward 15-inch magazines.


title: HMS Hood

text: It has been suggested that the fatal fire spread from the aft end of the ship through the starboard fuel tanks, since the starboard side of "Hood" "appears to be missing most, if not all of its torpedo bulge plating".


title: HMS Hood

text: The evidence of the wreck refutes Goodall's theory of a torpedo explosion, while the eyewitness evidence of venting from the 4-inch magazine prior to the main explosion conflicts with the theory that the "Hood" was blown up by her own guns. The other theories listed above remain valid possibilities.


title: HMS Hood

text: In their study of the battleship "Bismarck"s operational history released in 2019, including its engagement with "Hood", Jurens, William Garzke, and Robert O. Dulin Jr. concluded that "Hood"'s destruction was most likely caused by a 380-mm shell from "Bismarck" that penetrated the deck armour and exploded in the aft 4-inch magazine, igniting its cordite propellant, which in turn ignited the cordite in the adjacent aft 15-inch magazine. Rapid expansion of the resulting combustion gases from the conflagration then caused structural failure, passing out through the sides of the ship as well as forward and upwards via the engine room vents, expelling the aft main battery turrets and causing the stern to be detached from the rest of the hull at the aft armoured bulkhead.


title: HMS Hood

text: In 2001, British broadcaster Channel 4 commissioned shipwreck hunter David Mearns and his company, Blue Water Recoveries, to locate the wreck of "Hood", and if possible, produce underwater footage of both the battlecruiser and her attacker, "Bismarck". This was to be used for a major event documentary to be aired on the 60th anniversary of the ships' battle. This was the first time anyone had attempted to locate "Hood"s resting place. Mearns had spent the previous six years privately researching the fate of "Hood" with the goal of finding the battlecruiser, and had acquired the support of the Royal Navy, the HMS "Hood" Association and other veterans groups, and the last living survivor, Ted Briggs.


title: HMS Hood

text: The search team and equipment had to be organised within four months, to take advantage of a narrow window of calm conditions in the North Atlantic. Organisation of the search was complicated by the presence on board of a documentary team and their film equipment, along with a television journalist who made live news reports via satellite during the search. The search team also planned to stream video from the remotely operated underwater vehicle (ROV) directly to Channel 4's website.


title: HMS Hood

text: After footage of "Bismarck" was collected, Mearns and the search team began scanning a search box for "Hood"; completely covering the area was estimated to take six days. Areas that Mearns felt were more likely to hold the wreck were prioritised, and the side-scan sonar located the battlecruiser in the 39th hour of the search.


title: HMS Hood

text: "Hood"s wreck lies on the seabed in pieces among two debris fields at a depth of about . The eastern field includes the small piece of the stern that survived the magazine explosion, as well as the surviving section of the bow and some smaller remains such as the propellers. The 4-inch fire-control director lies in the western debris field. The heavily armoured conning tower is located by itself a distance from the main wreck. The amidships section, the biggest part of the wreck to survive the explosions, lies inverted south of the eastern debris field in a large impact crater. The starboard side of the amidships section is missing down to the inner wall of the fuel tanks and the plates of the hull are curling outward; this has been interpreted as indicating the path of the explosion through the starboard fuel tanks.


title: HMS Hood

text: It is further supposed that the small debris fields are the fragments from the aft hull where the magazines and turrets were located, since that section of the hull was totally destroyed in the explosion. The fact that the bow section separated just forward of 'A' turret is suggestive that a secondary explosion might have occurred in this area. Other researchers have claimed that the final salvo fired by "Hood" was not a salvo at all, but flame from the forward magazine explosion, which gave the illusion of "Hood" firing for the last time. This damage, ahead of the armoured bulkhead, could have been implosion damage suffered while "Hood" sank, as a torpedo room that had been removed during one of her last refits approximates the site of the break.


title: HMS Hood

text: It was the opinion of Mearns and White who investigated the wreck that this was unlikely as the damage was far too limited in scale, nor could it account for the outwardly splayed plates also observed in that area. Bill Jurens points out that there was no magazine of any kind at the location of the break and that the location of the break just forward of the forward transverse armoured bulkhead suggests that the ship's structure failed there as a result of stresses inflicted when the bow was lifted into the vertical position by the sinking stern section. Furthermore, the current position of the plates at the edge of the break reflects only their last position, not the direction they had first moved.


title: HMS Hood

text: The forward section lies on its port side, with the amidships section keel up. The stern section rises from the seabed at an angle. This position shows the rudder locked into a 20° port turn, confirming that orders had been given (just prior to the aft magazines detonating) to change the ship's heading and bring the aft turrets 'X' and 'Y' to bear on the German ships.


title: HMS Hood

text: In 2002, the site was officially designated a war grave by the British government. As such, it remains a protected place under the Protection of Military Remains Act of 1986.


title: HMS Hood

text: In 2012, the British government gave permission for Mearns to return to the site of "Hood"s final resting place to retrieve one of her two ship's bells which were lying in a small open debris field some way from the wreck herself. With the backing of the HMS "Hood" Association, Mearns planned to return the bell to Portsmouth where it would form part of the first official and permanent memorial to the sacrifice of her last crew at the newly refitted National Museum of the Royal Navy.


title: HMS Hood

text: The expedition also took the opportunity to re-film the wreck and survey her using techniques unavailable in 2001. As before, with the exception of the attempted retrieval of the ship's bell, a strict look-but-don't-touch policy was adhered to. The original attempt, sponsored by Paul Allen and using his yacht "Octopus", was abandoned after ten days in September 2012 due to unfavourable weather conditions. In 2015, the same team attempted a second recovery operation and "Hood"s bell was finally retrieved on 7 August 2015. After conservation work, Princess Anne, the Princess Royal, unveiled the bell at the museum on 24 May 2016 – the 75th anniversary of the Battle of the Denmark Strait. The bell was rung eight times in a commemorative service at midday attended by descendants of crew members who died in the battle before being placed in the museum's exhibit on the Battle of Jutland.