How are the small single cylinder Copperhead motors able to spin such a large prop? The prop on my motor is 10" and a little.

My little boat with the 12hp LCT will consistently run between 27-28mph wot and cruise easily in the upper 25mph. The boat is not heavy at all, 12' overall and 44" at the bottom and roughly 56" beam. Just me, 170lbs, 3 gal of fuel, small 26qt ice chest with ice and drinks and a small U1 deep cycle battery. 2 of us loaded the boat in the truck and then unloaded it onto the trailer. I am guessing maybe 225 - 250lbs bare boat and then factor in the 125lbs for the motor. It took several trips to the lake to dial it in, getting the trim tab bent far enough to correct the porpoising.

The boat is too fast for me, it is a bit frightening to me, especially running up the river. I am buying a 7hp to try out, if it will plane out and carry what little I want, I will be happy.

If the 7hp doesn't work, can I drop the pitch on the 12hp to slow the motor down? Any other ideas?

1244 Atchafalaya Outdoor Designs W/ 12hp Copperhead

Im sure you can prop it or gear it. Many would love to have your problem

Run prop thru sand for little while, it will slow down!

Add cup to the prop to increase load carrying and take a little pitch out to lower speed. Do both, to keep rpms from getting too high.
Or put a throttle stop so it won't go full throttle, and be able to remove it when you load up the boat if you want more fuel.

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You could also just toss an anchor or drift sock in the water when you're running lol

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I love the way the boat rides, but when it is running any where above 20, it's almost impossible to turn, it just skates across the water unless I really lean in to the turn and then it still won't bite consistently.

If I drop below 20 and remain on plane, it will turn easier, but still is a crap shoot, drop below 15 and as long as it remains on plane it becomes easy to turn as long as I use my weight. I haven't had anyone else out with me in another boat to see exactly how deep it is riding at those speeds.

This is the bottom of the boat:



I also considered some form of a strake, since shallow water and laydowns are about my only obstacles, but I don't want to "ruin" the boat, wondering if they will help at all.

If I decide to add cup and lose pitch, can someone point me to someone that is familiar with the Copperhead props? There is a prop shop locally, B&B Propeller, but have no clue if they have ever touched a surface drive prop.

1244 Atchafalaya Outdoor Designs W/ 12hp Copperhead

Laprop can fix you up.

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You don't have to run at full throttle if it's too fast. Just let off.

So, you are complaining about going to fast and you want to go slower?
you are the opposite of every other person on MMT.

My boat is slower than yours and turns better! Let's swap rigs!!!!


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Darryle I bet some stick time is going to be the best thing for your problem. I just got a little boat a couple months ago and it was real sketchy at first. After several dozen hours in it i'm learning little tricks on how to make it steer better, run better etc. when I'm with someone else in another boat I'll try and push my limits a bit just to see what i can and cant get away with. I try to not over do it, just push it a little. In a few months you'll be on here asking how you can get more speed out of that copperhead.

You can get a 10x8 hill prop and try it out. Doesn't have near as much cup as a copperhead prop.


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Here is the current prop, IIRC it is a 10x8

1244 Atchafalaya Outdoor Designs W/ 12hp Copperhead