VESSEL REVIEW | Seacat Columbia – UK-built crewboat features innovative stabilising hull design

A new crewboat slated for UK operator Seacat Services was recently completed by Isle of Wight shipbuilder Diverse Marine.

Designed by local naval architecture firms BAR Technologies and Chartwell Marine, Seacat Columbia has a length of 30 metres, a beam of eight metres, a draught of 1.6 metres, and capacity for 24 passengers/technicians. Active foiling systems correct for pitch and roll even in significant wave heights of 2.5 metres while a narrow hull form combined with a SWATH-style outrigger helps minimise both vessel motions and fuel burn. BAR Technologies said that the vessel will be able to operate in more challenging conditions compared to current catamaran designs, which then means that offshore wind turbines may be serviced under a greater number of sea states.

The new crewboat was designed to address the issues of vessel efficiency – and therefore emissions reduction – and comfort in transfer, and subsequent effectiveness, of offshore wind engineers, which BAR Technologies claims are the two most pressing challenges of the offshore wind industry. Trips to offshore wind turbines can be aborted on account of technicians' fatigue, leading the designers to develop a craft that can safely perform crew transfers lest operators incur additional costs from these aborted trips.

The hull design and the active foiling systems help minimise vessel motion and fuel burn, leading to an average increase in stability across all sea states of up to 70 per cent and a reduction in total emissions of 30 per cent over a typical operational profile. The designer said these attributes make the crewboat one of the first low-emission vessels serving the UK's growing number of offshore wind farms. Specifically, the crewboat was designed to achieve greater fuel efficiency that can yield CO2 emissions reductions of as much as 1,200 tonnes per year.

BAR Technologies claims the combination of the incremental hull length, bow thrusters, and directional jets give this craft the equivalent manoeuvrability of a standard catamaran. The significantly improved seakeeping of the BAR crewboat ensures fewer abortive trips and a greater operating window, providing fewer delays as well as greater efficiency, while having a cost comparable to that of current catamarans.

Seacat Columbia is currently serving its first charter, a contract for crew transfer services in support of Equinor's Sheringham Shoal and Dudgeon offshore wind farms off the coast of Norfolk.

Three other crewboats from the same series will be delivered to Seacat following completion at Diverse Marine's facilities.