USS America Powered by GE Gas Turbines

By Eric Haun at April 17, 2014 15:44
Filed Under: Hybrid system






U.S. Navy amphibious assault ship USS America (LHA6) recently complete Huntington Ingalls Industries (HII) acceptance trials in the Gulf of Mexico near HII’s Pascagoula, Mississippi shipyard.

LHA6 is the fourth U.S. Navy ship to bear the name America, and is the first of the Navy’s new America-class amphibious assault ships.

America was built in Pascagoula, Miss. by Ingalls as part of a $2.4 billion fixed-price incentive contract for the detailed design and construction of LHA-6. The production decision was made in January 2006 and construction of LHA-6 began in December 2008.

GE Marine was chosen to provide the ship’s hybrid mechanical-electric propulsion system consisting of two LM2500+ gas turbines and two, 5,000 horsepower auxiliary propulsion motors, which allows the ship to reach speeds in excess of 20 knots.

“The selection of the LM2500+ gas turbines offers propulsion commonality for this first-in-class ship with the U.S. Navy’s USS Makin Island LHD 8 amphibious assault ship. The LHD 8 was the first U.S. Navy ship to use this hybrid propulsion system configuration, as well as the first military application of the LM2500+ gas turbine,” said Brien Bolsinger, Vice President, Marine Operations, GE Marine, Evendale, Ohio.

According to GE Marine, the hybrid propulsion system enables the ship's propellers to be driven either by the gas turbines or by the electric motors, which are powered from the ship service electrical system. The hybrid propulsion system allows the ship to operate in a more fuel efficient mode throughout its speed range. The LM2500+ gas turbines were manufactured at GE’s Evendale, Ohio, facility.

America-class ships are 844 feet long,106 feet wide and displace 44,971 long tons, and can accommodate a crew of 1,204 (102 officers) and 1,687 troops.

The keel-laying ceremony was held on July 17, 2009 with delivery originally planned for August 2012. The ship was launched on June 4, 2012, and christened on October 20 the same year. LH6 is scheduled for delivery in spring of 2014, and will be homeported at Naval Base San Diego.

“The newest America will provide presence and power projection as an integral part of joint and multinational maritime expeditionary forces,” the Navy said. “The ship will support Marine Corps aviation requirements across a wide spectrum of operations, from small-scale contingency operations as the centerpiece of a forward-deployed expeditionary strike group, to forcible entry missions in a major theater war.”

LHA 6 also has an extended hangar deck with two higher hangar bay areas, each fitted with an overhead crane for aircraft maintenance, the Navy explained. LHA 6 offers increased aviation fuel capacity, stowage for aviation parts and support equipment and will be able to embark and launch the MV-22 Osprey tilt-rotor aircraft, cargo and attack helicopters, the AV-8B Harrier and the short take-off vertical landing (STOVL) variant F-35B Lightning II Strike Fighter.




Photos courtesy GE Marine

CIC Results Underline Propulsion/Power Problems

By Eric Haun at April 03, 2014 15:04
Filed Under:


Photo: Paris MoU



Last summer, the maritime authorities of the Tokyo and Paris MOUs on Port State Control (PSC) announced the joint Concentrated Inspection Campaign (CIC) to address compliance with aspects of SOLAS Chapter II-1/Construction – Structure, Subdivision and Stability, Machinery and Electrical Installations.

In launching the inspections initiative, which ran from September 1 to November 30, 2013, the MoUs said, “The scope of the CIC is the safety of propulsion and auxiliary machinery, especially the working order and maintenance of the main engines, auxiliary engines, auxiliary equipment and their related alarm systems.”

As results are processed, both the Paris and Tokyo MoUs are finding that maintaining propulsion and auxiliary machinery is an issue for many ships – perhaps to a greater degree than expected.

The Paris MoU’s preliminary CIC results show that a staggering 41% of all detentions directly resulted from deficiencies related to propulsion and auxiliary machinery, listing main problem areas as the main engine propulsion, cleanliness of the engine room and emergency source of power/emergency generator.

Preliminary CIC results from the Tokyo MoU similarly found that the most significant deficiencies found during the campaign were related power and propulsion machinery: emergency source of power and emergency lighting 25.4%, main and auxiliary boilers and boiler feed systems 17.3%, protective arrangements for machinery to minimize danger to persons with regard to moving parts, hot surfaces, electrical shock or other hazards 15.1% and cleanliness of the engine room 15%.

