April 12, 2005
Austal hands over Benchijigua Express
Handed over to Fred. Olsen S.A. today by West Australian shipyard Austal, the 127 meter Benchijigua Express is the world's largest all-aluminum ship. It also provides a preview of the trimaran hull concept on which is based the U.S. Navy LCS being developed by the team led by General Dynamics,
Austal says the vessel is "quite simply the most significant vessel to arrive on the fast ferry stage and is set to allow fast sea transportation to improve and open up new markets beyond the ability of existing fast ferry design for both commercial and military operators."
Fred. Olsen, S.A. pioneered the use of large high-speed ferries in the Canary Islands and currently carries almost three million passengers, half a million cars and a quarter of a million cargo vehicles per year.
Since 1999, the company has been operating large fast catamarans and while happy with the results, the company identified some limitations in terms of capacity and especially passenger comfort when operating in rough seas.
This led to the conclusion that further research was needed in order to develop a new concept for high-speed vessels, combining the softer roll of monohulls with the low resistance, very good stability and carrying capacity of catamarans.
With these objectives in mind, Fred. Olsen, S.A. and Austal cooperated on an extensive program of research, tank testing and analysis, firstly to develop a new design and then ensure it would meet Fred. Olsen, S.A.'s requirements in an efficient and cost-effective manner.
The result is what is properly described as a slender stabilized monohull, but is more commonly referred to as a trimaran.
Austal Chairman John Rothwell, is confident the superior seakeeping performance of the trimaran will provide significantly enhanced levels of comfort compared to the Fred. Olsen's existing fast ferries along with noticeably higher levels of operability.
"Studies based on actual sea conditions found in the Canary Islands enabled Austal to accurately model the vessel's performance on each leg of the proposed route," says Rothwell. "The final report showed the trimaran would offer a 26 percent improvement in operability compared to existing hullforms."
"The characteristics of this new vessel, with a length of 126.7 m and beam of 30.4 m, will improve overall efficiency in terms of passenger capacity, deadweight and freight lane meters by more than 35 per cent," says Fred Olsen. Jr., Chairman of Fred. Olsen S.A., adding that "passenger comfort will increase by 25 percent to 40 percent depending on the routes we operate."
Sea trial successes--and challenges
Initial full power sea trials in conditions of up to four meters significant wave height and 45 knots wind speed confirmed Austal's confidence in the 127 m vessel. Whilst the vessel met the key contract performance requirements it, most importantly, also demonstrated the trimaran's ability to exceed the operability and comfort levels of existing large catamaran designs at the upper end of the weather spectrum.
Two unforeseen challenges were encountered during the sea trials. The first was the failure of the composite ride control surfaces initially supplied. An investigation is currently underway to determine the cause of this failure. Permanent replacement metal alternates have been supplied and fitted.
Secondly, while the trials conducted at full speed in sea conditions of up to four metres significant wave height and 45 knot winds confirmed the trimaran's superior seakeeping and habitability, they also revealed that this capability could be improved in these and even more onerous conditions, with improvements to the software and hardware controlling the steering and ride control surfaces. With the cooperation of the customer Austal has now developed these items in conjunction with additional sea trials.
During sea trials with operating ride control Benchijigua Express achieved a speed of 40.4 knots carrying a deadweight of 500 tonnes.
Austal Chairman Rothwell commented: "Following an unprecedented five year program of research and development we are delighted to see this new fast ferry design exceeding our expectations. Having tested the vessel in conditions in which most current generation high speed vessels would have ceased operations, we recognized the opportunity to further improve our trimaran technology to deliver our customer and the ferry market a proven solution for routes beyond the ability of existing fast ferry designs".
Austal is now working closely with Flag States to achieve operability certification for the Auto Express 127 trimaran in 4 metres, or more, significant wave height.
With a capacity to carry 1,350 passengers and 341 cars the ferry will operate between Los Christianos in the south of Tenerife and the islands of La Gomera and La Palma.
Arranged in two separate engine rooms in the trimaran's central hull are four MTU 20V 8000 diesel engines. Each is rated at 8,200 kW which will be upgraded to 9,100 kW during the first quarter of 2006.
The diesels in the aft engine room each drive a Kamewa 125 SII steerable waterjet from Rolls-Royce while the two forward engines deliver their combined power to a Kamewa 180 BII booster waterjet.
Each of the three drivelines features Renk transmissions, with lightweight composite shafts fitted between the waterjets and gearboxes and on the output shaft of the forward most engine.
The exhausts for the outboard aft engines are dry type exiting the vessel at the bridge deck through a funnel casing. The inboard engines have a wet exhaust system exiting between the hulls.
"Even though the trimaran is very much larger in terms of both length and capacity, the challenge for Austal has been to deliver maneuevring characteristics equivalent or better than Fred. Olsen S.A.'s existing vessels," says James Bennett, Austal's Technical Manager.
Bennett says this has been achieved by fitting two Ulstein Aquamaster UL601 azimuthing bow thrusters supplied by Rolls-Royce.
"The ability to synchronize the thruster and waterjet control systems will give the vessel's Captain excellent control to ensure fast, efficient and safe operation in port," says Bennett. In open water the electrically driven thrusters are retracted into the hull to reduce drag, he adds.
With electrical power provided by the vessel's diesel generators the bow thrusters can be integrated into the harbor mode of the waterjets to provide a single point of control for both systems. Alternatively, the Captain can choose to operate the bow thrusters independently.
Keeping maintenance costs to a minimum, the bow thrusters are designed to be lifted out onto the vehicle deck whilst the vessel remains afloat for inspection.
Vessel motions are controlled by the movement of three sets of control surfaces fitted to the center hull. The system consists of a single T-foil forward, two anti-roll fin stabilizers at about two-thirds of the length aft and finally two interceptors at the transom.
Benchijigua Express has a transverse metacentric height similar to a monohull ferry and therefore is fitted with a ballast and heel control system consisting of two ballast tanks and two heel control tanks.
Both sets of tanks are designed to be filled as the vessel slows down on entering port. The tanks can be filled in about 5 minutes. The ballast tanks have been designed to cause parallel sinkage to lower the vessel into the water increasing the waterplane area and therefore the transverse stability. Each heel control tank is connected to two transfer pumps that can rapidly pump water from one tank to the other. The pumps are run from a variable speed drive, which in turn receives signals from a PLC based control system.
With the tanks filled upon arrival the control system senses any change in heel angle during loading and unloading and rapidly transfers ballast to maintain a level deck. When the vessel is loaded with vehicles and passengers the ballast and heel control tanks are pumped out.
Film, not paint
Close inspection of the eye-catching Fred. Olsen Express livery of Benchijigua Express reveals the hull and superstructure are not in fact protected by paint but by a self adhesive film.
Orca Marine's Offshore Film is a pure vinyl product that protects a surface much in the way paint works. However, the film has an expected lifespan of 10 to 12 years service depending on conditions. For conventional paint coatings in a marine environment 3 to 5 years is relatively normal under comparable conditions. The use of protective film on areas above the waterline normally covered by paint is expected to deliver substantial economic benefits thanks to a significant reduction in work and time involved in application and a reduction in routine maintenance costs by up to 50 percent.
As a further item of interest to this already milestone project, Fred. Olsen, S.A. had a requirement that the waterjets could be accessed for inspection and replacement of the thrust bearing given the lack of local shipyard resources suited to a 127 m x 30 m vessel and the potential for this relatively minor servicing problem to interrupt operations.
A transportable cofferdam or caisson matching the unique shape of the center hull's transom has been designed, built and tested creating a dry working environment around and under the waterjets. Operated by air supplied by the vessel and with customized mounting points on the ferry it has proven to be a straightforward and successful solution to the original concern.
"While the Auto Express 127 trimaran Benchijigua Express sets new industry standards for commercial vessel performance, its design and construction are both soundly based and the technology has been identified as having military application", says John Rothwell.
A team led by General Dynamics that includes Austal has been selected to provide a trimaran hullform based design for the US Navy's Littoral Combat Ship (LCS) project. A decision on the option for the construction of an initial two 127 m vessels is expected in October 2005 with a potential 60 of these combat ships built over a forecast 15 year period for future Navy requirements.
Austal has already built two high-speed catamarans of over 100 me in length. One of these, the 101 m WestPac Express, has already proved successful in carrying out Theatre Support type duties for the U.S. Marine Corps in the Western Pacific region.
Two further 105 metre catamarans are currently under construction at Austal's Mobile, USA shipbuilding facility.
Length overall: 126.7 m
Length waterline: 114.8 m
Beam moulded: 30.4 m
Hull depth molded: 8.2 m
Hull draft (maximum): 4.0 m
Deadweight (maximum): 1,000 tonnes
Vehicles: 341 cars or 450 truck lanes meters and 123 cars
Axle loads:15.0/12.0 tonnes (dual/single axles) on central lanes
9.0/12.0 tonnes (dual / single axles) outboard
1.0 tonnes on forward ramps
0.8 tonnes on mezzanine decks
Vehicle deck clear height (max):4.60 m
Speed:40.4 knots, 500 dwt, 32.8 MW
Fuel: 145,000 liters
Fresh water: 7,000 litres
Black and gray water: 7,000 liters
Lube Oil: 2 x 600 liters
Hydraulic Oil: 2 x 600 liters
Sludge: 1,000 liters
Main engines: 4 x MTU 20V 8000; 8,200 kW at 1,150rpm each
Gearboxes: 2 x Renk ASL65; 1 x Renk ASL 2X80
Waterjets: 2 x Kamewa 125 SII; 1 Kamewa 180 BII
Azimuthing bow thrusters: 2 x Ulstein Aquamaster UL601
Generator sets: 4 x MTU 12V 2000 M40 540 kW each.
ClassificationGermanischer Lloyd X100A5, HSC-B OC3 High Speed Passenger/Ro-Ro Type XMC, AUT.