Used work boats are extraordinarily cheap, usually $10k for a 40' boat that's 16' wide, and then another 10-15K for a used marine diesel engine. Compare that to a fiberglass pleasure yacht where you might pay $30k for a 30' boat and 50K for a 40' sailboat used, plus 8-12k for a marine diesel engine.

Same goes for trucks, you can buy a brand new F-150 crew cab for $35,000 with all the fixings, or you can buy a 5-ton truck military surplus that can tow ten pickup trucks for $8,000.