Austal reveals the advanced trimaran technology behind Fred Olsen SA’s new fast ferries
Fred Olsen’s next-generation trimarans are designed to boost seakeeping, passenger comfort and efficiency.
Bajamar Express was rolled out onto the hardstand at Austal Australia’s Henderson shipyard in Western Australia in December, in preparation for final fit out before launch in February 2020. The vessel is due to be delivered in Q2 2020.
Its sister ship Bañaderos Express is being built by Austal’s yard in the Philippines. Austal was awarded the contract for the two 118-m trimarans, worth over A$190M (US$131M), in October 2017 and began constructing the first vessel in September 2018.
This order comes on the back of Fred Olsen’s Benchijigua Express trimaran, delivered by Austal in 2005.
Capable of transporting more than 1,100 passengers and 276 cars at speeds of up to 38 knots, the new ferries feature Austal’s latest, optimised trimaran hull form and will be fitted with Austal’s motion control technology that delivers a smoother ride and an enhanced onboard experience for both customers and crew.
Austal technical manager sales James Bennett tells Passenger Ship Technology that the main considerations in developing the two 118-m trimarans are passenger comfort and reduced fuel consumption. He adds “The route the vessels will operate in the Canary Islands faces intense competition from local airlines. Being able to offer a high-speed vessel with greater comfort and improved sea keeping over conventional high-speed vessels is essential in the battle for passenger patronage.”
The decision to use a trimaran model over a conventional catamaran is based on Fred Olsen’s experience operating Benchijigua Express since 2005. “In that time the vessel has consistently demonstrated exceptional sea keeping when compared to other types of high-speed vessels. Compared to a catamaran, the trimaran hull form gives passengers and crew a more comfortable experience due to the lower vertical and transverse accelerations,” says Mr Bennett.
He expands upon the benefits of using a trimaran. “The primary answer is vessel motion. A catamaran, due to its two widely spaced hulls, is a very stable platform; this geometry inherently results in a fast roll period of about four-six seconds. The trimaran, with its narrow centre hull and low-volume amahs has a roll period over twice that of a similar catamaran. The longer roll period translates into a lower transverse acceleration. This characteristic, in combination with the long slender centre hull imparts a soft ride in bow quarter and head seas. Collectively, these features and characteristics create an environment where the passengers experience much lower accelerations and therefore a more comfortable ride.”
The ferry features Austal’s latest, optimised hull form. Mr Bennett says Austal’s latest generation trimaran hull form has been developed using advanced computer modelling and robust tank testing, to offer the “best seakeeping and low resistance”.
He adds “The low hull resistance means the new vessels will have a lower fuel consumption per passenger, compared to previous generation vessels.”
Optimising the vessel’s hull shape, reducing drag and improving efficiency has led to reduced fuel consumption. The new vessel also uses the latest generation silicon antifouling which contains no biocide.
Explaining the environmental benefits, Mr Bennett adds “Silicon-based antifouling offers year-round performance compared to conventional antifouling which tend to lose their characteristics as the operating year progresses. The trimaran hull form also generates lower levels of wave wash compared to other high-speed vessels, meaning the potential to damage fragile coastlines on the vessel’s route is greatly reduced.”
Motion control and smart ship data
Austal’s motion control technology, fitted to the new trimarans, consists of a large T-foil mounted on the centre hull near the bow of the vessel moderating pitching motion. On the aft end of each amah there is a pivoting foil that controls roll motions. Mr Bennett expands “The motion control system operates these devices in a co-ordinated manner to reduce the vessel’s pitch, heave and rolling motions. The design and engineering behind each of these devices has been developed over many years with a particular focus on easing maintenance and minimising the requirement to drydock the vessel for routine maintenance.”
There are several innovations on the vessel, particularly within the structural design, that have optimised the vessels’ lightship weight. Austal has been working closely with Fred Olsen to develop MARINELINK-Smart. MARINELINK-Smart is being designed to give the operator smart ship data gathering capabilities with the aim to help reduce operational costs via fuel savings.
Mr Bennett says “MARINE LINK-Smart includes intelligent learning modules monitoring and controlling vessel trim, fuel consumption, speed and engine rpm, and condition monitoring of ships’ equipment and components.”
The two ferries will be powered by four MTU 20-cylinder 8000 M71L engines and by Kamewa waterjets from Rolls-Royce.
Mr Bennett says “The propulsion configuration has been developed to ensure the vessel can operate safely in all sea conditions designed for, with excellent redundancy. Each of the four main engines drives its own waterjet and is independent from the other engines. This means a failure in one drive line will not impact the remaining three engines or waterjets. The vessel is designed to safely operate on three engines if required. The vessel is also fitted with two large bow thrusters to help with in-port manoeuvring. The Canary Islands are well known for the daily strong northeast trade winds, so excellent manoeuvring is essential.”
Benchijigua Express is also powered by MTU Series 8000 engines.
Fred Olsen technical manager Ivan Fernandez Martinez previously said, upon the announcement the vessels will be powered by MTU, “Benchijigua Express is a prestigious vessel in the world of fast ferries. It ticks all the boxes in terms of our high demands for power, speed and passenger satisfaction. On the back of this positive experience we have decided to install MTU engines in our new trimarans as well. These engines will be in service around-the-clock, and we need the best possible efficiency and fuel consumption coupled with low levels of downtime. We know MTU can deliver on this. Since being launched into service back in 2005, Benchijigua Express has not had a single passage cancelled by engine issues.”
Snapshot CV: James Bennett (Austal)
James Bennett is technical manager (Commercial) at Austal, based at the Australian shipyard at Henderson, Western Australia. As one of Austal’s earliest recruits and most experienced naval architect, he has contributed to the company’s success since 1989 and celebrated 30 years’ service in 2019. During this time, Mr Bennett has held various roles covering design, project management and sales and marketing. After qualifying with a higher national diploma in naval architecture from the Southampton College of Technology, UK, Mr Bennett worked at companies including Allday Aluminium in the UK, Seaconstruct in Singapore and Precision Marine in Western Australia, before joining Austal in 1988. Mr Bennett has been heavily involved in Austal’s research programme investigating new ferry platforms that combine the benefits of lightweight aluminium construction with LNG.