Born on Fair Isle
For the inhabitants of Fair Isle, a small island in the Shetlands, the Ghost Ship was a major attraction before it even took to water. As a community they had enjoyed ringside seats for its development since it was one of their own, boat builder Ian Best, who was charged with its construction. Ian had built similar boats before, but not in the short time demanded by the team (nine weeks). Building the vessel from scratch and largely by eye, Ian was able to complete his impressive task in the short timeframe.
Enter the engineers
With the boat constructed it was time to move to the University of Southampton for an intensive two months fitting. Supervised by Professor Grant Hearn and Professor Phillip Wilson and supported by University’s National Oceanography Centre, Southampton (NOCS) project manager Dr David Labbe was tasked with developing engineering solutions for the boat.
David explains that the first problem was how to match the propulsion method (sail structure and rig) with the particular shape of the boat. ‘The major consideration was balance,’ he says.
David was happy to discover that the shape of the sixareen had an equilibrium which simplified the process of selecting a rig. The sails proved a little more difficult. ‘We wanted them to operate autonomously, so this meant a system which could unfold and retract the sails and also perform tasks such as tacking at the touch of a button,’ he says.
Ghost Ship required both a main sail and a jib sail. To avoid ropes becoming tangled in fixtures on the boat’s deck it was decided that the jib sail, which is fixed to the bow, should be smaller than conventional sails and self-tacking to aid automation. A self-tacking jib usually relies on a rail system for operation. The rail forms an arc to the bow of the boat and the sail is fixed onto this and follows the rail on gliding ‘cars’. Ghost Ship would have no people on board, so a key priority was the control system.
The hydraulics presented a challenge. First there was the requirement to refresh the system at regular intervals by recharging the pressure inside the main hydraulic chamber while at sea. Then there was the need to ensure the system functioned during critical situations, such as the movement of the jib sail. ‘When you move the jib sail you pull on one rope and let go with the other,’ says David. ‘We had to construct the system so that the two sides were synchronised to avoid unnecessary stress.’
The next obstacle presented by the hydraulics was their lack of refinement. ‘A hydraulic system is either on or off — there’s no in between,’ says David. ‘This meant that if a rope was caught or a block jammed the system could rip something off the boat.’ The solution was simple: ‘We focussed on making sure there was limited resistance in the pulleys, winches, blocks ropes and glide cars,’ he adds. ‘I visited Harken inc., a world-leading manufacturer of yachting pulleys and winches, to discuss the use of their components on Ghost Ship.’