reducing drag on a tri-hull boston whaler

beermunk

Petty Officer 2nd Class
Joined
Jun 20, 2004
Messages
146
i might be longing for something i'll never see, but the motor i'm running right now, a johnson 35hp, we used to be able to tube and ski behind when it was attached to v-hull boat.<br /><br />now i have it on my 13' boston whaler, and it would be fun if we could still pull a tube behind it, but the drag from the tri-hull gives it just to much to push forward to pull a tuber.<br /><br />i was wondering if anybody knows anything that could be done, maybe using a certain wax on the outside? anything would be helpful.
 

Jdeagro

iboats.com Partner
Joined
Jul 30, 2003
Messages
1,682
Re: reducing drag on a tri-hull boston whaler

WE have rigged many Whalers in this size with Smart Tabs to help them plane and increase top end. I am not sure by your message exactly what you are experiencing when you talk about forward push. If you wish call me at 800-233-0194.<br /><br />John
 

ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: reducing drag on a tri-hull boston whaler

Don't know about improving the surface of the boat hull but you could most definately get some better tubing puller performance by having an optional prop of decreased pitch.Do you happen to know what prop you are currently running? Do you know what the engines wot rpms are as set up.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: reducing drag on a tri-hull boston whaler

I spent an awful lot of time behind a 13-foot Whaler with a 35hp and it had no trouble pulling us out of the water on everything from skis, to knee boards, to tubes, etc. I suspect you've got the wrong prop for the new set-up... You may want to drop down a couple inches in pitch and see if that makes a difference.<br /> Also, does the motor run fine otherwise? Compression is good and motor is generally healthy?<br />- Scott
 

beermunk

Petty Officer 2nd Class
Joined
Jun 20, 2004
Messages
146
Re: reducing drag on a tri-hull boston whaler

well, if you read in the Johnson/Evenrude forum, you'll see that i'm having some slight problems with it, but before this, i couldn't pull a 180lb man out of the water with just me and a spotter in the boat.<br /><br />i did change the prop to the spare... i should put the old one back on and see.
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: reducing drag on a tri-hull boston whaler

The answer lies in the motor - not the boat.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: reducing drag on a tri-hull boston whaler

Agree with SoLittle. <br /><br />A 13 with 35 working hp and the right prop will do what you want to do.<br /><br />Could be the prop, but my guess is that your engine is way down on power.
 

Oldsaltydog

Petty Officer 1st Class
Joined
Jan 27, 2004
Messages
322
Re: reducing drag on a tri-hull boston whaler

No disagreement with the previous replies, but as far as waxing the hull in concerned, it REDUCES boat speed. Instead, a light sanding with a very fine sandpaper will slightly increase your speed (an old sailboat racers' trick) and so does a Teflon polish available at West Marine, etc.
 

HEDJUG

Cadet
Joined
Apr 26, 2004
Messages
18
Re: reducing drag on a tri-hull boston whaler

Do you have the trim pin set to far up or down?
 
D

DJ

Guest
Re: reducing drag on a tri-hull boston whaler

Where is the engine cavitation plate in reference to the bottom?
 

beermunk

Petty Officer 2nd Class
Joined
Jun 20, 2004
Messages
146
Re: reducing drag on a tri-hull boston whaler

in regards to the trim pin, what's optimal? should the lower unit be parrallel to the stern, or should it be out/in more?<br /><br />what is the engine cavitation plate?<br /><br />sorry, i'm not a full time sailor yet... :)
 
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