"fin" for dink's outboard

[MikeP]

We have an 11ft Avon RIB for our dink. It works well for us and mounts on the FB, raised/lowered with our davit. It has a 6 HP Tohatsu motor which I bought a couple of years ago. The motor has been excellent as far as operation is concerned but it is too small for the dink. I'm thinking of buying a 15 for it but before I do so thought I'd ask about something:

I have seen horizontal fins sold to be bolted on outboards that are supposed to make them perform better. Our dink/6HP motor will not plane under most conditions. SOmetimes, if the wind/waves are right, it will finally start to get up on plane but then will easily fall off. WOuld one of these fins help or are they just a marketing trick?

These things are what I'm referring to: http://www.savvyboater.com/c-19-hydrofoil-stabilizers.aspx

 

[rsmith]

We have an 11ft Avon RIB for our dink. It works well for us and mounts on the FB, raised/lowered with our davit. It has a 6 HP Tohatsu motor which I bought a couple of years ago. The motor has been excellent as far as operation is concerned but it is too small for the dink. I'm thinking of buying a 15 for it but before I do so thought I'd ask about something:

I have seen horizontal fins sold to be bolted on outboards that are supposed to make them perform better. Our dink/6HP motor will not plane under most conditions. SOmetimes, if the wind/waves are right, it will finally start to get up on plane but then will easily fall off. WOuld one of these fins help or are they just a marketing trick?

These things are what I'm referring to: http://www.savvyboater.com/c-19-hydrofoil-stabilizers.aspx

their like you were saying about the snake oil some people swear by them some think their worthless. I dont like drilling holes in the lower unit area.I ve seen a couple that broke off the cavitation plate. If their so great why dont the mfg's put them on from the factory?

 

[rrrestorer]

We used to put them on inboards to make em "pop" the boat out of the water and plane better. I suppose they will do the same thing on an inboard , if you are almost to that point of planing. If you don't have enough power to keep it on plane then it won't work as it also creates more drag, like trim tabs.

 

[MikeP]

Gotcha! Thanks...guess we're buying a 15HP then.

 

[newinlet]

Mike the fins do help but the new 15 will work better, 02 worth

 

[C. Edmund]

In a dink, positioning of people is far more important that any other factor when it comes to planing. If the boat speed is just not what you need and the engine labors, then you need a bigger one.

I would think your engine would be enough for that boat though.

 

[MikeP]

We've tried positioning changes but what works best still won't plane except on rare occasions - just two adults and neither of us is very heavy.

For most of what we do, it doesn't really matter because we usually anchor pretty close to whatever dock/resturant/bar etc that the dink will be tied up. But on some occasions, where we anchor is a mile or two from our destination and it's nice to be able to get some speed more than a fast walk.

 

[SportFishCruising]

General consensus from guys I've asked on tournament bass tours who have them say it gives them a better hole shot to get on plane faster. My son bought a bass boat with one mounted on a motor I thought was too small, but it jumps on plane and stays there very efficiently. Add this 2 cents to the kitty

 

[REBrueckner]

11 ft RIB plus two adults and a fuel tank means a 6HP engine IS small for planing. A 15 HP should do the job very nicely, even a 9.9 if the 6 is so close.
Once you can get up on a plane, you might find you'lldo a lot more exploring, especially of nearby harbors you might not bother to visit in the big boat.

My favorite pastime was anchoring for several days or even weeks and using my 11ft Whaler to explore....I'd even be gone on occasion for three or four hour trips exploring other harbors,towns, islands,talking with locals, shopping,etc. My dog loved it as much as I. She'd sleep for hours after a long trip!!!

One example you might know, Mike, is Port Jeff..anchoring there I've Whaler'd to both Stony Brook to the west and Mount Sinai to the east...a LONG run without planing....only twenty minutes or so each way with a 15 HP....

 

[MikeP]

"One example you might know, Mike, is Port Jeff..anchoring there I've Whaler'd to both Stony Brook to the west and Mount Sinai to the east...a LONG run without planing"

Yep, know that area well as part of our old stomping grounds! And yes, puttering along at RIB displacement speed is a total PITA.

 

[Pascal]

Mike

give the doelfin a try. I ve tried with and without on varous Dinka and it makes a big difference. It should be the extra bit of lift you need

 

[SeaEric]

Mike, I have a Tohatsu 10 HP in stock if you'd like to try it. When are you back to K.I. ?

 

[scary]

15 hp two stroke. The older Merc 15 is based on the 9.9 ( weighs the same) and offers a lot of punch for the weight. I think you need the extra Hp to plan at over 20 mph. The 15 will probably plane the Avon with four average people and give 25-28 mph with just two. The older Mercs weigh about 78lb. I've had mine for 16 years wouldn't part with it.

 

[Passages]

Yep, I owned a 11' Avon RIB with a 15 hp Merc 2 stroke.

With no fins - Could plane 2 adults & 2 kids no problems. Top end with just me and my handheld GPS was 27.

I did not need (or want) to go any faster in that little thing.

 

[MikeP]

Eric,

I'll be there on Aug 16; Yeah - trying out a 10 would be a good thing.

 

[Colwyn D]

For comparison I have an 11' Novurania RIB with a 9.9 Yamaha 4 stroke. It will plane easily with 2 adults on board but not with 3. You may want the 15hp. I also have the fins fitted but have not used the outfit without them so can't give an opinion.

 

[OBXTucker]

I've owned many small boats with Outboards and swear by the fin type products. They WILL get you up on plane faster, but only if you have enough horses to get there to begin with.

I've got them on my 13' Nouvarania w/ a 50hp Yamaha and she jumps on plane in less than 2 seconds. This helps immensely in shallow areas, such as the Currituck Sound, where I used it this weekend for tubing/wakeboarding with the kids.

Get the largest motor the rib will handle. You won't regret it.

 

[DLCameron2]

Hi Guys:

Our "new" 1987 Sea Ray Pachanga has a Doelfin (not sure about the spelling). Mike - I am amazed at the response of the trim and how the boat jumps on plane. As Pascal says I would give it a try, of course as you already know there is no substitute for cubic inches/horsepower. Have fun and see you in San Miguel!

DC

 

[LUV'N LIFE]

Mike, We have a 11' Caribe center console with a 30HP honda and Doel Fins. Before I installed the fins it was always nose in the air to plane with just me in the boat. After the fins were installed I can pop on plane and never lose sight of the water in front of me. That is where I appreciate the fins.

 

[Beckytek]

I have an 11' Achilles with the 5 hp Tohatsu. I can get on plane by leaning forward and full throttle. Thats with the wife on board. With more than 2. it won't. Ron