VESSEL REVIEW | Fionn Mac Cumhaill – Fast aluminium crewboat for Irish and UK windfarm support

Irish Commercial Charter Boats (ICCB) of Malahide, County Dublin, has taken delivery of Fionn Mac Cumhaill, a 15-metre (49-foot) aluminium crewboat designed by Rockabill Marine Design (RMD) and built by Seabound Engineering at Greencastle, County Donegal. The newbuild is the operator’s principal craft for crew transfer to offshore wind and other nearshore projects in Irish and UK waters.

ICCB commissioned the design from RMD in February 2024. The 15-metre boat has a beam of four metres (13 feet), a draught of 0.6 metre (two feet), and a gross tonnage of 15.

The vessel was designed from the outset to satisfy two regulatory regimes. On the Irish side, it holds a Marine Survey Office (MSO) P5 passenger boat licence, which, under Department of Transport rules, covers boats carrying no more than 12 passengers for reward on domestic trips through smooth waters, partially smooth waters or at sea.

On the UK side, the design meets the Maritime and Coastguard Agency (MCA) Workboat Code Edition III, which has applied to new workboats since December 13, 2023. ICCB has referred to the vessel's MCA approval as Category II.

Designed from the outset to satisfy diverse vessel code requirements

ICCB said the vessel was delivered with an Irish P5 licence for 12 passengers and two crew. The dual approval allows the vessel to work across both markets. Irish east coast wind projects sit within a short passage of UK waters, and a crewboat able to work under both codes can move between contracts on either side of the Irish Sea without the need for re-certification.

RMD said that, after the late-November 2025 launch at Seabound, surveyors from both the MSO and the MCA witnessed a lightship survey and incline test.

"Every weight shift and every reading confirmed the design and work," the designer said, adding that the vessel was, "bang on weight target". Machinery commissioning and sea trials followed, and the vessel made its delivery passage to Malahide Marina in the first week of December.

Weight is important on this design because of the propulsion arrangement. The specification called for a pair of OXE 300 diesel outboard engines, giving a combined installed output of 600 hp (350 kW).

Proven diesel propulsion for heavy duty use

Diesel outboards on crewboats remain uncommon in Europe, where inboard diesels driving waterjets or conventional propellers are the norm for such vessels. The case for them rests on maintenance access, engine swap times, and fuel commonality with the offshore vessels the crewboat serves.

The design specification gives a maximum speed of 25 knots at full cargo load. Deck cargo capacity is listed at one tonne.

Tankage is roughly 1,000 litres (220 gallons) of fuel and the same volume of fresh water. Fuel capacity equates to about eight hours of running on both engines, which fits a day-boat operating pattern between a marina or harbour base and turbines or construction spreads off the east coast.

The wheelhouse is fitted with Simrad electronics and a SeaStar steering system with matching engine controls. Accommodation for the 12 passengers is supported by a head and wet room and a full galley, an arrangement intended for technicians spending long days on the water rather than short shuttle runs.