Whaler Central - Boston Whaler Boat Information and Photos

Posted by speed_demon on 08/02/12 - 1:51 PM

I'm installing an 85hp Yamaha 2-stroke on my 1987 15ft Striper and I was hoping to get an estimate of what it might do with the right prop. I was able to get 35mph out of my 50hp Yamaha 4-stroke with about 650lbs of people and gear. I was running a a 14 pitch at 5500rpm so I think I could have got more like 38 with a light boat and maybe a 13 pitch prop. My 2-stroke weighs about the same. What do you think it would do with 85hp, unloaded with the right prop?

Posted by brooks89 on 08/03/12 - 10:28 AM

What's the max HP the boat is rated for? 85HP on 15' boat seems like a lot of horses.

Posted by Jeff on 08/03/12 - 10:34 AM

A few early 15's had a 75hp rating (1976 hulls only) but all of the rest are rated at 70hp. We had a 75 Mercury on our 1989 Super Sport and it was really too fast. The 15' hull has a tendency to chine walk at high speeds and if you do not know how to what to do when that happens things can get scary.

For high speed running the hull really needs a flat running pad at the stern. In this project Mick built a running pad on his 15 Custom and with a Yamaha 130hp V4 saw just over 64. With a 2.6 liter Yamaha 220hp V6 the boat saw 69-70 and it was under propped.

Edited by Jeff on 08/03/12 - 10:43 AM

Posted by Bake on 08/03/12 - 7:25 PM

Before seeing toms post I was thinking 45 to 50 mph. I have a 15 with a 70 Yamaha. My brother in law has a 15 with an 88 Johnson. Both run about the same top end. 42ish. I think he has more but may not be set up to get all he could. Although he gets there faster than I do he was quite surprised my 70 would keep up

Posted by dgoodhue on 08/04/12 - 7:00 PM

High 40's without a jackplate and optimal engine height/prop as Tom mentioned. Jackplates are worth 3-4 mph on a 15.