Bob & Mag

Here's a site with a prop calculator for those that may be wanting to re-prop or guessing the effect of different pitch props.

Based on two props I used the last summer on our 90 e-tec, it's pretty accurate.

http://go-fast.com/Prop_Slip_Calculator.htm

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Smoke free 8+ Months!

Bryan A.

Thanks. My 25' could use some prop work. It is a little underpowered at the moment and I always felt it needed a better prop. I'll have to play with the numbers.

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2003 Parker 2530 "El Mar".......click the pic
1973 Seacraft 20SF

CaptDom

Messing with outboard props is pretty easy, You know from the manufacturer what diameters you can swing, and what pitch will work based on your operating parameters. They give you all the options, and most will explain what each will do in terms of affecting high end or low end power.(hole shot vs. top end, etc.) That calculator will work fine with an outboard setups, but I wouldn't dream of using it to tweak a prop on a straight shaft.

With straight shaft boats, go to a professional!! You can mess with diameter and pitch quite a bit more with these type of inboards, and you can affect things much more even with small adjustments.(things like harmonics, tip singing, cavitation, and lots of other nasty little problems) I had several experts use their calculators with an old boat, and wound up screwing it up big time.(huge expenses with hauls and new props after the old ones were pooched) You have to take alot more into consideration with this set up, like hull configuration, tip clearance, speed vs,\. rpm, underloading and overloading are alot more likely when fiddling based on just a mathematical formula, never mind the little problems which could nag ya.

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CAPT. DOM PETRARCA
COASTAL CHARTERS SPORTFISHING
NEWPORT, RI (401)-862-0358
www.coastalcharterssportfishing.com