Propellor Pitch

[reicherb]

I've got 2 Props. (1) 13 3/4 x 15 and (1) 13 3/4 x 17. Which will give me more top end and which will give me more out of the whole?<br /><br />Thanks.

 

[ThomWV]

Re: Propellor Pitch

15 for the hole shot and the 17 for top end. What the number refers to is how many inches the prop would theoretically move forward in one revolution without slip - like a screw into wood. So a higher number means more inches per revolution which really means more miles per hour. However if you go down in pitch what you give up in speed you gain back in accelleration, or hole shot. Everything is a tradeoff.<br /><br />Thom

 

[achris]

Re: Propellor Pitch

Check out this post in the FAQ section. Just read it and it's very well written.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000030

 

[rickdb1boat]

Re: Propellor Pitch

But remember, the 17" will only give you more speed if your motor has enough ummpphh to make use of it...

 

[fishhawk16]

Re: Propellor Pitch

Ideally wouldn't you want to have the correct prop on the boat to reach max RPM at WOT? <br /><br />My understanding from other posts are if you have too much pitch the motor will be working to hard and cause damage, and carbon build up. Not enough pitch you could be over reving you motor also causing damage.

 

[achris]

Re: Propellor Pitch

Fishhawk - you're spot on!

 

[JasonJ]

Re: Propellor Pitch

Fishhawk is right. Another factor should be to prop for the intended use of the boat. If you are a loner fisher like me who rarely takes anyone else out on the boat, you can run a higher pitch because you are not carrying as much weight. Conversly, if you are taking the wife/kids/three buddies/anvil collection all the time then you will want a lower pitch. Key is keeping the engine at the upper end of its recommended rpm range with the most commonly seen load in the boat. The more horsepower you have, the less load sensitive it is though, so that is another factor to consider. I have 125 horses on my 16.5 foot boat, so there is almost no performance difference when loaded, but someone with a 50 horse will see dramatic differences with varying loads.