"Lloyd Sumpter" ) writes:

Anyway, I need some anecdotal feedback: First, a 16ft boat has a
theoretical hull speed of about 5.5 knots. HOWEVER, I've seen many boats
(such as my 12ft alum) that exceeds hull speed without truly planing
(semi-plane?) Does anyone have some performance numbers for 14-16ft
flat-bottomed skiff as to how fast they go before planing? I'm looking at
maybe 6-10hp engine.

Second, I'm unfamiliar with how a flat-bottom hull performs in waves -
are they seaworthy?

Thanks for any comments, stories, etc!

Lloyd Sumpter

If you want a planing boat following might be of use ....
If you don't want the boat to plane it might still be of use ...
If you don't want a planing boat then it should be long and narrow for good
fuel efficiency.

TF Jones writes that a boat should plane with 1 hp for every 40 lb
displacement. That should give you some idea of now big an engine
you'd need.

Flat bottom skiffs and garveys plane good. The back end of the
boat has to be broad and flat. Sorry, I don't know how much flat
bottom you'd need to plane a given displacement.

Planing boats are not good in rough water. You need smooth water
to plane in. You can increase "seaworthiness" by giving the boat
high sides and higher bow with the sides raked to keep spray from
coming on board.

Flat bottom planing boats slap the waves. That can be pretty annoying for
some people. That's why "ocean" skiffs have "V" bows giving 'way
to flat bottoms aft. The "V" cuts the waves instead of slapping
them. There are lots of old plans for these plywood planing skiffs.

Any planing power boat needs a good strong bottom to take the pounding.

Feel free to copy and use the Skiff program under Boats on my website to
try different dimensions. Its not for planing hulls because it assumes the
rise in the bottom aft. You can use it for a dory by making the transom
very small, or anything you can imagine in between a dory and a skiff,
like a drift boat.

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