Izar promotes pentamaran

The pentamaran design first patented by Nigel Gee & Associates (NGA) six years ago looks like it might eventually get built. The backing of Spanish shipbuilder Izar has given the vessel?s British designer Nigel Gee optimism that a contract can be won. Gee?s optimism is such that he expects an order within the next month.

“A lot of people are talking, but we believe the 175 [the pentamaran design] will be built and will work,” says Gee.

Izar has an exclusive licence to build the pentamaran in Europe. An initial five-year licence, which is extendable, was signed in September 2001. Izar and Gee are promoting the Spanish group?s San Fernando shipyard in Cadiz as the builder. The yard is Izar?s development centre for high-speed vessels.

The licence covers roros and ropaxes. There is also a sub-licence for large military ships for the US. The licence does not, though, cover containerships or small passenger craft.

The pentamaran is designed for low drag, which allows a combination of steel construction and speed (about 40 knots) utilising diesel machinery burning low-grade fuel, says Gee. It also offers a relatively high load carrying capacity compared to aluminium hulled vessels and good sea-keeping, he adds. “It?s not a stretched aluminium passenger ferry, which is the big difference,” he says.

Speaking at the 18th Fast Ferry Conference earlier this year, Izar?s Juan Antonio Moret said: “Simply scaling up existing aluminium conventional monohulls for this high speed, high deadweight role would produce designs for vessels that require very large powers and probably the use of gas turbine prime movers. The cost of such solutions would probably be unattractive to owners seeking to enter this market.”

The Izar pentamaran 175 fast ferry is developed for a wide range of potential routes in the Mediterranean and northern Europe. Alge?iras to Ceuta and Barcelona to Palma were looked at in particular. The design promoted has a full load standard deadweight of 900t, with the capacity to carry 1,000t. This translates as up to 1,200 passengers, up to 280 cars and up to 28 heavy trucks, depending on configuration.

Should an engine fail or if higher speeds are not required, the vessel is designed to operate on machinery that is available. The vessel?s design particulars have four 13,050kW medium-speed diesel engines installed. Moret said: “Speed when running with three engines is 37 knots in calm water at full load displacement, and with two engines 33 knots.”

In both cases, the waterjets are operating clear of their cavitation limits, he explained. The central waterjet is powered by two diesel engines running through a combined gearbox and, to allow the torque output of only one of these engines to run that waterjet, a two-speed arrangement is fitted to the output gears of the combining box, he said.

A fast turn around is required to enable the vessel to operate efficiently. Izar/NGA have therefore designed a number of garage deck arrangements. They favour stern loading and discharge. This, they believe, is particularly suited to the wide beam pentamaran because it allows trucks to be turned on the vehicle deck.