proto-4 was to be, as near as possible, a full pre-production prototype. Most of the boat and transport issues had been sorted with proto-3 and most of proto-4’s development work related to ‘production’ – to be able to make each boat with the minimum of hassle and the maximum of reliability. I decided that, mostly down to the small size of the workshop, we would make the ROCAT in batches of 3.

The first major job was to install electric programmable heating in the main moulds in order to post-cure the parts. This improves the part’s strength and increases its tolerance of high temperature – a dark hull sitting in the sun gets very hot and, without such treatment, it can melt!

Then there were jigs and foam moulds and more hull frames to be made.

The hull mould had developed some faults, so we took time out to refurbish it, and then take reference plugs from the refurbished mould to simplify the production of further moulds later.

The ROCAT’s finish was the subject of much debate. Conventionally, a coloured gelcoat would be applied to the mould before the glass, and no post-finishing would be required. But there were disadvantages in the ROCAT’s case concerning resin compatibility, moulding flaws repair and limited colours. Also, committing to particular colours at the moulding stage made the production workflow less flexible. So we sprayed epoxy primer into the mould and then used very tough two-pack automotive paints for the finish – and it looked gorgeous!

Once completed, proto-4 was a real joy to use because everything worked just as it should, from loading it on to the car, to assembling it on the harbour slipway, to rowing out across the bay whatever the conditions.