How Fast do you think a 1981 15ft Boston Whaler Sport w/ a 70hp motor could go? (calm water, no wind)?

We just bought our neighbors but it doesnt have a speedometer.How Fast do you think a 1981 15ft Boston Whaler Sport w/ a 70hp motor could go? (calm water, no wind)?
depending on the load I would say 40 mph +/-
I will bet it will go about 40 to 45 mph.. My brother had a 16 foot bass boat with a 150 hp motor and it barely went over 60 mph so..How Fast do you think a 1981 15ft Boston Whaler Sport w/ a 70hp motor could go? (calm water, no wind)?
I would say about 40-43 mph. I have a 14 ft boat with a 25hp motor and it will go about 25-27 mph. Get it going wide open and get someone in another boat to ride beside you and tell you how fast you are going.
38 MPHHow Fast do you think a 1981 15ft Boston Whaler Sport w/ a 70hp motor could go? (calm water, no wind)?
That's a lot of motor on a 15 ft boat, evan as heavy as a Whaler is built you should see 35 mph pretty realistically, perhpas more, depending on your prop and what elevation you are running at. Most gps units can tell you your speed.
Theses speeds sound good for a 70hp. If you want blow your buddy* away, wax the hull with hard stuff that has Carnauda in it. Tune-up the engine, get an SST prop in the right pitch, check your tilt pin, you need the bow up but not to high.

AV GAS (aviation fuel 100-110 octane a few drops of extra oil). Remember I will not be held accountable for any of these modifications.



P.S Put a TACH in it. Top end who knows, let's find out.



37-40+ mph maybe. Use a GPS.
I was also thinking 40 mph. Fast enough for a 15 footer, it'll feel a lot faster. Have fun, be safe, wear your PFD!
240mph AT least, that thing sounds like a beast
Propped %26amp; trimmed correctly you should be able to get 44-48mph with the 70. Don't waste your time using race fuel, it will not benefit the performance, it will actually detract from it since higher octane=slower burn. Race fuel benefits a modified engine and the slower burn helps prevent pre-ignition / detonation which occur when compression is raised %26amp;/or timing advanced.



Have fun!