“Given the fact that 25% of the detentions were CIC-topic related during the campaign period, the preliminary results highlight that propulsion and auxiliary machinery installations on board remain a challenge to keep under control," the Tokyo MoU said.

In previous years, propulsion and machinery installation issues accounted on average for just 7% of the total number of deficiencies within the Tokyo and Paris MoU´s, ranking sixth in comparison with all the deficiencies by category.

And according to the Paris MoU, more than half (54%) of all CIC-topic related detentions involved ships of 20 years or more: The detention rate for these ships was 3.6%, compared to the overall rate 1.8%.

“This outcome illustrates that wear and tear of propulsion and auxiliary machinery remains an issue which should be adequately addressed by ship owners,” said Richard Schiferli, Secretary General of the Paris MoU on PSC.

The campaign results will be analyzed in greater detail before presentations to the PSC, after which a full report will be submitted to the International Maritime Organization (IMO).

New Medium-Speed Flexible Diesel Engine from Wärtsilä

By George Backwell at March 29, 2014 00:16
Filed Under: Marine Diesel Engines

The new Wärtsilä 46DF engine has been specifically developed for the high-output market and is fuel flexible as well as power flexible with 1045 kW or 1145 kW cylinder power options.

Compactness and reduced weight are the key attractions of the medium-speed engine, giving ship designers the option of increasing a new vessel’s revenue-earning capacity to get the most efficient propeller speed through mechanical  (reduction gearing), or through diesel-electric transmissions.

With the cruise ship, ferry,  LNG carrier and offshore vessel markets for this type of engine in mind, the 46F engine design is based on the well proven Wärtsilä 46F engine, popular since the early 2000s, but with the advantage of being able to use natural gas, heavy fuel oil (HFO), or marine diesel oil (MDO) bunker fuel.  

Engine details
The Wärtsilä 46DF extends Wärtsilä’s dual-fuel engine family by covering the power range from 6.2 MW to 18.3 MW at 600 rpm.

    •    Cylinder bore 460 mm
    •    Piston stroke 580 mm
    •    Cylinder output 1045/1145 kW/cyl
    •    Engine speed 600 rpm
    •    Mean effective pressure 21.7, 23.8 bar

Wärtsilä 46DF engine: Image courtesy of Wärtsilä
 

Fuel flexibility & automation
Wärtsilä’s proven dual-fuel technology enables a choice between gas and liquid fuels, with a switch between the two according to cost, availability, and local environmental regulations. Wärtsilä  say that the switch between fuel types is made without loss of power or speed. The engine automation adapts automatically to the relevant fuel selection, both in normal and emergency modes.

In gas mode, the natural gas is fed to the engine at low pressure. This facilitates a simpler and space saving engine room configuration, while providing easier and faster maintenance activities.

The engine’s gas piping is double-walled as standard, and the advanced integrated automation system enables enhanced safety and local monitoring, which leads to safer and more reliable operations under all conditions.The complete built-in automation minimizes the need for external controls, thus saving engine control room space.

The Wärtsilä 46DF is designed for a broad range of marine applications and the engine can be optimized for constant speed diesel electric operation. It also meets the need for direct drive main engine propulsion, operating at either constant speed or along a combinator curve.

Fuel savings for LNG carriers
For LNG carrier applications, the engine builders say that the 46DF can offer fuel savings of as much as 20 tons/day compared to the first introduced DF engines. With up to 14 fewer cylinders installed, the overall lifecycle installation costs are significantly and positively impacted by roughly 1000 USD/day.

Exhaust gas emissions
When operating in gas mode, the Wärtsilä 46DF engine is already compliant with IMO Tier III regulations without any secondary exhaust gas purification systems. In liquid fuel oil mode, the Wärtsilä dual-fuel engines are fully compliant with the IMO Tier II exhaust emission regulations set out in Annex VI of the MARPOL 73/78 convention.

