Combat applications for waterjet powered ships

By Edward Lundquist at June 22, 2011 15:57
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Third in a series of articles on waterjets in www.maritime propulsion.com

 

Waterjet propulsion for combat ships and craft is a growing trend.  While waterjets have powered small craft for many years, now they are being employed on combatants, including ships as large as the two variants of the U.S. Navy’s littoral combat ship feature waterjets.

 

In many cases, the power is derived from both diesels and gas turbines.  In one unique case, the power drives both waterjets and a screw.

 

South Africa’s 3,590-ton Valour class frigates, built by Blohm + Voss to the MEKO A-200SAN (for South African Navy) design, employs a combination of screws and waterjets, known as CODAG WARP (Combined Diesel and Gas - Water Jet and Refined Propeller) propulsion solution.  A single GE LM2500 gas turbine is combined with a pair of MTU 16V1163 TB93 diesels.  The diesels are each connected to Lips five-bladed controllable-pitch propeller outboard, while the gas turbine is connected to a centerline Lips LJ2 10E waterjet.  The first of four of these ships joined the South African fleet last year.  The Wärtsilä propulsion jets aboard these South African ships are the largest water jets ever built, providing a maximum speed of more than 27 knots. 

The Wärtsilä-Lips LJ210E waterjet is the largest reversible waterjet ever built and is so far unique in its kind. The high speed crash stop installation of this jet reverses within 3 seconds after activation roughly 10,000 gallons of seawater per second, enabling the 3500T vessel to crash-stop from the top speed within three ship’s lengths, according to Wärtsilä representatives. The reversing installation can be fully engaged at the maximum output of the gas turbine by use of hydraulic accumulators giving instant power to activate the balanced crash stop-reversing bucket.

 

The Swedish Visby-class multipurpose patrol combatant is a 620-ton ship with a top speed of 34 knots.  Visby employs a CODOG arrangement comprised of four Honeywell-Vericor TF50A gas turbines and a pair of MTU 16V 2000 N90 diesels, powering a pair of Rolls-Royce Kamewa 125 SII waterjets to deliver 21m460 shp.  The Swedish navy also has waterjet experience with the 420-ton Goteborg class guided missile patrol craft, and other smaller craft.  The four Göteborg class corvettes built by Kockums for the Swedish Navy between 1990 and 1993 were the first vessels in the Swedish Navy to be equipped with waterjet propulsion. 

 

Norway’s Skjold surface effect ship (SES) has a CODOG arrangement with two Rolls-Royce Allison 571-KF9 gas turbines, a pair of MTU 12V183 TE92 diesels, a pair of MTU 6R183 TE52 diesels for auxiliary power, and two Rolls-Royce Kamewa 80S2 waterjets.  Built from composites, the 280-ton Skjold can reach speeds of 55 knots.  Norway has also built a class of SES minehunters and minesweepers built by Kvaerner Mandal.  Larger than Skjold, at 470 tons, but much slower at 13 knots top speed, the Oksoy and Alta class of mine warfare ships have two MTU 12V 396 TE94 diesels ( 4080 hp ), a pair of Kvaerner Eureka waterjets ( rated at  4160 hp ), and two MTU 8V 396 TE54 diesels ( 1880 hp ) for auxiliary power.

The 500-ton ROKN Gumdoksuri-class PKX "patrol killer- experimental" has two MTU diesels and two GE LM500 marine gas turbines, with waterjets, for a max speed of greater than 41 knots.  Pesaka Astana (M) Sdn Bhd is providing the waterjets to the South Korean Ministry of Defence through its South Korean  Daesung Marine Technology Co Ltd (DSMT) subsidiary, under an agreement with Doosan Heavy Industries to manufacture and supply the waterjet components.

Abu Dhabi Ship Building (ADSB) is building six 7233 ft. Baynunah Class corvettes powered by Rolls-Royce Kamewa waterjets for the UAE Navy. It has previously delivered 12 Ghannatha fast patrol boats and four fast supply vessels to the UAE Navy and UAE Coast Guard, all with Rolls-Royce Kamewa waterjets.  ADSB is also constructing 12 fast fighting boats for the UAE Navy, which are powered by Rolls-Royce Kamewa waterjets.

Lockheed Martin has delivered USS Freedom, a semi-planing monohull design, at Marinette Marine in Wisconsin.  Austal USA in Mobile, Alabama has built USS Independence, and all-aluminum trimaran.  More ships are being built at both yards.  Both have diesels and gas turbines, and both employ waterjets.  Both ships displace about 3,000 tons, with up to 4,000 tons fully loaded. 

 

On USS Freedom, two Rolls-Royce MT30 36MW gas turbines and two Fairbanks Morse Colt-Pielstick 16PA6B STC diesel engines are the prime movers, powering four large Rolls-Royce Kamewa waterjets. Four Isotta Fraschini Model V1708 ship service diesel generator sets provide auxiliary power.

 

For USS Independence, two General Electric LM2500 22 MW gas turbines and two MTU 20V8000M90 9100 kW diesel engines are the prime movers, powering four large steering and reversing Wärtsilä-Lips 2 X LJ160E and 2 X LJ150E waterjets.

 

Kamewa waterjets are fitted on have been installed on the Peoples Liberation Army Navy's Type 022 missile craft.  The Type 022 has a Small Waterplane Area Twin Hull (SWATH) wave-piercing catamaran design.

 

Waterjets are also installed aboard the U.S. Navy's experimental high-speed aluminum catamaran X-Craft demonstrator, built by Nichols Brothers Boat Builders, Whidbey Island, WA.  Power is supplied by a pair of MTU 16V 595 engines and two GE LM 2500 gas turbines in a CODOG configuration.  The four high-efficiency Kamewa 125 SII waterjets deliver 50.4MW of power, offering speeds of up to 50 knots.  The 1,100-ton X-Craft is the Littoral Surface Craft-Experimental LSC(X), developed by the Office of Naval Research and known as the Fast Sea Frame Sea Fighter (FSF 1), which has been useful as a surrogate “sea frame” in developing the concept for the littoral combat ship.

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