Anyone notice that Bam marine's website has the wrong prop slip formula? And their calculator is wrong if you plug in your actual speed and hit the calculate button under slip.

I don't know if it's always been like that or something got screwed up. But I started playing with the numbers and noticed it. Both the formula and the calculator will give you higher slip readings than what you actually have.

Maybe they were going down river with GPS.:

LOL

No, I'm saying the actual numbers don't add up. According to my math it should be theo sp - actual sp divided by theo sp(not actual sp) to give you prop slip. Their calculator figures it that way too.

Yep, it is wrong, turns out to be a couple of percent. It's still useful, as the actual hard number is not as important as the ability to plug in the changes. I have been meaning to fix it, so this might be a good time.

To get your slip number take actual speed divided by theoretical speed

Should be fixed, boy I am much better at this web stuff then when I first built the site.
Please try it and let me know
Thanks for the heads up

Actually, to get your slip you take the difference between theo speed and act speed and then divide it by theo speed.

So, if your theo sp was 92 and actual speed was 76 you would subtract 76 from 92 and get 16. Now divide 16 by 92 and you get .1739 or 17.39%.

Mbam, thanks for confirming I drove myself nuts for a few minutes until I figured it out!

Marc, works perfect!