VESSEL REVIEW | Swedish high-performance interceptor features fully integrated propulsion and electronics

Swedish boatbuilder Marell has launched a new 15-metre patrol boat demonstrator craft designed as a reference model for a high-speed interceptor with speeds of up to 70 knots.

It was built based on a well-proven design from the former Marinteknik, but refined by Marell Boats, with longitudinal stiffening and sharp bow and longitudinal strakes to be able to run fast but also dry in higher sea states

A durable vessel designed for anti-piracy operations, border control, intelligence gathering, maritime security, and force protection missions, the boat provides cruising speeds of between 30 and 40 knots, and offers very good "grip" in the water, which in turn gives extremely high acceleration and safe high-speed turns.

With passenger comfort being a high priority for the builder, the strong aluminium hull, the composite superstructure and the shock absorbing seats are all designed to reduce impact from the sea, which could create substantial G-forces (up to 40G) when driving the vessel at speeds around 50 to 70 knots.

The hull has a sharp V bow with full body and longitudinal strakes to cut the breaking waves, reduce wave impact and keep the deck dry.

The superstructure has a high front deck and aft leaning front windows, to avoid larger waves to damage structure or jeopardise stability in heavy seas. The specially designed Daytona seats from Ullman Dynamics have twin shock absorbers creating a semi-active progressive shock mitigation system to provide high levels of comfort in extreme sea conditions.

The vessel is as standard equipped with a complete integrated propulsion system from Volvo Penta for reliability, redundancy and safety. The contra rotating propellers and the high torque diesel engines ensure maximum grip in high-speed turns, outstanding acceleration and manoeuvrability and very low fuel consumption.

Equipped with twin D6-440 DPI sterndrives, the boat has a top speed of 45 knots and includes Volvo Penta's "electronic vessel control" (EVC.2) and "glass cockpit" systems.

With new combustion engineering, lower friction and lower tolerances the Volvo Penta DPI has managed to reduce fuel and oil consumption even further. With the optimised drive leg, gear ratios and duo props, the average fuel consumption for the vessel is only 3.4 litres per nautical mile at 40 knots.

The new hydraulic clutches on the new DPI sterndrives give silent and smooth shifting. They also enable slipping at low engine speeds, resulting in greater manoeuvrability and higher comfort at low boat speeds. The hydraulic clutch, together with electro-hydraulic steering gives improved joystick steering, manoeuvring and docking functionality.

The propulsion package includes also a fully integrated interceptor system designed by Humphree, which is used for fine tuning of trim and heel, including an antiroll function in rough weather.

One of the vessels main features is the central ergonomic helm station together with a starboard navigation station and a port-side engineer/workstation. The vessel has a full glass cockpit design, which means a fully integrated control and navigation system able to configure for different needs with all alarms and engine information up front on all connected screens to the system.

In front of the navigator you have two 17" displays, one for radar and one for charts. The helmsman has a 24" display in a low front position, giving clear direct boat information without interfering with forward vision.

The navigator can mirror the navigation information from the 17" screen at starboard to the centre 24" screen, giving real time info all the time. The helmsman can fully focus on the high-speed interceptor and boarding mission with safe driving in all weather conditions.

This vessel is also equipped with MOB stations, one on each side on the aft deck platform, for precise rescue and docking operations. These joystick-docking stations each include a 12-inch navigation screen.

This new vessel, with its complete propulsion and control package, is designed for various high-speed security missions. The Volvo Penta EVC system includes all features needed for such operations, such as the possibility for system override, full black screen and remote helm. The latter will mean that the vessel can be unmanned and controlled remotely.