Putting trim tabs on dinghy

[MV Wanderlust]

Good Morning,

I'm hoping some of you can provide advice and/or share your experiences with putting self-leveling tabs on a small boat. Here's the scenario:

We have a 10' rigid dinghy. It resembles an inflatable RIB but it's entirely fiberglass, including the pontoons. It is a center console with a steering wheel and throttle/shift controlling a four stroke, 15 HP Mercury. The outboard already has a dolphin tail on it. With a full fuel tank, it weighs about 475 lbs.

With two of us sitting on the bench seat, the bow picks up quickly but it will only plow, even at full throttle. Once the bow comes up, if the passenger moves up to the bow, the dinghy pops up on plane nicely and the speed triples. At that point, the passenger can return to the regular seat and it will remain on plane.

There are several companies that manufacture self-leveling trim tabs. These are made by Bennett. We are wondering if installing a pair of these would allow the dinghy to get on plane without the passenger having to hop back and forth to the bow? Has anyone done this before?


Baby. Can't see the rear of the transom in this shot.


Close up of the starboard side of the transom (sanding down the bottom paint). The bracket on lower right would need to be removed but it isn't being used for anything, anyway.

Your thoughts are appreciated.

Thanks.

John

[Bleemus]

Just get a stabilizer fin. Problem solved.

https://www.amazon.com/s/?ie=UTF8&ke...29wacwjr_e_p19

[MV Wanderlust]

Originally Posted by Bleemus

Just get a stabilizer fin. Problem solved.

https://www.amazon.com/s/?ie=UTF8&ke...29wacwjr_e_p19

Thanks, Bleemus, but it already has a stabilizer fin installed and still won't get up on plane without help.

[Sailmonkey]

Does it have power trim?

Trim the prop all the way forward, then trim up once planing.....

If not, try moving the trim one hole forward.

[puffcard]

I have a set of tabs for a dinghy, never installed will sell for 1/2 price. PM if you want more info.

[MV Wanderlust]

Originally Posted by Sailmonkey

Does it have power trim?

Trim the prop all the way forward, then trim up once planing.....

If not, try moving the trim one hole forward.

Hi Sailmonkey. This Mercury doesn't have power trim and the trim is already adjusted to the most forward hole.

[Sailmonkey]

Originally Posted by JohnEasley

Hi Sailmonkey. This Mercury doesn't have power trim and the trim is already adjusted to the most forward hole.

Ah well, scratch that

[paulajayne]

Originally Posted by JohnEasley

Hi Sailmonkey. This Mercury doesn't have power trim and the trim is already adjusted to the most forward hole.

Move back one hole at a time and retest.

[kelbylinn]

I wonder if the manufacturer of the dinghy would have a solution for you? I have a rigid 10.5' Bullfrog with a 15HP 4 stroke Tohatsu on it, and it will get up on plane with 2 sitting on main rear bench. I don't have a center console though which I'm sure is extra weight. If you're having problems like that, others surely are too and the mfg may have encountered this problem before. Good luck!

[2geer]

We found a combination of both the Dole-Fin and the T-H Marine transom wedges worked well. I read about this recommendation on Walker Bay's website somewhere.

https://www.amazon.com/T-H-Degre-Pos...transom+wedges

The wedges install thin end down, fat end up. Gives the outboard about 5 extra degrees of negative trim.

Good Luck!

Dave & Lisa Geer
M/V Stout
kk42-087

[stewie]

Been there and this cured the problem.Put a couple of steps either side of the outboard to the end of the pontoons. Ply will do. This will lengthen the waterline length and stop the transom from digging in.

[HopCar]

I had a similar problem with a plywood Skiff I built. I installed a set of tabs similar to the Bennet you referenced. It worked very well. I'm now able to get on plane while sitting on the rear bench seat.

[MV Wanderlust]

Originally Posted by stewie

Been there and this cured the problem.Put a couple of steps either side of the outboard to the end of the pontoons. Ply will do. This will lengthen the waterline length and stop the transom from digging in.

Hmm... interesting idea, stewie. Have any photos of it?

[HopCar]

Originally Posted by JohnEasley

Hmm... interesting idea, stewie. Have any photos of it?

The trim tabs do the same thing that Stevie did. You need surface area further aft to lift the transom. Now that I think about it, the tabs I used were fixed. Not spring loaded. They use a turnbuckle to adjust the angle if you need to. Mine ended up flush with the bottom of the boat.

[MV Wanderlust]

Originally Posted by HopCar

The trim tabs do the same thing that Stevie did. You need surface area further aft to lift the transom. Now that I think about it, the tabs I used were fixed. Not spring loaded. They use a turnbuckle to adjust the angle if you need to. Mine ended up flush with the bottom of the boat.

But the concept is the same. Okay, good to know. Thanks.