As this is quite a spacious boat I always intended to try to make it 'unsinkable' with foam filled spaces and also to aid stability by keeping water near the centre of the hull as far as possible. So I planned a central corridor the width of the battery along most of the hull to contain everything. The bulkheads of this corridor to be made of thin plastic sheet (0.5mm) to keep the aerosol foam under control.

This plan suffered a blow when the float test showed the battery needed to be further aft and sideways on to get the weight distribution near correct. So the corridor had to have a wider 'room' in it to contain the battery and that of course made it a more complex construction.