VESSEL REVIEW | MCS SWATH 3 – UK's Maritime Craft Services welcomes first crewboat in new series

Finnish shipbuilder Tyovene has handed over a new crewboat to UK operator Maritime Craft Services (MCS).

MCS SWATH 3 boasts a small waterplane area twin hull (SWATH) design that minimises motion in rough seas. Tyovene said that, by reducing vertical acceleration, the vessel ensures that technicians and crew arrive on-site rested, secure, and ready to work regardless of weather conditions.

The crewboat has an LOA of 29.6 metres (97.1 feet), a beam of 11.2 metres (36.7 feet), a draught of only 2.4 metres (7.9 feet), a displacement of 140 tonnes, a crew complement of six, and suspension seating for up to 24 technicians in a heated and air-conditioned saloon.

The builder added that the design is a result of close cooperation with UK-based naval architecture firm Ad Hoc Marine Designs, based on the experiences gained by MCS in operating two vessels that also utilise the SWATH design. The vessel has also been designed to satisfy the HS-OSC Code and new ballast water management rules under IMO Resolution MEPC.174(58).

Feedback from crews who have been operating these units for years helped optimise the design to ensure better workflow, easier maintenance, and thus more economic operability, according to Tyovene.

"MCS bought its first crewboats dedicated to the offshore wind industry in 2011, and by 2014 had a fleet of 10 vessels," Menno Kuyt, MCS Managing Director, told Baird Maritime. "These were standard designed catamarans that could only transfer personnel in 1.5-metre significant wave heights, and MCS believed there must be better hull forms that would meet the demands of clients that had windfarms further and further offshore.

"This is when we learned about SWATH vessels and how they do not follow the contours of the waves like conventional catamarans, which gives a very smooth rise for all on board."

The SWATH design reduces sensitivity to waves, ensuring smoother transits, safer transfers and improved stability. Advanced navigation, redundancy systems, and optimised boarding arrangements meanwhile help maximise operational security.

"The brief to John Kecsmar of Ad Hoc Marine Designs was for a high-performing SWATH vessel, as this type of hull form has the best sea-keeping capabilities," said Kuyt. "Passenger comfort with high transit/transfer ability were key factors, and our first Ad Hoc SWATH was delivered in 2016."

"From the in-service experience and feedback from MCS, this latest design incorporates a modified bow shape," added Ad Hoc Marine Designs' John Kecsmar.

"When on the tower, reducing the amount of vertical heave is important. Firstly the zero-heave mode of the motion control system already reduces the vertical displacement by over 70 per cent, but now with the modified hull shape, it provides greater damping in heave and pitch that then provides an even safer platform for the captain as they approach the towers at slow manoeuvring speeds."

Once on the tower, the boat "sticks like glue," according to Kecsmar.

As a scaled-up version of earlier crewboat designs, the new variant increases the maximum significant wave height limitation from 2.5 to three metres. Kecsmar said the smaller MCS SWATH 1 and MCS SWATH 2 have encountered 3.5-metre wave heights without issues, and so MCS SWATH 3 extends the upper limit even further to expand the window of operations.

Hybrid propulsion for increased reliability

The vessel is powered by two MAN D2862LE48B 1,066kW (1,430hp) main engines that comply with IMO Tier III and EU Stage V requirements. Each engine drives a Hundested controllable-pitch propeller (CPP) via a ZF 3050A gearbox to deliver a top speed of 23 knots and a cruising speed of 21 knots. The main engines can run on either MGO or HVO.

"MCS opted for CPP propulsion connected to joystick control," said Kuyt. "In addition, four stabiliser fins and two powerful bow thrusters are fitted. The CPPs give maximum thrust whilst pushing against the towers as well as fuel savings whilst in transit."

A PTI is installed on each drivetrain, allowing for hybrid operation. Also, because the vessel is capable of maintaining high service availability, instances of downtime are reduced.

Power for the onboard systems is supplied by two Kohler 35EFKOZD 35kW generators.

"The fuel consumption at slow and loitering speed is more than 50 per cent less than that of a conventional catamaran owing to its narrow beam," Kecsmar told Baird Maritime. "A catamaran’s wider beam creates an increase in residuary resistance that is not exceeded until operating at high Froude numbers."

The design’s improved seakeeping and noise-reduction features result in greater comfort for occupants during long transits to and from offshore platforms.

The deck equipment includes a Guerra M65 crane with a lifting capacity of 765 kg. The forward deck itself has 95 square metres (1,000 square feet) of clear deck space for the transport of assorted payloads totalling 12 tonnes.

Fixing points are also available for securing two 10-foot ISO containers to the deck.

Amenities and full electronics suite

The electronics suite includes a Furuno package with satellite and gyroscopic compasses, a GPS, radars, an ECDIS, an AIS, an echosounder, and a navtex. The other electronics are a Navitron autopilot and a Jotron TR30 handheld VHF radio.

The other onboard facilities consist of a pantry, a shower, and toilets. Also inside the main saloon are work tables and 230V socket outlets. The occupants will have access to wifi connectivity provided by Starlink.

MCS SWATH 3 will be deployed in the North Sea, where she will support ongoing efforts to expand renewable energy infrastructure. Construction of the crewboat was done in compliance with Lloyds, MCA Category I and IMO HSC requirements.

Another two crewboats from the same series will be handed over to MCS.

"We truly believe our Kecsmar-designed SWATH vessels are the highest performing crewboats in the industry," Kuyt told Baird Maritime. "We have had zero incidences of passenger seasickness on board and the higher transfer limits mean we can work offshore for up to 90 days longer compared to conventional crewboats.

"In November 2025, MCS SWATH 3 did around 450 push-ons, which is well above industry standard levels for the time of year."