 Source: Wärtsilä

 

 

 

High-Tech Propulsion for Russia's Newest LNG Carrier

By Eric Haun at March 28, 2014 17:23
Filed Under: Hybrid system, LNG fuel, MAN Diesel&Turbo, Propulsion systems


Photo: MAN Diesel & Turbo

Russia’s largest shipping company, Sovcomflot Group, recently took delivery of a newbuild LNG carrier from STX Offshore & Shipbuilding. The 300m vessel, Velikiy Novgorod, is impressive for a number of reasons: it is Arctic ice-classed and has a total gas load capacity of 170,200m3, but the ship is significant most notably for its diesel-electric, dual-fuel propulsion system, which consists of two MAN 8L51/60DF and two MAN 9L51/60DF engines, offering a total rated power of 34 MW.

MAN Diesel & Turbo’s German-built, low-emission propulsion system enables the ship to burn both gas and fuel oil, supplying power to electric motors. This offers a great deal of efficiency, especially when running in gas mode, while also providing a high degree of flexibility and redundancy.

“Key drivers for dual-fuel diesel-electric (DFDE) are its fuel economy and environmental friendliness, its reliability and flexibility due to multiengine concept and safety aspect due to low pressure gas injection, as well as its flexibility in terms of fuel selection (Boil of Gas, MGO, HFO),” a spokesperson from MAN Diesel & Turbo said, adding that these advantages have helped DFDE ship propulsion become “by far the leading concept used by LNG industry.”

The multiengine plant inherently includes a built-in backup, not only offering reliability, but also full maintainability at full service speeds and any time throughout the ship’s voyage.

MAN’s spokesperson added, “DFDE propulsion concept is leading to an LNGC with low complexity, easy to operate, highest efficiency and level of safety while meeting future IMI Tier III emission standards already today.”

In accordance with emerging trend toward dual fuel and alternative fuel LNG carriers, new vessel Velikiy Novgorod is the first ship in a series of five to be built by South Korea’s STX Offshore & Shipbuilding. The ship will reportedly operate for Gazprom under a long-term time-charter agreement with Sovcomflot, while the second ship is slated for delivery in fall 2014.

MAN Diesel & Turbo said the delivery of the LNG carrier newbuilding orders fall under its strategy of expanding its environmentally friendly dual-fuel engine technology into the marine sector, noting promising opportunities ahead in the LNG market. Factors such as rising costs of liquid fuel, reduction of gas prices to due shale gas, lower CO2 and NOx emissions when burning gas, exit out of nuclear power plants and entry into gas power plants have led the company to more actively follow pursuits in the LNG market.

“Gas consumption is on the rise,” MAN’s spokesperson said, “demand for LNG carriers and LNG propelled vessels will continue to grow.” And as the world demand of LNG grows, and more LNG terminals are being planned and constructed, the demand for transportation of LNG worldwide will increase accordingly.

While working on the Sovcomflot project, MAN Diesel & Turbo utilized its experience from working on its first 51/60DF reference project, delivered in 2010 to Spanish shipping line Elcano. The Castillo de Santisteban, which features five MAN 8L51/60DF units, has been operating globally since August 2010 without one day off-hired time on worldwide LNG trades, operating everyday with full propulsion power available, MAN said.

“The experiences won by running engines on board a LNG carrier in daily operation gave us valuable input regarding life time and operating sequences,” the MAN spokesperson said. “The environmental conditions were giving us a great feedback as they vary much more as the powerplant references we have in place. For the Sovcomflot vessels we could also introduce the so called ‘fuel sharing’ where the engines can run partly on gas as fuel and partly on HFO.”

 


Photo: MAN Diesel & Turbo

Marine Engine Drive Couplings or Keeping Pliable Offshore Brazil

By George Backwell at March 22, 2014 00:32
Filed Under: drive systems

Drive coupling specialists Vulkan, based in Germany, is supplying both fixed and flexible drive couplings to Brazil’s home-built burgeoning offshore energy sector, and interestingly is also involved in a project to develop a nuclear-powered submarine propulsion system for the Brazil Navy.
 
The diesel engine beats to the sound of a pulsating drum in its cycle giving rise to shaft vibration. Secondly, slight misalignments, in connected drive shafts also need to be smoothed out, and to achieve this, flexible couplings incorporate rubber-like polymer subrstances in their design – elastomers.

Vulcan explains that compound research in its R&D facility with highly specialized vulcanization technology has led to the development of an elastomer with considerably higher power density  – the 'Acotec' compound. This new compound distinguishes itself from other conventionally used materials not only through its enhanced tensile and tear strength and increased ultimate elongation, but also through a high thermal resistance and reduced ageing.

