Planing with a 6HP...what are my options?

[srileo]

Hi all,
New forum member here!
I have a new Yamaha 6HP paired to a 10’ SIB with air floor. I just finished the break in of the motor, but am struggling to get it to plane with 2 normal adults. The bow just rises and stays up. We are averaging 6mph WOT at displacement speeds with 2 aboard. No fun at all.

I tried a few runs with just myself aboard clocked about 14mph once. I liked the feeling of a boat on plane - smooth and level (my first time experiencing it!)

I saw this YouTube video of a guy with a 6HP motor and he is able to plane 2 up on a 12’ boat with a prop change.

Trying to mimic his results with a similar prop change, I checked my stock prop. It is a 3 blade 7.25” x 8.25”. 
Knowing that I’d rather get on plane sooner with 2 adults if possible and sacrifice top end, what size OEM prop should I get? The Yamaha choices are 7.5”x7” or a 7.25” x 6.5”. My 6hp is rated for 5500 rpm. 

I’ve ordered the 7.5”x 7” prop and looking forward to trying it out this weekend.

Another issue is that of transom height. My boat is 15” transom and the outboard short shaft is 17” to the top of cavitation plate. I’ve read that the cavitation plate should be level with the keel. In my case I am 2 inches below. I’ve tried using a small wood block to raise the outboard but don’t feel and difference in speed or handling. Should I just return back to stock?

Finally, should I think of hydrofoils at this stage or is it too much for such a small motor?

Thanks for the advise!
Shridhar

[Stray]

Try redistributing weight, get the 2nd person as far forward as possible.

[Si Crowe]

Hi Shridhar and to the forum!

Planing with 6hp is totally possible 2 up of you are both light! (I doubt I could plane solo with 6hp)

I wouldn’t worry too much about the height of the transom - if you can put a block under it and it doesn’t ventilate then keep running with the block under it. It won’t make much difference to your speed, but it will reduce the amount of splashing.

@Si Crowe recently had great success with some home made trim tabs.

[srileo]

Yes, the my friend is almost sitting on the bow. When alone i tried sitting in the middle of the boat. Jsut ordered a tiller to make that easier.

Try redistributing weight, get the 2nd person as far forward as possible.

[srileo]

Good to know about the transom. I'll leave out the wood blocks then, its just another thing to go wrong in the long run.

Yea, i am 80 kg and so is my friend. Nothing else but gas and beer on board, so am hoping we should plane easier with the new propeller. No fun plodding along at 6mph and a lot of noise.

Hi Shridhar and to the forum!

Planing with 6hp is totally possible 2 up of you are both light! (I doubt I could plane solo with 6hp)

I wouldn’t worry too much about the height of the transom - if you can put a block under it and it doesn’t ventilate then keep running with the block under it. It won’t make much difference to your speed, but it will reduce the amount of splashing.

@Si Crowe recently had great success with some home made trim tabs.

[Si Crowe]

i have a little 2.4m airdeck with a 5hp 2 stroke and had the same issue, either bow up and slow or flat out and planing. i wanted to have a bit of help getting on the plane easier so made some trim tabs...

easy to make and worked a treat, 2 up i can plane easily and with just me she pops up and flies at about 14kts.

i made them so i can just the remove the turn buckles and fold the tabs up against transom for storage.

[DavidA]

I think you will have answered your own question. Your boat you say is 10 feet long yet in the video the boat is 12 feet long. The longer the boat the easier it is to get on the plane as the extra bouyancy helps keep the boat level and less inclined to dig in.
I have a 6hp Yamaha Four stroke and on my Honwave 2.7 found planing quite difficult, however with the same engine on my Honwave 3.2 planing is now a breeze, even two up with forward weight distribution.
Your gonna need a bigger boat!

[Bigplumbs]

While many get a boat to plane with a 6hp I think it is very marginal and a 9.8 (say 10 hp) is the smallest you should ever go........ but I am sure many will disagree

[Essexkayak1]

My honwave T32 and 6hp planes easily with just me.
I was out last weekend with a friend and we got 12 knotts on very calm water with one of us sitting at the front. I am 14 stone and my friend is about 9 stone