What would be too much horsepower?

[bmflyfish]

I am new to this forum and I was wondering if anyone else owned a Scandy White. I am wanting to upgrade my motor from my 6hp Johnson to a bigger outboard, but I do not know what my max horsepower would or should be. Scandy White's website rates most of their newer boats for 30hp, but my boat is a pre 1973 model since it does not have any id numbers nor does it have the max ratings anywhere on the boat. I would think that at the time the boat was built that it was not rated for a 30 hp outboard. I think that since outboards were so much heavier and bigger back then but I could be wrong.

Scandy White refers to their boat design as a tunnel hull and my boat is a 13ft boat. Would anyone think that a 30 hp be to much motor either in horsepower or weight? Should I just stick to a 20 or 25 hp outboard motor?

Thanks for the advice!!!

Brian

 

[Whoopbass]

Re: What would be too much horsepower?

My old 12' 1966 Klamath could handle a 25 hp so i'm sure your boat wouldn't have any problems with that size. 25hp and 35hp JohnnyRudes weigh the same. Motors still weigh the same as they did 30 years ago.

 

[bmflyfish]

Re: What would be too much horsepower?

That's cool! I always have associated size with weight. I just remember a buddy in college had a old Bumble Bee bass boat with a 50 Chrysler outboard. We use to joke that the outboard had a bigger engine displacement than his motor in his 90's model Mazda 626.

Thanks!!! Brian

 

[5150abf]

Re: What would be too much horsepower?

Again, the weight of the motor doesn't matter in determining the horsepower rating, just sitting on the boat all the weight is straight down, my boat is rated for a 70 but I could easily put a 150 on it with no problem until I put the engine in gear and ripped my transom out.

Transoms are rated for the torque the engine puts on the transom, a 30 at full throttle is putting many many times the actual motors weigh on the transom as a twisting force.

New boats have new transoms, how old is yours?

If you have not recently redone your transom it won't hold even the reccomended engine so be sure that is in good shape, you should be able to put your entire bory weight on your engines lower without the transom moving more than 1/8 to 1/4''.

On a 13' boat I woudl think a 20 woudl do very well, a 30 woudl be pretty scary if not even unsafe.

 

[bmflyfish]

Re: What would be too much horsepower?

The whole boat is solid! There is not one piece of wood or rivet in this boat. Its one of the best built aluminum boats that I have seen. But it is also a heavy boat. I do not know why I did not think of the twisting forces that the outboards make. Instead I was thinking about how the boat could be standing at attention with to much weight on the back. I just want to be able to open more fishing opportunities for myself once I am on the water. I have a 6hp and it pushes the boat right at 7mph. A small boat with LOTS OF POTENTIAL!


Thanks Brian

 

[marcortez]

Re: What would be too much horsepower?

Several outboard makes list different HP ratings with the very same engine configuration.
IE: A 15HP is the exact same displacement and weight of a 20HP.
And a 25HP is the spitting image of a 30.

For a 13' boat...no matter the "beefy" and "heavy" attributes, I personally would not go above 20HP. And a 15HP may even be a more "sane" choice.

My "dinkaround" boat is a 15' Gregor, all welded aluminum model with a 20" transom with a 25HP Honda tiller steer motor.
It will do, with me alone in the boat, 25 MPH.
At that speed, it's stable on "dead flat calm" waters yet introduce a little chop, the stability goes down, down so much that I back off the throttle.

The bow will "bite" into a chop and will "bow" steer to a point that I am uncomfortable.

I am certain that with increased chop, wakes or waves, the "bow" steer affect will most certainly cause you anguish and literally.....toss you around while your holding on to whatever you can grab.