Re: Key West 19 cc
first, a boat speedometer is seldom accurate; you need a GPS or a another boat with one for that.
if it's one of the flat bottom hulls I'd think you'd be able to get up to 35-40 at top end, trimmed right. And of course the prop makes the difference.
To see if you are getting optimum performance you need to cross-reference your speed with your RPM's in 500 rpm steps up to "WOT" (Wide Open Throttle) in flat conditions and a light, but typical load. The condition of the bottom of the boat makes a difference, too.