Vulkan’s latest project was to supply highly flexible couplings for Caterpillar gensets and electric motors, as well as torsionally rigid couplings for the waterjets of six drillships built for Petrobas in a Brazilian shipyard.

Image courtesy of Vulkan

Nuclear-powered submarine project
Brazil’s ambitious plan is to have six nuclear-powered submarines out of a total fleet of no less that twenty in the long term.  The Brazil Navy is tasked to protect the nation’s vast subsea energy resources in fields located up to 350 kilometres off the coast and at a depth of over 3,000 meters. Preliminary estimates suggest that up to 100 billion barrels of oil are to be found there.

The planned nuclear submarine will displace 6,000 tonnes and be 96.6 meters in length, with construction planned to take eleven years. It will be driven by a nuclear reactor developed at the Marine Research Centre Aramar.

A land prototype for the entire drive of the nuclear submarine is currently under construction, of equal size to the drive to be built later. Once this test phase has concluded, the entire submarine will be completely assembled for testing purposes in a multiple-story building. For the drive test rig, Vulcan says it has delivered in co-operation with its Brazil and Italy subsidiaries a RATO S 731 coupling and the elastic mounts.

 

LNG Powered Tugs Ordered in China

By Eric Haun at March 19, 2014 15:43
Filed Under:

Image: Rolls-Royce

Rolls-Royce announced today an order from Chinese state oil company CNOOC to power Asia’s first gas powered tugs. The order includes two tugs to be built at the Zhenjiang shipyard in Jiangsu, China, with an option for two additional vessels.

This order follows the construction of Borgøy and her sister vessel, the world’s first LNG powered escort tugs (also powered by Rolls-Royce), completed in 2013.

According to Rolls-Royce, each newbuild tug will feature (like Borgøy) a pair of Rolls-Royce Bergen C26:33L9PG engines fueled purely by liquefied natural gas (LNG). Rolls-Royce also said power and propulsion systems package for each tug includes a pair of Rolls-Royce US 205 CP azimuth thrusters to ensure the tugs have rapid maneuvering and strong bollard pull capabilities.

“This order is highly significant for Rolls-Royce, CNOOC, and Zhenjiang shipyard and marks a new era for tug boat propulsion technology in China, an increasingly important market for the marine industry,” said Neil Gilliver, Rolls-Royce, President – Merchant. “Rolls-Royce is proud to be selected to power Asia’s first pure gas powered tug and to play a pivotal role in the state's focus on reducing emissions along the coasts and inland waterways.”

Gas is increasingly being used as a maritime fuel thanks largely to its environmental and financial benefits. The trend seems likely to grow in the tug market, especially when considering their primary areas of operation: near shore, where environmental regulations are most stringent and LNG bunkering is most widely available. And as regulations become even more demanding, it is expected that orts will opt for the clean, lower cost and smoke-free fuel to power tugs.

Rolls-Royce gas fuelled Bergen engines meet IMO Tier II and Tier III regulations as well as US Environmental Protection Agency rules on NOx, with a 25 percent reduction in CO2 emissions, a 80-90 percent reduction in NOx emissions and a virtual elimination of SOx emissions and particulates.

The new gas powered tugs will also feature improved fuel consumption, reduced lube oil consumption and lower maintenance costs than traditionally powered tugs.

Gilliver added, “I am convinced that with the growing popularity of LNG as a marine fuel, more operators will soon begin to opt for a cleaner, lower cost and smoke-free fuel solution to power their tugs. This order will be one of many more to come.”


M/T Borgøy

What fuel will ocean-going ships be burning 16 years down the road?

By George Backwell at March 14, 2014 22:23
Filed Under: Fuels & Lubes

Heavy fuel oil will remain the main fuel for deep sea shipping in year 2030 indicates new research from Lloyd’s Register and University College London’s Energy Institute. In a complex study involving many inter-related factors,  ‘Global Marine Fuel Trends 2030’ (GMFT 2030) limits itself to the container ship, bulk carrier/general cargo and tanker (crude & chemical/products) sectors which represent about 70% of the shipping industry’s fuel demand.

VLCC: File photo

Marine fuels considered:
Ranged from liquid fuels used today (HFO, MDO/MGO) to their bio-alternatives (bio-diesel, straight vegetable oil) and from LNG and biogas to methanol and hydrogen (derived both from methane or wood biomass) were included in the study.

