Yep, XR18 hull. I sold the mould to a guy from Bognor Regis. Last time I spoketo him he had repaired the mould and was making a rib for himself. Looks like he made another too.
The are sensitive to weight in the stern therefore a 2 stoke 90 would be ideal rather than an overweight 4 stroke.
Ribnet is best viewed on a computer of some sort