Of course if you have a decent sized (read that to mean big) sailboat with an inboard engine, then yep.
Or if you have a tender with a 30 hp outboard, then yep.
If you've got a sunfish and you will only ever have a sunfish, then you're fine
I am not familiar with how they rate diesel engines, do they do that in HP comparable to gasoline, and do the same rules apply? (a number of ocean going sailboats that could appear on Winni may have diesel powerplants)