We have been working closely with Piriou developing and finalising the vessel designs ready for building to commence in June. The Scillonian IV design progression has seen the introduction of a Hull Vane®.

The Hull Vane® consists of a submerged fixed wing at the stern of the vessel. A wing placed in a flow generates two forces: a lift force and a (much smaller) drag force. The flow under the aft ship is not horizontal but angled upwards. When designed well, the force generated from the Hull Vane®, which is the sum of the lift and drag force, is angled forward.

This means that it has a vertical component (lifting the aft ship), as well as a net forward horizontal component (pushing the ship forwards). Model tests in waves have shown that the Hull Vane® significantly reduces ship motions such as pitching, heaving, rolling and yawing, and thereby reduces the added resistance from these motions by 10 to 30%.

Furthermore, when the ship is pitching, the Hull Vane® produces more forward thrust, an effect which is called the “pumping effect”, as it is similar to what surfers do on surfboards equipped with hydrofoils.

15 knots with Hull Vane®

15 knots without Hull Vane®