how fast would a 2.5 hp go?

M

michael barnes

Active member
wondering how fast a 2.5 yammie 4 stroke would push a kara hummer or similar marsh boat with 2 doz dekes, one guy and no dog, and regualr hunting gear? im trying to decide whether to build a hybrid or a square sterned hummer. a saltwater trolling motor, battery, and charger, is pretty expensive, and alot heavier than a little outboard, even the 4 stroke, plus no battery to charge and lug around, and all the run time i want and not worry about a dead battery, seems worth it.
 
I used to have something like a kara and had a 2 hp Merc on it, in glass clam water, I could go about 6 mph. Had the motor mounted to about 2/3 to 3/4 back on one side and the back of the boat was under water.
 
Michael,

Not trying to be a "smart alec" or anything but my answer is "It will push a hummer as fast as you can safely go in a hummer."

The Kara or Hummer designs have no rise, to speak of, in the bow. Depending on how you place your load you can load stern heavy, and get the bow up out of the water somewhat. If you power up and reach planing speed, the boat will level out and that won't be a good thing. If you were to cruise along at planing speed and hit a wave, you stand a very good chance of submerging the bow. You submerge the bow and the whole boat will be going under faster than you can recover.

I don't know just how much hp it would take to get your load, in a Hummer, to plane out. I doubht that a 2.5 would be over powering it. My best guess as to speed would be somewhere around 3.5--4.0 MPH. If you want to go faster, you will need to choose a design that has more rise to the bow.
 
hey thanks for the replies. like you said, a hummer that planed would be down right freaky. i just wanted to be sure a 2.5 would be enough to push me into a head wind in the shallow marshes around here. i drew a hummer style boat on autocad yesterday, but used a square stern rather than 2 pointed ends. i wont be poling it over any long distances, so a square stern wont be a problem, and will hopefully keep it floating with me and a 40 lb motor. ill definitely post pics of the drawing when a get it completely finished for opinions on the modifications.
 
Michael,

Thanks for asking a question I have some first hand info on. Usually I lurk and soak up the info on the page. I buillt a hummer about 6 years ago. I modified it with a transom because I intended to put a gamefisher/tanaka 1.2 hp air cooled outboard on her. I can tell you first hand SHE WILL DIVE LIKE A GERMAN UBOAT. It was my fault. I was day dreaming as I motored up the Winooski river. The dog was in the bow and after rebuilding that little motor and making my own boat, I was feeling pretty good. So good that I decided the dog needed a pat on the head. I was under power and took one knee slide forward toward the bow and down she went. I jumped back and killed the motor. The dog jumped out and the bow came up and out of the water. I took a good amount of water, but no real harm done. It was more of a wet education. The boat did fine under power (no chop) and I could spend all day on the water with a gallon of gas. I think a 3hp would be SCARY on a Kara. The motor I had weighed about 12 pounds and I wish I never got rid of it, but I sold it with the boat to a buddy. Also, I would recommend building up the transom at least a foot above the deck so the motor head does not end up under water if you should hit a wave that was unexpected. I hope this helps. Good luck with the build.

Cheech
 
thanks for the advice. i may look for a boat design that has a "prouder" bow. i would be hunting nearly all narrow guts, but sometimes need to cross maybe 60-100 yards of open shallow water, that can get a little bit o chop in the wind. right now im just playing around with ideas, trying to decide on a marsh boat, or if i can find a used jon or small v bottom in good shape. thanks again for the info.
 
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