Engine technologies
Included were 2 or 4-stroke diesels, diesel-electric, gas engines and fuel cell technology. Since the uptake of certain fuels is influenced by them, a wide range of energy efficiency technologies and abatement solutions (including sulphur scrubbers and Selective Catalytic Reduction for NOx emissions abatement) compatible with the examined ship types were included in the modelling.

Three scenarios applied
Shipping is the enabler of world trade – if world trade grows then so will seaborne tonne miles of cargo. The Global Merchant Trends 2030 report issued last year indicates we can expect strong growth for shipping. With emissions regulations and rising energy costs, shipping decision makers will benefit from a clearer understanding of the potential scenarios for marine fuel demand. These were:

  1. Status Quo – The world will continue its current growth momentum with some booms and busts over the next twenty years.
  2. Global Commons – A shift to concern over resource limitation and environmental degradation will see a desire for a more sustainable world being developed and fairness in wealth distribution. Governments will find common ground and accelerated economic growth, within a framework of sustainable development, which will follow.
  3. Competing Nations – States act in their own national interest. There will be little effort to forge agreement amongst governments for sustainable development and international norms. This is a self-interest and zero-sum world with a likely rise in protectionism and slower economic growth.

Brief conclusions: Fuel mix in 2030

  • Heavy fuel oil (HFO) will still be very much around in 2030, but in different proportions for each scenario: 47% in Status Quo, to a higher 66% in Competing Nations and a 58% share in Global Commons, the most optimistic of scenarios for society. A high share of HFO, of course, means a high uptake of emissions abatement technology when global emissions regulations enter into force.
  • The declining share of HFO will be offset by low sulphur alternatives (MDO/MGO or LSHFO) and by LNG, and this will happen differently for each ship type and scenario. LNG will reach a maximum 11% share by 2030 in Status Quo.
  • Interestingly, there is also the entry of Hydrogen as an emerging shipping fuel in the 2030 Global Commons scenario which favours the uptake of low carbon technologies stimulated by a significant carbon price.


To download a PDF of the report go to www.lr.org/gmft2030, hard copies can be ordered from the Lloyd’s Register Webstore at www.webstore.lr.org


 

 

Wärtsilä’s New Inline Scrubber System

By Eric Haun at March 14, 2014 11:46
Filed Under: New Technology, Scrubbers

Wärtsilä said its new inline scrubber system offers a number of “notable benefits” over conventional exhaust gas cleaning systems. Already with several ships in line for installation, the company says its new product, saves space, lowers cost and eases installation.

Important for all vessels, but particularly for smaller vessels and retrofit projects, space is of chief concern when considering engine room configuration. Add after-treatment products such as scrubber systems into the mix, and space becomes an even greater priority.

Sigurd Jenssen, Director, Exhaust Gas Cleaning, Wärtsilä Ship Power, said, “Space availability is a challenge that makes it difficult for many vessels to have exhaust gas cleaning systems installed.” That’s why Wärtsilä has placed a great deal of emphasis on compactness when designing its new inline scrubber system, which was engineered to conserve considerable (and precious) space. The company said this has already generated a lot of attention from owners and operators to its new product.

And for additional advantages, Wärtsilä claims lower cost structure of the new design offers CAPEX benefits. With only one scrubber system per engine, installation can be performed faster, consequently reduces the out-of-service time for the vessel and improving operational flexibility.

The inline scrubber system operates as a conventional Wärtsilä open loop scrubber system, but has three water inlets in the main body of the scrubber, as opposed to two in the conventional system. The exhaust flows enter from the bottom and exits at the top, with water being sprayed in three stages in a counter flow to the exhaust. A Wärtsilä designed water trap prevents the scrubbing water from entering the engine. The inline configuration can be offered on the hybrid scrubber system as well.

With a contract signed in June 2013 and installation slated for this month at FaYard in Denmark, Color Line’s high speed ferry SuperSpeed 2 will be the first vessel to utilize the new Wärtsilä inline scrubber system. The vessel, which sails twice daily between Larvik, Norway and Hirtshals, Denmark, has limitations on the available space in the funnel, Wärtsilä  said, thus making its new system a practical option.


Photo: Color Line’s SuperSpeed 2

Wärtsilä also announced additional contracts signed in September 2013 for the fitting of the new inline scrubber system to three other Color Line vessels.


