[Fr. Frank]

For most boats under 20', the transom rub rail is the widest part of the boat. But since you round everything UP to the next higher full foot integer, it often makes little difference. A hull with a 7'4" transom gets the same calculable width as one with a 7'11" beam.

Also remember, the USCG max HP figures for boats longer than 20"0" are just recommendations, not regulations. The USCG nax capacity calculations for length are figured as LOA (length over all) and INCLUDE propulsion machinery, aka outdrives, outboards, transom-mounted rudders, et cetera. Permanently affixed additions are also included. Got an anchor pulpit? It gets calculated in. Got a swim platform? Add that. Got a bracket and outboard? Add them in, too. Add in anything permanently affixed to the hull.

My last Seafari was 19'8" hull, plus 11" anchor pulpit, plus 29" to tip of lower unit trimmed to neutral, for a total allowable calculable length of 23'1", which then gets rounded up to 24' for max capacity calculations.

As for max HP, there were at least a couple of Seafari 20's built with 260 hp sterndrives. I think the 20" transom also played a factor in SeaCraft's max OB hp recommendations.

Originally Posted by FishStretcher

So the reference I found notes that you use transom width. Not beam. Presuming that the stated beam is the widest part of the hull, and judging by the outline drawings, the transom is narrower.

The reference is here: http://files.dnr.state.mn.us/educati...atbuilders.pdf

I don't have a tape handy or a boat, for that matter.

I seem to recall 175hp being the limit- perhaps because of the transom stern being narrower than the beam.

I can only retrieve the seafari spec page, but it lists 175hp max. Perhaps this is why?