Prop selection

Fishin 911 · Post by **Fishin 911** » October 13th, 2003, 7:46 am

I am not properly versed on selecting the right pitch prop. I run a 13.5 inch prop, and I believe it is a 19 pitch..cant really remember. I think that when I put it on 3 yrs ago..I ordered the wrong pitch. I want to know what pitch I should run.

I am only turning 4500 RPM WOT with minimum weight in the boat. With the older prop I remember turning 5500 RPM. I am running a 85hp Yamaha on a flat bottom skiff. I really dont want anymore speed, but I feel I am not getting optimum preformance out of it.

What pitch do any of you reccomend ? I am going to run aluminum prop instead of stainless due to cost and I operate in shallows subject to rocks, etc.

Post by **Tom Keels** » October 13th, 2003, 8:11 am

You need to go to a 15 Pitch on that motor and make it turn about 5600 RPM at WOT. We turn a 13.5 X 17 on the 17 key west with the 90 on it and and turn 5600 RPM WOT.

Post by **Sir reel** » October 13th, 2003, 8:58 am

FishinFool,

I've got a 13.5 with the 15 pitch that I carry as a spare. I'd be glad to let you borrow it to see what it does for your preformance before you buy .... in case your interested. I've also got a 17 pitch but it will need some attention from the folks at RMS before you could run it

Fishin 911 · Post by **Fishin 911** » October 13th, 2003, 2:32 pm

I'll get up with you about that. Would like to see how it does.
Thanks

I am going to need to purchase soon....my current prop has a bur on the end that a dremel will straighten out. I want to make it a spare before it gets too thin and breaks or gets beyond repair.

Post by **tin can** » October 14th, 2003, 5:56 am

Sounds like you're about to go at this in the proper manner. Try different props until you find the one that runs around 5500-5800 on your boat. Sir Reel has made you a very generous offer. I would suggest you borrow his 15 pitch, run it...................through a couple of oyster bars to insure it's durability, and give it back to him.

SR, you're a nice guy. Can I borrow your boat for a few months?

dstockwell · Post by **dstockwell** » October 14th, 2003, 6:47 am

With friends and advise like that from TC, who needs enemies.

Post by **tin can** » October 14th, 2003, 6:48 am

Don, can I use your rig for a few months?

Post by **wevans** » October 14th, 2003, 6:58 am

You can use mine TC, but ya gotta take me with it

dstockwell · Post by **dstockwell** » October 14th, 2003, 7:00 am

Yea what wevans said.

Post by **tin can** » October 14th, 2003, 6:30 pm

Don and Wevans, I can do that.

Post by **CSMarine** » October 15th, 2003, 7:34 am

TC, your more than welcome to use mine, but you'll have to use a paddle to steer it with. My steering went out Sunday.

(Bad cable=stripped rotary unit) All I ask is that you bring it back fixed.

Post by **tin can** » October 15th, 2003, 5:44 pm

CS, thanks for the offer. However, I own two boats and it's all I can do to keep them floating. What I realy want is for someone to loan me their boat, and when it breaks I'll give it back.

lightchop · Post by **lightchop** » October 16th, 2003, 10:14 am

ff,
I'm a little curious about your question, in that, it's a universal one for fishermen. I looked over the stuff on the thread and I didn't notice any mention (it could be I haven't had my second cup of coffee, yet) of the Yamaha specification for the RPM at WOT for your motor. You say the old prop did 5500 RPM and someone else mentioned 5600. My point, without anyone thinking I'm criticizing anybody, is that the manufacturer, almost always, specifies a certain, usually maximum RPM at WOT for each motor, since that is, like a max redline RPM for that motor design, i.e., it varies, usually, somewhat with each motor. Prop pitch and diameter, of course, as we all know, can be varied to achieve the SPECIFIED max RPM, which will vary due to boat load, hull condition, etc.
Luck with your selection (if it'll be a SS prop, you know it's $$$).

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