c.1960 13-footer with Johnson 40-HP

Optimizing the performance of Boston Whaler boats
Albert Jr.
Posts: 53
Joined: Wed Oct 28, 2015 4:26 pm

c.1960 13-footer with Johnson 40-HP

Postby Albert Jr. » Mon Apr 24, 2017 10:36 pm

My latest project (1970 SPORT 13) has been a complete success. The Tohatsu 40 we mounted is performing well, and, with this engine, we have managed to get a perfect weight distribution.

Now the owner of this new boat is very happy and he'd like to continue with another SPORT 13 from the 1960's. Only this time I am thinking about installing a 1998 to 2005 Johnson 40-HP outboard--he loves the Evinrude brand. The Johnson being heavier and only available in long shaft models, I am not sure if it will perform as well. I've ridden a 1980 SPORT 13 with a Yamaha F25 long-shaft, and the ride was just horrible. I get the models 1970 and 1980 are different, but it's the weight in my opinion that really comes into play here.

Does anyone on here have a video of their similar spec'd boat running?

Can anyone put me at ease with their experience?

Thank you.

Albert Jr.
Posts: 53
Joined: Wed Oct 28, 2015 4:26 pm

Re: c.1960 13-footer with Johnson 40-HP

Postby Albert Jr. » Mon Apr 24, 2017 10:38 pm

Latest project.

Take a loooong look at that waterline :D
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dg22
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Re: c.1960 13-footer with Johnson 40-HP

Postby dg22 » Fri Apr 28, 2017 5:29 pm

This is how my 1967 13 footer sits with a 1973 Evinrude 50 HP -- around 180-lbs motor. The boat handles best with someone sitting up front. With me alone in the boat, the boat does porpoise at lower speeds.

Whaler at Launch Sm.jpg
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Here is another pic to give you an idea how the boat sits with two aboard.

Summer 2012 SM.jpg
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Albert Jr.
Posts: 53
Joined: Wed Oct 28, 2015 4:26 pm

Re: c.1960 13-footer with Johnson 40-HP

Postby Albert Jr. » Sat Apr 29, 2017 10:49 pm

dg22 wrote:This is how my 1967 13 footer sits with a 1973 Evinrude 50 HP -- around 180 pound motor. The boat handles best with someone sitting up front. With me alone in the boat, the boat does porpoise at lower speeds.

Whaler at Launch Sm.jpg

Here is another pic to give you an idea how the boat sits with two aboard.

Summer 2012 SM.jpg


Nice boat you have there sir :)
If the bow stays low atleast, then porpoising shouldn't be that big a problem for me.

Have you tried adding a hydrofoil?
The Tohatsu 40 I installed has one and the bow does not rise at all.

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dg22
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Re: c.1960 13-footer with Johnson 40-HP

Postby dg22 » Sun Apr 30, 2017 6:24 pm

Thank you. My boat is far from perfect but does look ok from 20 feet --I laugh aloud--. I've actually never considered a hydrofoil. If the hydrofoil keeps the bow low, I'm sure it would also help for pulling water skiers. Maybe I should consider a hydrofoil. Thanks, Dave

Albert Jr.
Posts: 53
Joined: Wed Oct 28, 2015 4:26 pm

Re: c.1960 13-footer with Johnson 40-HP

Postby Albert Jr. » Wed May 03, 2017 12:15 am

dg22 wrote:Thank you. My boat is far from perfect but does look ok from 20 feet --I laugh aloud--. I've actually never considered a hydrofoil. If the hydrofoil keeps the bow low, I'm sure it would also help for pulling water skiers. Maybe I should consider a hydrofoil. Thanks, Dave


Great, keep me posted

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dg22
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Re: c.1960 13-footer with Johnson 40-HP

Postby dg22 » Tue Jun 27, 2017 10:50 pm

I installed the hydrofoil and it did help reduce the porpoising. I also like how it keeps the bow low when getting on plane. My top end speed seems to be about the same as i'm still around the same top end RPM's. My motor, by the way, is mounted a little higher up on the transom by 1 inch so I think that helps reduce the drag of the hydrofoil. With the hydrofoil, the boat overall feels more stable particularly with me alone driving the boat -- it definitely feels safer. It was well worth the $70 I spent on the hydrofoil.