Love boats and sexy submarines: 7 romantic riverside retreats All you need is love Sweet river cruise Pearl hunters Lighthouse love-in Arctic adventure Picture-perfect Med Underwater snappers This Valentine's Day, ditch the chocolates and try a unique nautical excursion CNN brings you the top 7 dates for adventurous aquatic-lovers Includes chocolate-making cruises and pearl diving courses Beatles fans can stay on converted yellow submarine hotel Editor's note: MainSail is CNN's monthly sailing show, exploring the sport of sailing, luxury travel and the latest in design and technology. (CNN) -- Valentine's Day is about spending quality time with that special someone who floats your boat. And what better way to show your love is deeper than the ocean than by treating your sweetheart to a romantic sea-themed excursion? But if you thought watching sunsets over water was going to cut it, think again. From staying on the Beatles' famous yellow submarine in Liverpool to pearl diving in the Persian Gulf, CNN takes a look at the top seven dates for adventurous aquatic-lovers. All you need is love on a yellow submarine The Beatles may have sung "You can't buy me love," but that doesn't mean you can't buy a romantic getaway on the Fab Four's yellow submarine. Inspired by the submarine that featured in the band's 1968 animated film of the same name, the floating hotel is moored in the pop idols' hometown of Liverpool. The converted narrowboat features a psychedelic lounge adorned with gold Beatles records and the original mod scooter from the 1979 British rock film "Quadrophenia." Read: Fantastic floating hotels for every traveler Film buffs will have extra reason to twist and shout -- the narrowboat also featured in the 1990 Sean Connery thriller "The Hunt for Red October," before its current reincarnation. Chocolate-making cruise From the time of the ancient Aztecs, chocolate has been sending us into raptures of aphrodisiac bliss. But the process of cooking sweet treats can be just as sensual as eating them -- particularly when you're puttering down the Thames in a vintage 1960's boat. Alan Whatley, former chef at London's prestigious Savoy restaurant, shows guests the fine art of creating sumptuous chocolate desserts -- all while meandering through the south England countryside on a 12 meter wooden vessel. Read: Sailing the world's most beautiful lakes Setting sail from Henley-on-Thames, the picturesque three-hour journey offers views quite literally fit for a Queen -- Her Majesty's official home, Windsor Castle, backs on to the river. "It's something a bit different from your standard chocolate in a box," charter manager, Daisy O'Halloran said. You can learn a new skill but you've also got the romance of the river. Persian Gulf pearl diving For hundreds of years, the Persian Gulf has been a rich source of the world's pearls, with divers plunging up to 40 meters below the water to get their hands on the "jewels of the sea." Now adventurous couples can also try their luck, with Bahrain's Al Dar Island offering day trips on traditional wooden sailboats, called dhows. After an onboard history lesson and demonstration, guests use a weighted rope to navigate down to the shallow seabed in search of riches. Once back on deck, they can admire their haul over a lunch of freshly prepared middle eastern dishes. It's different from your standard chocolate box -- you can learn a new skill but you've also got the romance of the river Henley Sales & Charter manager, Daisy O'Halloran "Love has no age, no limit, no death," said 1932 Nobel Prize winning English writer, John Galsworthy. If you want to show your love is forever, the thousand-year-long musical piece playing from London's only lighthouse comes pretty close. Lovebirds can take in glittering views of the city from the lighthouse on the Thames, while listening to a unique composition of ancient Tibetan singing bells. The haunting music, played from loudspeakers, began in 1999 and aims to continue without repetition until 2999. "It's incredibly romantic," said administrator, Victoria Burns. You can daydream together whilst enjoying magnificent views of the City through diamond-leaded windows. Arctic hot tub adventure Scented candles, a hot tub and breathtaking views of the northern lights -- it's not a honeymoon suite, but a unique floating hotel in the Arctic. Introducing Vulkana, a 1950s fishing trawler converted into a luxury spa moored in northern Norway. The 23 meter vessel offers safaris along the dramatic Arctic coastline and boasts a wood-fire sauna, saltwater hot tub and seven-meter diving board for the more adventurous. When not marveling at the snow-capped views from the comfort of a steaming spa, sweethearts can take part in winter activities, inclduing reindeer-sledding and skiing. "There's something spiritual about the boat itself," co-owner Erlend Larsson said. It's had a long life, and many different owners, and all of them have said how safe and calm everybody feels onboard. Read: Sailing the Arctic in fishing boat turned luxury spa Painting the Turkish Riviera Roman general Mark Antony was supposedly so taken with the stunning south coast of Turkey -- known as the "Turkish Riveria" -- he gave it to Egyptian Queen Cleopatra as a wedding gift. Boasting dramatic cliffs perched over the sparkling Mediterranean Sea, it's easy to see why. Hundreds of years later, creative couples can also capture the scenes that so besotted Anthony -- in an island-hopping painting course. Setting sail from the small fishing town of Kas in south west Turkey, the tour winds past sun drenched islands before arriving at the ancient sunken city of Kekova. There, artistic lovebirds can sketch the 2nd Century ruins from the comfort of their wooden sailboat. Read: Dangling on the edge -- Life of a daredevil photographer Tropical underwater photography It's the enduring problem of holidayers: the photos never quite live up to the reality. And if you're going to take your beloved on an expensive tropical getaway, you may as well capture it properly. Thailand island Koh Lanta, on the south west coast, offers vibrant coral reefs, thriving marine life and sparkling clear waters. And perhaps the best way to capture this spectacular underwater world is with a deep sea photography or video course. Divers are quipped with specialist underwater cameras and taught everything from spotting unusual aquatic animals to creating a dramatic composition.