Planing a dinghy with 3.5hp

[Gaia]

Originally Posted by Ida_Lewis

I’ve got to say I love my Torqeedo 1003. Weighs ~ 30 lbs overall, comes in three pieces which are easy to assemble in the dinghy, and you can get a spare battery if you want. There’s a readout on the tiller telling you how much juice you have left.

No planing, but I am happy to forego that if I can avoid carrying gasoline. To store, just hose it off and put it in its case. Done!

Also, it’s quiet, so you can actually converse in the dinghy.

Different strokes for different folks I guess. I detest my Torqeedo. The hype is overdone.. I can plane our 12 ft Tinker dinghy with an old 3.5 two stroke with rattling bearings easily but with the Torqeedo, 1003 rated at 3 hp I believe, nothing a chance. After very few hours of use water got inside the motor, 700$ to repair. And I have two batteries for the damn thing. Going to sell cheap. Now have a new 3.5 Tohatsu and planing, which I normally do not care for because we like things quiet and peaceful, is no problem at all.

Jim

[Hunky Dory]

If you plan on buying a dinghy think about the Walker Bay with a inflatable collar. You can buy the sail kit and have fun to, I have the 8 ft and have passed many a sail boats with my saiing kit. Love the looks on the sailors faces when a plastic wash tub has better performance then their boatsl.

[mikedefieslife]

I'm not sure why people think it's so difficult to plane a small dinghy with a 2.5/3.5 motor.

My Mercury and my Marinier 2.5 (with restriction removed to make it 3.5) would plane my 2.6m 33kg inflatable dinghy up to 8knts in perfect conditions, more like 7knts in others. It would not plane with 2 people though.

There is a British magazine test of dinghies less than 3m and IIRC nearly all of them would plane with the 2.5hp motor

https://www.mby.com/gear/the-ultimate-tender-test-26057

[Robert E]

Originally Posted by lancelot9898

I plan on getting a 10 ft inflatable floor dinghy and because of weight restrictions on the outboard, using only a 3.5 hp. Is there anyone out there that can get the boat on plane with such a small outboard? I prefer getting a 6 hp motor, but the weight is close to 60 lbs and I don't think I can handle that without a crane. There are some 2 stroke outboards on sale on Amazon which weigh in at 40 pounds, but unsure of the quality. Didn't even know that it was possible to buy here in the US. Any comments about these outboards made in China?

We did a lot of investigation to find a dingy and smallest 4-stroke that would plane with the two of us. We weigh 320 lbs. A 6hp Tohatsu and Achilles HP280LX were our choice and we are pleased with the combination. Best of luck. Bob S/V Shamrock, Nonsuch 33

[roland stockham]

If going for low power you want to make the boat long, thin and rigid to increase efficiency. For example a canoe with a transom will make 6kn using an electric trolling motor. Planing boats are inherently inefficient at lower speeds so think about boats designed to paddle or row, accept the lower speed and really enjoy the benefits of a low power hull. (light, quite,low cost, environmentally friendly etc) Why, after all, do we need to do 10kn+ to get from the boat to the jetty when we are happy to cross an ocean at 6kn?

[alaskaflyfish]

I have a brand new Mercury Hypalon 8 foot airfloor. I have a brand new Tohatsu 3.5 four stroke and an older 2005? Mercury 3.3 two stroke. The 2 stroke is much lighter and easier to carry with the attached handle. Both motors perform equally. Planing is just one person sitting in the middle/forward with a long tiller handle attached. I can see where a hard floor dink would be superior for planing. My personal opinion is that the newer 4 stroke engines are just too heavy to manhandle in certain conditions. Otherwise they are good engines. At first I thought I would sell the 2 stroke but after using it last summer on the dink I have decided it is the best option for the inflatable. In fact, if I could buy a used 5hp 2 stroke, I would. Concerning Chinese made outboards, Ive heard nothing but horror stories. Bad warranties and lack of parts. You get what you pay for.

[Hardhead]

I'd try to add some after-market planing fins (or whatever they are called) to the outboard cavitation plate. Might be just enough lift to make a difference in some circumstances.

[lancelot9898]

Originally Posted by mlaver

My 8' 6" Avon (wood floor, inflatable keel) will plane reliably with a Nissan/Tohatsu 3.5hp 4-stroke long shaft if it's only me onboard. I have gotten it on plane with 2 people but only in very flat water and a fair amount of juggling of seating positions.

Do you think that long shaft is better on the dinghy? Did you specify a higher pitch prop?

[lancelot9898]

Originally Posted by Robert E

We did a lot of investigation to find a dingy and smallest 4-stroke that would plane with the two of us. We weigh 320 lbs. A 6hp Tohatsu and Achilles HP280LX were our choice and we are pleased with the combination. Best of luck. Bob S/V Shamrock, Nonsuch 33

Do you use a hoist for that 6 hp and if so what did you go with?

[ShipOfFools]

Originally Posted by lancelot9898

I plan on getting a 10 ft inflatable floor dinghy and because of weight restrictions on the outboard, using only a 3.5 hp. Is there anyone out there that can get the boat on plane with such a small outboard? I prefer getting a 6 hp motor, but the weight is close to 60 lbs and I don't think I can handle that without a crane. There are some 2 stroke outboards on sale on Amazon which weigh in at 40 pounds, but unsure of the quality. Didn't even know that it was possible to buy here in the US. Any comments about these outboards made in China?

Hey i attempted something similar last year and plan on upgrading my inflatable this year. I bought a 2.5 HP suzuki and a hydroforce inflatable. it works well but doesnt go above 10 mph.

[lancelot9898]

Originally Posted by ShipOfFools

Hey i attempted something similar last year and plan on upgrading my inflatable this year. I bought a 2.5 HP suzuki and a hydroforce inflatable. it works well but doesnt go above 10 mph.

What inflatable are you considering? 10mph should put you on plane?

[Paul Howard]

I had a 3.5hp 2cycle Mercury that would get my 9' aluminium hard bottom inflatable up on the plane with just me onboard if I sat way forward. That engine died and I got a 4hp. 4cycle Tohatsu and the same dinghy would not get up on the plane with that engine.

[ShipOfFools]

Originally Posted by lancelot9898

What inflatable are you considering? 10mph should put you on plane?

i have a long list of requirements on my original thread. i was thinking of upgrading to a takacat or similar inflatable catamaran

http://www.cruisersforum.com/forums/...ed-202007.html

[Montanan]

Video of a dinghy with Lifter tabs installed to aid in planing. It worked well for this 260 pound guy, 8.5 foot dinghy, powered by a 1978 Johnson 9.9hp engine.

https://www.youtube.com/watch?v=xrIehHGrEW0

[ShipOfFools]

Originally Posted by Montanan

Video of a dinghy with Lifter tabs installed to aid in planing. It worked well for this 260 pound guy, 8.5 foot dinghy, powered by a 1978 Johnson 9.9hp engine.

Awesome stuff! do you think these would work on an inflatable catamaran?