Re: How fast should it go?
I have a Starcraft 15 foot v-hull runabout (aluminum, relatively flat bottomed at the transom), spec sheet for that year says 440 lbs, with a 40 hp big twin motor (about 160 lbs), add in a six gal gas tank and a trolling motor and extra battery and me, you're at about 950 lbs, and it goes 30 or 31 flat out, cruises easily at 22. I would say 24 to 26 max for your setup, cruise at 19-20.
Boats that have ten or so lbs (just lbs of boat "dry weight") per hp (say a 1900 lb bass boat with 190 hp) are fast--like 64+ mph. boats with 20 pounds per hp (like a 1600 lb runabout with a 80 hp motor) tend to run something in the low 40's or high 30's top end. As speed goes up drag goes up, so you'll see tests where the 4-cyl 3 liter sterndrive version of a runabout goes 39 mph, and the 220 hp V6 version goes 43. Lotta money to pay for a marginal return.
Most every top end figure you see in boat tests for an aluminum fishing boat with a 40 or 50 hp motor tends to be something like 28 mph or a little more. Not that anyone would want to do that all day. Boats are like cars -- if you want to drive around all day at 90 mph, get a powerful car that'll go 140. Driving around all day at 90 in a little gas-saver car ain't no fun 't'all. That setup you've got is right down my alley -- easy on gas, enough speed to get around and buck a little current.
Starcraft67
