Damen in the Netherlands has been building Multi Cat workboats for years – the latest evolution of the design is a workhorse specifically intended for the renewables industry
Damen recently delivered the first example of its renewables service vessel (RSV) 3315, a new design developed in close co-operation with Scottish company Delta Marine for work in the offshore wind industry. Delta Marine took delivery of its first Damen vessel 12 years ago, and the Shetland-based company now has four Damen Multi Cat vessels in its fleet as well as one it manages.
The first in the new series was named Voe Vanguard at Damen Shipyards Hardinxveld. A week later, Voe Vanguard was off to its first offshore windfarm, the Walney Extension project.
Jos van Woerkum, managing director of Damen Shipyards Hardinxveld, said the Dutch company has been working on the design of the vessel with Delta Marine since 2013. “Delta Marine gave us a sketch and outlined their requirements, and I think Damen has built exactly what they wanted,” he said. “I think the renewables service vessel has the potential to be a big success for Damen once it has proved itself in the market.”
The RSV 3315 design can undertake all duties normally expected of a Multi Cat but also has a spacious, unobstructed deck, class 2 dynamic positioning (DP2) and dedicated four-point mooring.
The Dutch ship designer and builder describes the evolved Multi Cat as a “serious workhorse” with powerful propulsion generating a bollard pull of 42 tonnes whilst remaining under 500 GT. Added to this is a standard outfit of cranes and winches. With the option of DP2, a four-point mooring system, two good size cranes and hydraulic shark jaws with guide pins, the vessel is designed to be able to undertake a wide range of duties. An AHT winch can be deployed over both stern and bow. Safety and visibility were key design guidelines along with the largest possible deck space, enabling the RSV 3315 to load equipment, carousels or remotely operated vehicles or be used as a walk-to-work vessel. The foredeck provides room for containers.
David McNaugthan, Delta Marine general manager, says the decision to invest in a vessel specifically tailored for renewables was taken around four years ago. “We knew at Damen we get a good project and good quality backup.”
“We were particularly interested in having DP2 capability. This vessel is suitable for offshore wind but also for tidal projects, where it can stay in position using DP in some pretty strong currents,” said the owner.
Delta Marine and Damen adapted the traditional Multi Cat design by moving the wheelhouse forward and leaving the aft deck open. Additionally, it was important to make sure the vessel was under the 500-tonne mark to keep costs down.
“The vessel is diesel-electric and has four azimuths with a large stern thruster. It is also very flexible, with a shallow draught of only 2.6 m. The two aft azimuths can swing up into the hull, and we can easily switch from DP1 to DP2 mode,” said Delta Marine.
In addition, Voe Vanguard has two powerful cranes, one of which has a capacity of 15 tonnes with an outreach of 20 m. “With these, we can carry and lift an awful lot for a wide variety of tasks.” The vessel has comfortable accommodation for 18 crew.
Delta Marine said the DP2 system is “very important for our clients” and “every single job is crying out for DP2”.
What other advantages does Voe Vanguard have? It also benefits from the same broad back deck associated with a Multi Cat, and it has a decent turn of speed, having a transit speed of 10 knots. It is also very flexible. With two switchboards for redundancy, it is possible to operate all four thrusters from a single engine if need be, and it is a genuine, go-anywhere unit, able to operate in shallow water when required.