Given the abuse that they receive in service I would have thought a 50 hp Tohatsu would be ideal. Normally grossly overloaded with divers and kit, badly driven by the senior service, feck all maintenance unless it punctures, kept rolled up in there bags for years. Transported and abandoned all over the world by crab airways from tropics to the Falklands.
We always used them with single 40 hp mariners btw but a newish one has appeared in Haslar with twin 25/30s on her.
Ribnet is best viewed on a computer of some sort