FBM hopes to cut a SWATH through the opposition

There have been a number of high speed SWATH (Small Waterplane Area Twin Hull) designs in the past but now FBM Babcock Marine has unveiled what it describes as the FSPV ? a revolutionary new high speed passenger ferry which promises to deliver pioneering rough condition seakeeping capability, coupled with speeds of up to 40 knots.

FBM claims the vessel, which is the result of a three-year test programme, is the first high speed ferry that successfully incorporates the SWATH form with waterjets, permitting speeds of up to 40 knots to be maintained in sea conditions beyond a significant wave height of 3m (relating to maximum wave heights beyond 5m). FBM has had previous experience in designing this type of vessel and already has a number of SWATHs in operation.

The first of these was the passenger ferry Patria, which has been in service since 1989. The second design is a passenger-transfer vessel for the UK naval fleet. A stable platform and good directional control were required by the MoD for passenger transfer in open sea conditions to and from warships and auxiliaries in the fleet.

In this case each of the aluminium alloy vessels is fitted with twin diesels driving conventional propellers to give a service speed in excess of 11 knot in Sea State 3. Accommodation is provided for up to 75 passengers and the transfer operation, which requires teams of up to 30 persons to transfer to or from the craft within a few minutes, is achieved by means of hydraulically adjusted telescopic gangways fitted at the upper deck at the aft end of the craft. The outboard end of the gangway in use is held against the receiving ship?s side with any movement corrected by sensors linked to the hydraulic system.

John Warbey, managing director of FBM Babcock Marine, says: “This vessel is the answer for fast ferry operators who have problems maintaining their service schedules due to weather conditions, or have exposed routes where reliable high speed services have previously been unfeasible. A development from FBM Babcock Marine?s proven SWATH technology, with three previous slower vessels in service, the FSPV will provide reliability and continuity of service in high seas with passenger comfort being far superior to that offered by conventional multihulls or hydrofoils.”

The FSPV features large deck areas enabling flexible seating layouts for typically 400 passengers, together with facilities for refreshments and duty free goods.

The SWATH form is acknowledged as providing the ride quality of a far larger vessel, whilst able to sustain its operating speed in rough seas. A SWATH vessel resembles a catamaran but with two submarine-like lower hulls submerged below the water surface and connected to the bridging raft by relatively thin vertical struts. The submerged hull profile and the high raft clearance permit the SWATH to smoothly ride over rough surface waves.

Christopher Atwell, FBM?s marketing manager, said that the vessel would cost more to build as the structure was more complicated than a conventional fast ferry design and would cost more to operate. However, he was confident that owners would be willing to pay the additional costs in return for a vessel that would offer improved seakeeping performance.

The FSPV has been developed with three engine choices dependant on the operator?s speed requirements. These include straight diesel, gas turbine or a combination of both. Access to the engines, which have long shaft lines, is via watertight hatches in the top deck, which says Atwell, allows for rapid direct entry for engine removal and easy maintenance. n