Axis Wakeboard Boat Forum

I came across this formula for HP loss at elevation. I'm not sure if its accurate but I've seen it quoted in several places.

HP Loss = (elevation x 0.03 x horsepower @ sea level)/1000

Please feel free to comment as I don't wish to pass on bad info.

So 1000' of elevation is 3% loss in HP?

Seems about right. Equates to 30% loss at 10,000'.

Might be a underestimate in the loss. I've always heard about 30% loss at Denver area, ~5000'


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You are WAY overstating things (even though it might feel like 30%) through the butt dyno.

The 3% rule is just a rule of thumb and obviously isn't linear. You don't keep subtracting 3% from the original number for every 1000'... rather, as you increase, for every 1000', you have 97% of what you had 1000' ago. If you just keep taking 3% from the original number then you'd end up with negative horsepower at 34000', which is obviously wrong given the altitude records for internal combustion aircraft are close to 60,000'.

I'm just wondering out of all the people that are having a problem getting on plane with full or nearly full ballast for wakeboarding speed have the FAE on their boat?

Do not. Although I noticed a lot of turbulence from someone that has one of theirs shooting up through the wedge access panel, is that normal?

I have a 2016 T23 w/ 350, running the Acme 2315 prop and looking for the best surf wake. I have 825 pnp in rear and 2 650 pnp in bow.

Should I be switching to the 2773???

Nick, your prop pitch isn't really going to affect your surf wake shape per se, at least not to a noticeable degree. If anything it will lower your RPM at surf speeds which should help you on gas, but still be enough power to get you to surf speed with ease.