Crew skill makes all the difference

In one-design boat racing, each boat is identical in shape, weight and power. Not only that, but each boat also has the same propulsion unit and drive. While it might prove difficult to tell who’s who, such restrictions mean that the race is a test of skill in which only the crew, not the design of the boat, makes the difference.

The boats themselves are only available from authorised constructors. And strict scrutineering of entrants, electronic engine control and electronic tagging built into the hull moulding alI serve to ensure absolute equality of equipment at the starting line.

One powerful new boat designed for such racing is the V-Class boat developed by Ocke Mannerfelt. The design itself follows his development of the remarkable B-28 ‘batboat’ (See Design Engineering, March 1995).

The hull of the boat is shaped so it rides on air. A double-stepped bottom reduces wetted surface area and lubricates the contact between boat and water. Above the water line, the aerodynamic contour reduces drag from the wind. A fin at the rear stabilises the boat against cross-winds. Removable wingtips on the hull sides create stability and lift to prevent the boat from flipping over and give a softer, more stable ride.

Each boat is designed to protect the crew, offering a combination of a self-righting airbag, emergency air supply, snap-off steering wheel and an advanced protection system. Drivers sit side-by-side in a fully enclosed safety capsule cockpit, featuring gull-wing doors that are fully watertight but can be opened from both inside and out. It only takes a minute to take off the two gullwing doors, converting the boat into a recreational cruiser.

With traditional powerboats, there is always the risk of crew being trapped in the upturned hull in the event of a capsize. Mandatory on all B24 raceboats is an automatic self-righting airbag system, which can be deployed by either the crew or external safety team. First, the aft part of the boat is lifted to get the crew’s heads above the water. Then the boat flips back on its keel, enabling cockpit doors to be opened. Scuba-type air supply canisters provide an emergency breathing supply.

Being a one-design class means that every B24 power unit has to be the same. The power unit used on this design is a Volvo Penta 5.7GSi petrol inboard with Duoprop drive. It has electronic, throttle body fuel injection and ECM engine management systems. What’s more, the B24 Concept sports fully submerged propellers to eliminate the risk of ‘propride’ as well as sudden loss of propulsion power.

Ocke Mannerfelt Design Tel +46 8 756 0360