Question to help find spare/new prop.

[MDJ1016]

1986 Four Winns Liberator
260 HP 350
Alpha 1 Drive
Gear ratio- Told it is ?1.5?; is there a great way to verify?
WOT is to be between 4200-4600 RPMs
Currently boat runs 4500 RPMs and about 47 MPH (GPS) on a clear, smooth day.
Boat weight (aside of fuel, occupants)- 3100 pounds
So my question is am I at the ?top end? speed or should I expect under normal, non modified conditions for this boat more? It is a big deep ?v? so I fully understand it is not a race horse here. From what I read one must make the decision when selecting prop either out of the hole acceleration or top end speed. (I am torn between these two now.)
Follow-up question is would it be a smart choice to use a 3, 4 or 5 blade prop? We use the boat to cruise in (yes, I run it at top speed a lot with the friends in boat) and then use it to dive (scuba) off of.
Any help would be appreciated.
I am considering (once new prop is identified) to purchase aluminum to try, and once I find that ?perfect? scenario then purchase an SS version.

 

[Bondo]

Re: Question to help find spare/new prop.

Ayuh,... It sounds like the boat is set up as Good as it gets...

 

[JustJason]

Re: Question to help find spare/new prop.

Yep as Bondo says, your right on the money.

As far as # of prop blades.

3 Bladed prop - fastest top end due to reduced drag, worst hole shot and worst handleing charectorists
4 Blades - slower top end because of more prop drag, better hole shot because of better "grip" (more prop in the water), better handleing
5 blades - slowest top end, best hole shot, best handleing ---- expensive

For the average joe boater, most people run 3 bladed aluminum props.

 

[steelespike]

Re: Question to help find spare/new prop.

I agree you are about right on. A carefully selected 4bld can come close to giving you both hole shot and a respectable top end. Member hwsiii has a long form you can fill out and he can usually make a very close suggestion for the best prop.
If you look for his posts you can find it.
Setting up with an al. prop and changing to ss isn't likely to work.
To many variables.You may be able to find a dealer that will let you try
props and exchange if you intend to buy from them.In that case if you want ss then test with ss.There are some very good aluminum props that perform close to stainless.If you boat where you are likely to make hard prop contacts you may want to stay away from ss.They can transfer forces to the gearcase more than al.
If you boat where soft contact is probable the stainless will hold up better than aluminum.Of course stainless costs much more to buy and repair.

 

[MDJ1016]

Re: Question to help find spare/new prop.

Thanks for help.

From what I have read it appears the boat should have a 17 pitch on it.
On the prop today I found this engraved on it-
"48 7398045 19P"

So I assume now that this is a 19 pitch prop.

Maybe a 17 pitch is the key......

 

[trendsetter240]

Re: Question to help find spare/new prop.

Thanks for help.

From what I have read it appears the boat should have a 17 pitch on it.
On the prop today I found this engraved on it-
"48 7398045 19P"

So I assume now that this is a 19 pitch prop.

Maybe a 17 pitch is the key......

Yes, if it has 19p stamped at the end of the model number it is an 19" pitch prop.

Sounds to me from your first post that you really want high end performance and to stretch that last few MPH out of your boat. If you want this the only way you will beat what you've got is with the right SS prop.

Most Alum. props won't give you a huge difference from what you see now in top end. A 17p is going to raise your RPM but that doesn't always translate into better top end speed.

If you just want a spare then I'd go with a 17p 4blade alum. prop. This would be much better for water sports and hole shot but probably drop a few MPH of your top end. You can use the 19p for the long runs out to the dive spots and the 17p for water sports and heavy loads. Either one can be a spare.

As mentioned, if you can find a dealer that will let you try out some SS props on your boat you should be able to get a few more MPH and a few more RPM with the perfect prop.

 

[MDJ1016]

Re: Question to help find spare/new prop.

No water sports behind this boat. Hate to say it but speed is # 1. More I think about it hole shot is nice but over a long run speed will be the difference.

So it appears 3 blade is the "speed" prop, but what pitch to move onto?

 

[trendsetter240]

Re: Question to help find spare/new prop.

No water sports behind this boat. Hate to say it but speed is # 1. More I think about it hole shot is nice but over a long run speed will be the difference.

So it appears 3 blade is the "speed" prop, but what pitch to move onto?

Well, if you are looking for a 17p prop then I would try one of these:

Stiletto Bay Pro III 4blade Stainless 17p

Stiletto Bay prop is a nice high speed prop, the 4th blade on this on will also help hole shot and keep the rpms in check.

or

Turning Point Hustler 3blade Alum. 17p

The hustler is an aggressive prop, lots of rake and cup and will keep your RPMs in check. This prop is also vented so it will spin up quickly when you are taking off.

I have a TP hustler 17p and it definitely provides good top end speed. I have not owned a STB 4blade but have heard great things about them. The stainless will be more efficient than the aluminum because of the thinner blades. The aluminium is the less expensive option.

hope that helps.

Cheers