One of the original Buccaneer design concepts was the use of hydraulic drive. 

The engine is coupled directly to a pump which circulates the hydraulic fluid via a control valve assembly, to a hydraulic motor in the bilge skeg coupled directly through to the propeller on the other side.

The flexible hose connections enabled the diesel engine to be transversely mounted out of the way in the stern freeing up the cabin area which is the feature of the Buccaneer cruisers. The same system was used on most other Bounty cruisers.

The control valve gives forward, neutral and reverse control without the need for a mechanical gearbox. The method is simple, reliable, quiet and easy to maintain.

The photo below shows the pump (in red) on the end of the engine shaft and the flexible black hoses from it to the red control valve and fluid reservoir assembly in the bottom left hand corner.