16ft jon boat with twin 30hp two strokes

[matt88]

I have a 16ft x 6 ft flat bottom jon boat with the high sides and have been running it with a 30hp tohatsu. It runs fine as is with two or three people and gear it will run about 22-25mph. I have just acquired a 1956 30hp two stroke evinrude and had a hair brained idea of running both engines on the jon boat. Just wondering if anyone has had any experience with a similar setup. Would I have to have the same pitched props on both motors? I have seen twin engine setups with bigger motors on glass boats but Im not sure if twin 30hp engines would be worth the hassle. If it would turn my 25mph boat into a 40-50mph boat it might be worth it to me but Im not sure what to expect. As for the transom it already has reinforcement brackets running from the transom to the floor and if I did put the other 30hp on I would add even more reinforcements so that shouldnt be an issue. Also was wondering if I would need a left handed prop for one of the engines? And if so is it possible to change one of them to a left handed drive? Like I said this is probably more of a hassle than what its worth but I thought I would ask to see if anyone had tried it. thanks

 

[pvanv]

Re: 16ft jon boat with twin 30hp two strokes

Twin motors is usually implemented with identical motors, so to get the same power curve on each.

 

[JB]

Re: 16ft jon boat with twin 30hp two strokes

Sound like the hair-brained scheme you mentioned, Matt. I really doubt that your boat is rated for 60HP.

Unmatched twins sounds like a nightmare to rig.

 

[Blue Crabber]

Re: 16ft jon boat with twin 30hp two strokes

I really doubt that your boat is rated for 60HP.

Unmatched twins sounds like a nightmare to rig.

My thoughts exactly. I am thinking that you won't get to enjoy any more time on the water this year if you try it. You will end up spending all your time trying to make this work instead.

 

[MikDee]

Re: 16ft jon boat with twin 30hp two strokes

Having reverse rotation, is not a necessity, but having your head examined for trying to do this is!
Just kidding, but seriously,
Please be carefull, as JB mentioned, I don't think your boat is made to hold the thrust, nor the weight, of 60hp, & twin engines, a lot has to do with what the boat can handle, regardless of how strong the transom is.

 

[matt88]

Re: 16ft jon boat with twin 30hp two strokes

Oh well, I like to go outside the box to have something that is different from what everyone else has when I can get away with it,but think I will probably leave this one alone,lol. Didnt think about the different model engines having a different powerband but that does make sense to me after it was mentioned. Anyone want to trade an early 80s tohatsu for an old evinrude? I may be wrong but I think if I had identical motors I could strengthen my hull enough to make it work and be safe. I guess it doesnt matter anyways unless I was to run across a steal on another old tohatsu. Thanks for the replies and for bringing me back to my senses. Was wondering if the 22mph(gps) for a 16ft flat bottom jon and a 2 stroke 30hp sounded right? This is with two people 6 gallons of fuel,fishing gear,fiberglass floor(about 1/8 in thick),carpet,battery,lights,anchor,etc,etc..In other words full dress. Have heard some other guys claiming to get 28-30mph with the same setup.

 

[Silvertip]

Re: 16ft jon boat with twin 30hp two strokes

You might be surprised to know that twin 30's will not be as fast as a single 60. Two lower units and the extra weight results in higher drag figures than the single 60. Yes - dual and triple engines are used on some boats but that's because 900 HP single engines are not yet available. Dual engines also means twice the problems. Twin 25's and 30's were somewhat common in the good old days because 50s and 60s weren't readily available.