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-   -   Bam marines prop slip calculations aren't right (https://www.offshoreonly.com/forums/general-boating-discussion/85983-bam-marines-prop-slip-calculations-arent-right.html)

blackhawk 08-26-2004 07:42 PM

Bam marines prop slip calculations aren't right
 
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.

Payton 08-26-2004 07:59 PM

Re: Bam marines prop slip calculations aren't right
 
Maybe they were going down river with GPS.:):

blackhawk 08-26-2004 08:36 PM

Re: Bam marines prop slip calculations aren't right
 
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.

Mbam 08-27-2004 06:26 AM

Re: Bam marines prop slip calculations aren't right
 
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.

IceAngel 08-27-2004 07:04 AM

Re: Bam marines prop slip calculations aren't right
 
To get your slip number take actual speed divided by theoretical speed

Mbam 08-27-2004 07:11 AM

Re: Bam marines prop slip calculations aren't right
 
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

blackhawk 08-27-2004 07:32 AM

Re: Bam marines prop slip calculations aren't right
 

Originally Posted by IceAngel
To get your slip number take actual speed divided by theoretical speed

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!

blackhawk 08-27-2004 07:34 AM

Re: Bam marines prop slip calculations aren't right
 
Marc, works perfect!


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