Props + Pitch = confusion aka which prop to buy

wx5svr

wx5svr

New Member
May 31, 2007
112
Fort Worth, Tx
Boat Info
1995 Sea Ray 200BR
Engines
5.0 Mercruiser
After reading the archives and doing a couple searchs on google I think I have pretty much confused myself when it comes to props. Everything from what prop to buy all the way down to what pitch is best.

I have a 1995 200 BR Signature (5.0 w/ biggest cam available) with what appears to be the factory prop and it looks like the previous owner used it to learn how to boat. Either that or he drove the boat by brail. Between that and my craving for more power out of the hole its time for a new prop. I think my ideal prop would be the High 5 but I am very open to suggestions. So this brings me to a few questions:

1. Knowing my main use is for water sports what brand/line of prop to get?

2. What prop dimensions would optimize my boat for water sports?

3. Al vs. stainless steel?

4. Is there a prop that would do what I want with a smaller price tag than the High 5? I have no problem spending money for something as important as a prop but I hate spending money when there is a good alternative where you arn't paying for a popular name.

Lastly does anyone have any favorite online tutorials on props?

thanks

Graham
 
Graham

I have no opinion on the brand of prop you should buy but I can give you a few things to think about on prop pitch in general.

When a boat builder decides on what prop to install on a boat, it is based on the best overall compromise of hole shot, time to plane, top end, and fuel economy. Prop selection is also based on the power plant and the outdrive being used in a particular boat as well. For instance, on a 260DA which can be powered by three different gasoline engines, if you have a 350MAG or the 6.2 liter motor, the gearset in the outdrive is 2:20 to 1 and the prop is a 20p. But if you have a 496MAG, the gearset is a 2:00 to 1 and the prop pitch is a 22p. Now generally speaking the lower the pitch, the faster the hole shot and the faster the boat will plane off. But if you go too low, you run the risk of raising your RPM too high for general cruising and you will burn more fuel plus your top end will usually be diminshed as well. And, depending on how low you go with the pitch, the motor may be "bouncing" off the rev-limiter as well at top end. When Sea Ray built your boat, all those things were tested by them to provide the best combination for your motor and outdrive. In fact, they even have a recommended prop for "high altitude" where the performance of the motor itself will be affected. Now in some cases folks are willing to put up with some compromises to gain things like a better hole shot or a higher top end. The better hole shot is certainly acheivable with a lower pitch prop but you will usually have a lower top end and higher cruising RPMs. If one were to select a higher pitch prop to increase their top end, then their boat may have difficulty planing and it still may not be able to acheive the higher top end if the engine is not powerfull enough to to run at max RPMs.

If you stick with the same pitch but take advantage of newer technology in props, sometimes the newer designs can deliver improvements accross the board in how your boat performs. Or sometimes these manuifacturers will have recommendations on switching to a different pitch too based on their own testing results. Maybe someone else on the board can give some recommendations in that regard. Just keep in mind what works well on one model boat may not work so well on a different model.

Dave
 
The 5.0 engine is nicely matched with a 20 ft boat. But realize there are a lot engines bigger than this. So many prop choices are out of your reach, just like bigger engines. I wouldn't guess that prop as a first choice - you just don't have that much power. You're going in the right direction spending your money on a good prop. That is, so to speak, the low lying fruit of performance. And I would definitely invest in a stainless prop. The Vengence is a popular model, for good reason. The Mirage is even better, but may turn out to be more prop than your engine can use. If you can try a good prop - even aluminum - you will have some information to work from. Try moving from there. But of course, you should have your engine running at peak performance before doing anything with a prop.
Good luck.
 
I guess I'd start at the beginning. First of all, with what is left of the prop are you hitting the WOT as suggested by the manufacturer? I'm guessing it's probably 4600 to 4800 for the 5.0, but I don't have a clue. If you are hitting that mark, then the prop is a good match. You can alter that somewhat, but you will give something else up in return. In other words if the current prop is a 14 x 20 and you want more hole shot, try a 14 x 18. It will get you up faster, but you will lose some top end speed. There are fancy props out there that may help you stay on plane at a slower speed like a 4 blade. Again, I have no experience with these, just what the ads claim. I think if you had your current prop refurbished by a prop shop it would make a difference. Then use that as a basis to make the changes you need. If you always carry a boat load full of people, less pitch might be good. If you run the boat empty and are bass fishing for example, high speed and a higher pitch might be in order. No matter what you do, keep the current prop as a spare and see what the dealer will let you try out. I think some of the props are more of a marking gimmick, but again, no experience there!
 
Thanks for the replies guys. I have been extremely busy and will re-read these posts and follow the links this evening. Likely resulting in more questions.

Thanks again for the help.

Graham
 
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