Help with prop questions and recommendations?

lt1transam13

Recruit
Joined
Sep 9, 2007
Messages
2
Hey Guys,

Im new to this whole prop deal.. I think i know the basics, based on what i've read over the years, but have some questions that I hope you can help me with.

First off, I understand that a 19 pitch vs a 21 pitch will be a little slower, with a few more RPM and a little quicker out of the hole.

I don't understand what the difference between "Cupped" or not is, or what the benefits/differences between a 3 blade vs. a 4 blade vs. a 5 blade prop.

Besides the rigidity what is the advantage of a stainless prop?

Here is my boat setup, help me pick the ideal prop!

1997 Crownline Bowrider 22.5ft. 350 Mag/ Bravo 1 with 300hp. I am not positive, but I think its a 1.5 gear ratio.

I have not paid much attention to RPMs Vs. Speed, but I know that I've run somewhere between 4 and 4500rpm at about 52-55mph with an aluminum 19" prop.

I mainly use the boat for watersports, and would like to have the boat plane out quickly. I don't do much high RPM/high speed cruising.

I am satisfied with the boats speed, I would just like to jump out of the water a little quicker and plane off a little quicker.

Right now as it is its a little difficult to pull a kneeboarder at 20mph because its right at that point where the boat wants to either take off or not be fully planed out.

SHould I be using a 4 Blade, 3 Blade? Stainless or ALum?

thanks alot guys

Jason
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Help with prop questions and recommendations?

Consider adding trim tabs to allow quicker planing and they also allow staying on plane at slower speeds. Cheaper than a prop.

four blade props have more blade area so moves more water, and is smoother in operation. Not generally as fast as a good three blade.

Stainless does not flex as much as aluminum so a 19P stainless performs like a 19P. A 19P aluminum probably is more like an 18P at high power settings. Hit a submerged object with a stainless prop and the prop will survive but the lower unit will not. With an aluminum the prop will be damaged but the lower unit will likely survive. Stainless = expensive Aluminum = less expensive.

What to use is best answered by visiting your dealer. They usually will let you try before you buy.
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: Help with prop questions and recommendations?

I second the opinion that in your case a set of trim tabs, maybe smart tabs would work better then a 4 blade prop.
 

lt1transam13

Recruit
Joined
Sep 9, 2007
Messages
2
Re: Help with prop questions and recommendations?

Am I right when saying that a 19 pitch prop will get the boat out of the water faster than a 21 pitch?
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Help with prop questions and recommendations?

Yes, given they are both (comparing the 19 to the 21) of the same manufacturer and design. In this case we'll assume the X dimension is the same -- I/O's are too had to change and have no "jackplate". Keep in mind there are 4 blade props that are made specifically for sterndrives.

Personally I don't buy into the theory that a ss prop tears up gearcases. If they did I sure couldn't afford to have one around here. On every one I've had (since my very first SST) the rubber hub has worked well. Just my opinion.
 

zkimball

Seaman Apprentice
Joined
Sep 2, 2007
Messages
35
Re: Help with prop questions and recommendations?

Living in Florida, we're used to skinny water. I know every shallow spot in the St Johns River between Orange Park and the Atlantic Ocean, and I'm responsible for "dredging" the half of them. I've been bottom knocking for 25 years, and have never once torn up a lower unit. Of course, we don't have ROCKS!

My father-n-law is a Merc mechanic, so I grew up with free props. SS is the way to go (if they're free!) Even if that's not the case, however, we're only talking about another $100, and you only have to buy it ONCE! The improved performance, increased speed, and fuel savings pays for the difference.

Good luck! Z
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Help with prop questions and recommendations?

http://www.iboats.com/mall/propfind...id=450&**********=341862287&*******=581743617

On a budget id go there first, it will get your rpm's up a bit and better MIDRANGE performance, not nessecarily hole shot (probalby though) If i am reading this right your looking for better performance in the lower midrange and a good 4 blade will do that over a 3 blade.

As to tab's they will get you up on plane quicker no question and you boat will have a much lighter feel, but the cost is no wake or very little wake........good for tubing you can really slide the person around back there. But not so good wake board's.
 
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