From what he had in the workshops, I think they would be sea going wooden hulled yachts (no more than 50 foot), that they restore for customers. One yacht they are restoring was used in Dunkirk (even had bullet holes in the old wood that they removed!)
Just trying to get an idea of what’s evolved. There are quite a few boat yards around Truro, especially around the Falmouth area, so it could be another string to the bow!