Prop suggestions?

[packman35]

I have a 93 Four Winns Freedom 180 with Evinrude 115. The factory shipped this boat with a 13x19 prop on it but the PO changed it to a 13.5x17 which is chewed up quite a bit. It looks like the PO had several encouters with the bottom! I am looking to get a new prop and looking for suggestions.

I'm looking to achieve (in order of importance)

1. Better handling
2. Fuel Economy
3. Pulling power (for tubes - no skis as yet - kids too young)
4. Speed

Right now with the 17P prop, I am getting WOT of 5500 and around 37 MPH GPS with two adults and two kids. The engine is rated for 4500-5500 WOT.

Any suggestions for a good aluminum prop? I would consider SS but they are a bit out of my budget right now (unless they are "significantly" better than aluminum so I can justify the extra cost).

Thanks in advance for any advice or suggestions.

 

[Silvertip]

Re: Prop suggestions?

You make every prop guru smile (or in some cases shake their head) with your request:

1. Better handling (please explain this as it too generic)
2. Fuel Economy (you own a boat -- you will not change fuel economy any significant amount with a prop change).
3. Pulling power (for tubes - no skis as yet - kids too young)
4. Speed

Now #3 and #4 is where the humor enters the picture. Think about your car or truck. If you had to pull anything really heavy what would you do? You need to select a lower gear right? With that in mind, if you continually drove in that gear (pulling something or not) what would happen to your fuel economy? It would be dismal to say the least would it not? Now back to your request. A boat has no transmission so the prop needs to get you moving and provide optimal speed and pulling power -- all without shifting gears. So #3 and #4 are mutually exclusive -- you can compromise on speed to give you the pulling power you need. Or you can compromise on pulling power to get the speed you need. You just can't have an optimum situation for both parameters - that too is called compromise.

Since your engine is already running at the recommended WOT rpm WITH a chewed up prop, I would suggest you stick with a 17P. I do not recommend props because I get into enough trouble without telling someone to use brand "X" or "Y". Some props work well on certain hulls and engine combinations and that same prop may be terrible on another. However, in this case, and with a fair understanding of your needs, I would suggest you check iBoats prop offerings. There are many good aluminum props with Hustler claiming near stainless performance at an aluminum price. Solas is another respected brand. Here's the link:

http://boatpropellers.iboats.com/Ev...andard&**********=435821370&*******=304763741

 

[packman35]

Re: Prop suggestions?

Thanks for the reply. Let me clarify:

1. Better handling - right now, I don't feel like I am getting a good bite with the water. Feels like it is slipping. Maybe due to the chewed up prop, maybe due to the prop quality. I have read posts that say that better props give better handling, particularly in turns.

2. Fuel economy - I know boats burn fuel. Especially my 2 stroker. I am hoping that perhaps by choosing a more efficient prop, I can lower my RPM a bit and hence, save a little fuel. So I guess I am looking for a good efficient prop.

3/4. I know these are mutually exclusive. That's why I listed them in order of importance to me. I know a the 17P will give better hole shot and the 19P better speed but am looking for input for a good prop that is efficient and gives perhaps a good compromise of the two.

So to rephrase my question, any suggestions on a good (the best?) quality prop that will be efficient and give me good performance?

 

[Silvertip]

Re: Prop suggestions?

I will try this one more time. Adding pitch will cause engine rpm to go down so you don't want to do that since the RPM is correct with what you have. Any slippage or lack of bite as it's called, can probably be blamed on the chewed up prop. yes -- there are better "quality" props. Stainless props are generally better "quality" than aluminum but there are some very good performing aluminum props and some poor performing stainless props so quality becomes a rather odd term to use when measuring performance. Since you did mention money was an issue, my recommendation is still the same -- Hustler or Solas. As for efficiency, perfect efficiency is a prop that has 0% slip but that is an impossible goal as the prop operates in a liquid so there will always be some slip. Slip being the difference in theoretical speed vs actual speed. To simplify that statement, consider that a 17P prop "theoretically" moves the boat forward 17 inches with each revolution. Actual movement would be something on the order of 15.3 inches (10% slip) or 14.45 iinches (15% slip). Generally, a stainless prop will have more bite because the blades flex less than an aluminum. A certain prop designs can also be run higher (as in engine mounted higher on the transom) than others so that's another factor to consider whether you run a AL or SS props. Are you getting the idea why this is not a cut & dry situation. Dhadley will probably pass by soon. He and others have tested more props than I've likely seen so they would be the dudes to make a specific recommendation based on their experience.

 

[Bondo]

Re: Prop suggestions?

I know a the 17P will give better hole shot and the 19P better speed but am looking for input for a good prop that is efficient and gives perhaps a good compromise of the two.

Ayuh,... Try an 18", 4 blade...