Low Risk, Flexibility Drive Type 26 Design
Aviation Week & Space Technology - Defense Technology Edition
Bill Sweetman
Bill Sweetman (Washington)
U.K. takes practical approach to future warship
One of the more innovative features of the BAE Systems Global Combat Ship, formally known to the Royal Navy (RN) as the Type 26, might be its name. It could be argued that it's part of an Orwellian trend toward vague and generic language, but it also (from BAE's perspective) deals with the fact that the meanings of "frigate" and "destroyer" have become confused, mainly because they were historically defined in terms of multi-class fleets that, for most operators, are a thing of the past. There's no point in setting up a terminological barrier to export sales, whether a customer wants to seem powerful (destroyer), frugal (frigate) or peace-loving (patrol ship). The U.K.'s working plan is to build 13 of the new ships to replace the same number of Type 23 Duke-class frigates, which were designed in the Cold War for antisubmarine warfare in the North Atlantic. The number is subject to change because the last Type 23 is not due to be retired until 2036. However, the industry team wants to branch out into the export market, where the U.K. has not been a major player since the last Leander-class frigates were delivered in the 1970s. Originally, the defense ministry planned a Future Surface Combatant fleet in two different classes, one equipped for high-end warfare and a more austere version for general-purpose use - patrol, disaster relief and counter-piracy operations, for example. Following the U.K.'s October 2010 defense review, however, the plan shifted to a single hull design, although not carrying the same equipment. The most important difference will be that eight of the Type 26 ships will carry the Thales Sonar 2087 towed-array antisubmarine sensor, a large, modern and (according to the RN) very capable sonar. These systems will be transferred from the Type 23s that carry them today (the seventh installation was completed earlier this year) to the new ships. The Type 26 has a conventional hull design and is slightly larger than the Type 23, but it expected to require a smaller crew. The U.K. has recognized that the life-cycle cost of a ship is powerfully driven by crew costs, which is why the Queen Elizabeth-type carriers emerged as larger vessels than expected, but with extensive use of automation and automated assistance to the crew. Greater size also means flexibility to accommodate small boats and unmanned surface, air and undersea vehicles. One feature of the Type 45 destroyers and the new carriers is a conscious investment in better accommodation for all the crew, avoiding hot-bunking and housing people in cleanly designed four- or six-berth cabins. The RN has taken some criticism for this approach, but responds that most of its crewmembers acquire skills that are marketable on land, and that comfort has a positive impact on retention rates. (As a writer in the ThinkDefence site comments: "I would suggest those crusty old sea dogs take their nostalgia elsewhere - perhaps they miss weevils and scurvy as well.") The new ship's propulsion departs from RN practice. Defined as Codlog (combined diesel-electric or gas), it will comprise three elements: a set of four high-speed diesel generators; two propeller shafts with integrated electric motors; and a single gas turbine, most likely a Rolls-Royce MT30, geared to both shafts. The diesels - isolated from the hull and shafts to reduce noise transmission to the water - provide efficient and quiet propulsion at patrol speeds up to 18 kt. Diesel-electric drive also eliminates long power shafts and allows the installation to be more flexible. The MT30, with its high power/weight ratio, can be installed aft in the hull and provides a sprint capability to 28 kt. Because the turbine is only used at or near full power, there is no need for a complex recuperative turbine system like the Type 45's WR-21, which is needed for part-power economy. Another factor that makes Codlog attractive is the steady improvement in diesel performance - including power from a given weight and volume. The diesels will most likely come from MTU, part-owned by Rolls-Royce. Weapons will include MBDA's Sea Ceptor anti-air-warfare (AAW) missile, which (like the sonar) will be physically carried over from Type 23s. Sea Ceptor is being pushed ahead rapidly as a retrofit for the Dukes, because the missiles in the current Sea Wolf system are facing a hard life limit. The main AAW sensor will be the BAE Systems Artisan radar - already in service on some RN ships, and also to be retrofitted to the Type 23s and carried over to the new ships. The RN has yet to select a gun for the Type 26, but Oto Melara's 127-mm./64-caliber lightweight gun is a likely choice because of features such as a high rate of fire, the ability to carry multiple types of ammunition that can be selected from one shot to the next, and the availability of the Vulcano extended-range and guided ammunition family. No firm plans have been announced for anti-ship missiles, although the ship's embarked Merlin and Wildcat helicopters will carry MBDA Future Anti-Surface Guided Weapon missiles for use against smaller craft. AW_10_15_2012_p17-501122
Issue: Aviation Week & Space Technology 2012-10-15 Defense Technology edition
Starting Page: 17
Source URL: