Trimaran to Dominate High Speed Sea Transport

Larger than any existing diesel-powered fast ferry - catamaran or monohull - "Benchijigua Express" is world's largest all-aluminium ship and first commercial trimaran with significant commercial and military applications.

With the handover completed on April 13, the new 127 metre, Auto Express 127 trimaran built by the West Australian shipyard, Austal, for Fred. Olsen, S.A. 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.

When Austal and European ferry operator Fred. Olsen, S.A. signed a contract in Santa Cruz de Tenerife in May 2003 to build a second high speed vehicle–passenger ferry, it was the signal to start constructing not just another ferry but also the end to an exhaustive design, research and development programme with origins dating back as far as early 2000, to create a new hullform which would provide a quantum improvement in the performance and operability of large fast ferries.

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 it 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 programme 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 correctly described as a slender stabilised monohull, but more commonly referred to as a trimaran.

Austal Chairman, Mr John Rothwell, is confident the superior seakeeping performance of the trimaran will provide Fred. Olsen, S.A.'s passengers with significantly enhanced levels of comfort compared to the company’s existing fast ferries and is also expected to result in 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. The final report showed the trimaran would offer a 26% improvement in operability compared to existing hullforms," he explained.

Fred. Olsen, S.A. Chairman, Mr. Fred Olsen Jnr. said that through the close cooperation with Austal a highly versatile vessel with many improvements over his current fast ship fleet has been developed.

"The characteristics of this new vessel, with a length of 126.7 metres and beam of 30.4 metres, will improve overall efficiency in terms of passenger capacity, deadweight and freight lane metres by more than 35%. At the same time passenger comfort will increase by 25% to 40% depending on the routes we operate", Mr. Olsen said.

"This trimaran should, for us, be the solution for many years to come and could very well set the standard for a new generation of large fast ferries. We believe our customers deserve the best".

During sea trials with operating ride control "Benchijigua Express" achieved a speed of 40.4 knots whilst carrying deadweight of 500 tonnes. 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 rated to 8,200kW which will be upgraded to 9,100kW during the first quarter of 2006. Those 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 manoeuvring characteristics equivalent or better than Fred. Olsen S.A.'s existing vessels," said Mr. James Bennett, Austal's Technical Manager.

"This has been achieved by fitting two Ulstein Aquamaster UL601 azimuthing bow thrusters supplied by Rolls-Royce. The ability to synchronise the thruster and waterjet control systems will give the vessel's Captain excellent control to ensure fast, efficient and safe operation in port. Once in open water the electrically driven thrusters are retracted into the hull to reduce drag and thus maximise the vessel’s speed and efficiency," he explained.

With electrical power provided by the vessel's diesel generators the bow thrusters can be integrated into the harbour 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 centre hull. The system consists of a single T-foil forward, two anti-roll fin stabilisers 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.

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. Nevertheless, the film is unique in that it 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%.

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 x 30 metre vessel and the potential for this relatively minor servicing problem to interrupt operations.

To this end a transportable cofferdam or caisson matching the unique shape of the centre 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 customised mounting points on the ferry it has proven to be a straightforward and successful solution to the original concern and another example of Austal's reputation of working with customers to creatively overcome problems to maximise operability and serviceability.

"While the Auto Express 127 trimaran "Benchijigua Express" set 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", said John Rothwell.

A team led by the US military supply company General Dynamics and including 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 metre 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 metres in length. One of these, the 101 metre "WestPac Express", has already proved highly successful in carrying out Theatre Support type duties for the US Marine Corps in the Western Pacific region.

Two further 105 metre catamarans are currently under construction at Austal's Mobile, USA shipbuilding facility.

PRINCIPAL PARTICULARS
Length overall: 126.7 metres
Length waterline: 114.8 metres
Beam moulded: 30.4 metres
Hull depth moulded: 8.2 metres
Hull draft (maximum): 4.0 metres
Deadweight (maximum): 1000 tonnes
Crew: 35
Passengers: 1350
Vehicles: 341 cars or
450 truck lanes metres 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 metres
Speed: 40.4 knots, 500 dwt, 32.8 MW

Tankage
Fuel: 145,000 litres
Fresh water: 7000 litres
Black & grey water: 7000 litres
Lube Oil: 2 x 600 litres
Hydraulic Oil: 2 x 600 litres
Sludge: 1000 litres

Propulsion
Main engines: 4 x MTU 20V 8000; 8,200kW at 1150rpm 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.

Survey Classification Germanischer Lloyd 100A5, HSC-B OC3 High Speed Passenger/Ro-Ro Type MC, AUT.

Ends.

For further information contact:
Austal
Public Relations
Tel: +61 8 9410 1111, Fax: +61 8 9410 2564
Email: pubrel@austal.com
Web: www.austal.com

Fred. Olsen S.A.
Tel: +34 922 628 221, Fax: +34 922 628 231
Email: lineas@fredolsen.es
Web: www.fredolsen.es