The new inline scrubber system from Wärtsilä

Propeller Shaft Seals of Approval for Two Wärtsilä Systems

By George Backwell at March 08, 2014 04:10
Filed Under: Propulsion systems

Ships with Wärtsilä’s Airguard and Oceanguard propellor shaft seals have no need to change from mineral oil to a bio-degradable lubricant (formally ‘an Environmentally Acceptable Lubricant’) when they're in U.S. waters as these seals meet Vessel General Permit (VGP) requirements. How these particular propeller shaft seals comply, and more about these newish VGP amended regulations follows:


Seals,bearings and stern tube arrangement: Image courtesy of Wärtsilä

No oil-to-sea interface
Wärtsilä explain that Airguard is suited for merchant ship stern tube and thrusters, and Oceanguard for cruise, ferry and offshore stern tube, thruster and electric pod face type sealing. 

The Airguard and Oceanguard sealing systems have been designed with no oil-to-sea interface (the essential point): an air chamber or separation space within the seal captures any water or oil leakage, which is then transferred to inboard tanks for monitoring and further treatment. This stops oil drips or leakage into the sea. In the case of system failure, both systems also prevent any oil leakage. The manufacturers say that these seals are also designed to withstand abrasive waters and are compliant with all anti-pollution requirements.

Shaft seals and US Vessel General Permit (VGP)
The revised VGP came into force on 19 December 2013 and applies to non-recreational vessels that are 79 feet (24.08 meters) and greater in length in US waters. For these vessels, the VGP requires environmentally acceptable lubricants (EALs) to be used in all applications that have the potential for an "oil-to-sea" interface (which, as mentioned above, Airguard and Oceanguard seals do not have). The VGP states that oil-to-sea interfaces include any mechanical or other equipment where seals or surfaces may release small quantities of oil into the sea.

The most relevant components are the stern tube, rudder bearings, CP propellers, thrusters and fin stabilisers. However, any ship components that can potentially cause the leakage of lubricants into the sea are in principle to be considered according to the VGP.

Although environmentally preferable, EALs may have some major disadvantages. The most important one, according to classification society DNV GL, is that many conventional rubber (seal) materials are not compatible with the new EALs. Such lubricants will also absorb more water than mineral oils, so water control (i.e. sticking to the recommendation of the EAL supplier) becomes important to maintain lubrication capacity and keep the risk of corrosion and bacteria growth under control. Understandably, technical superintendents will rejoice if they have in place one of the Wärtsilä propeller shaft seals mentioned here.

For detailed information on the revised VGP visit:http://1.usa.gov/1diKHeL

Water Jets Bring Safety for Offshore Wind

By Eric Haun at March 07, 2014 11:32
Filed Under: Offshore, Workboats

Rolls-Royce said today in a press announcement that it will supply water jets for three wind farm support vessels, (one 24-meter and two 26-meter aluminum catamarans) to be built by South Boats IOW for the offshore wind transfer vessel operator Seacat Services.

Rolls-Royce labeled the contract as “one of the biggest orders made for wind farm workboats,” and all three newbuilds will feature two Rolls-Royce 56A3 stainless steel water jets as well as Rolls-Royce’s new compact control system tailored to suit owners’ requirements and reduce build/installation times.

The new wind farm workboats will include MTU 12V 2000 engines which will power the catamarans to speeds of up to 30 knots. Once in operation, the catamarans will be used for people and cargo transfers to the growing number of offshore wind farms around the coast of Europe.

When factoring the water jets’ properties into the vessels’ overall design, the propulsion system contributes a safety element needed especially when transferring crew and equipment onto turbine structures. According to Rolls-Royce, “water jet technology offers a combination of speed, efficiency and excellent maneuverability for these vessels, which will regularly operate in challenging sea conditions with strong winds and currents.”

“Reliability and performance are of utmost importance in our industry and are how all vessels are measured, which is why we choose Rolls-Royce water jet units,” said Ben Colman, Sales & Marketing Manager, Alicat Workboats Ltd. & South Boats IOW Ltd., “With the A3-series we have found excellent performance with speeds higher than predicted with excellent fuel efficiency as a result.”

Coleman mentioned that the A-3 series’ reliability has led his company to fit some 20 Rolls-Royce water jet units over the last few years.

 


Image courtesy Rolls-Royce

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