Prop type i should have

[ldirubbo]

I have a 2004 350 and two different props. The boat currently has a 14 in prop but when I bought the boat the owner said that the original boat came with a 15 in prop which is in my storage compartment but it wasn't very good so they sent out new 14 in props. Reading the other posts I am trying to figure out which prop is the correct prop to have. Can anyone help?

[leigh weiss]

Congratulations on a fine selection for a cruising boat.
If you follow the posts about the prop you will get some insight into which is best for you.
Several people have used folding or feathering props and tried other sizes and pitch looking for the optimum of low noise and boat speed under power.
Catalina had a prop replacement deal for some time in the past this may be why you have two props. I settled for a feathering prop (Kiwi) to gain reduced drag whilst sailing and provide quiet forward operation. (no cavitation noise) .
Let us know how you make out.

Regards,

Leigh Weiss Brisa #155 Northern Chesapeake Bay

[ldirubbo]

Leigh,
Thank you for the information. I will look at the previous posts and figure it out.

[wolfe10]

Three variables:

Diameter
Pitch
and, the unusual one-- distance behind that large skeg that produces turbulence around the prop.

So, the basics:

Does your prop cavitate (that "boiling water" sound)?

If not, is it the proper "in a vehicle= rear axle ratio". With transmission in neutral, what is max tach reading? With engine in gear, smooth water, clean hull, what is max tach reading? Should be within 150 RPM or so of "in neutral" reading.

If in gear, the tach immediately goes to max RPM, the prop is too small (diameter and/or pitch). If in gear the tach is more than 150 RPM from "in neutral" speed, the diameter/pitch is too much.

Brett

[belladonna]

ldirubbo - First I'm sure this is not your name but will use it!!! Did you ever find an answer from reviewing the posts as to which prop is better for the 350; the factory equipped 15R9 or the follow-on 14R10?? Most of the posts reflect on folding props and I never got a clear idea of which of the two mentioned props were best. I read the article by Gerry Douglas from 2006 but even that didn't give me a clear-cut solution. However I have the 15R9 on my 2005 350 and Catalina wants $395 + shipping for the 14R10 and I'm not sure that the money is worth spending. Can anyone else provide me with any quidance as it would be greatly appreciated?? Jim Lassiter BELLA DONNA # 368 Deltaville, VA - lower Chesapeake Bay.

[russp]

Hi Jim,
I don't have an answer for you, except I went down the same path, spoke to Warren Pandy and read all the articles. As far as I can tell, if you switch to the 14x10 you will get less (but possibly still some cavitation) and more drag than the 15x9. Both are a compromise between motoring performance and minimising drag.
In the end I decided if I was spending on order of $500 for a fixed prop I was better off staying with what I had (15x9) or jumping to a feathering prop, which I have done. I spent A$2000 buying a Kiwi prop and there are several articles on the forum talking about them. With the Kiwi you can have a much more powerful prop for motoring, but still with minimal drag when sailing and I have noticed the extra speed when sailing already. I can now motor in flat water at 6.8 knots at 2400 rpm (WOT) and with a little bit of pitch adjustment it should go even faster if needed.
It is a more expensive, higher maintenance (but not really onerous) proposition, and very easy to fit. The only thing I don't like is that it "thunks" when you select reverse and I am hesitant about how it is going to bash the gearbox if I have to jump back and forth quickly between forward and reverse if manoeuvring in tight quarters.
Hope this helps, I couldn't find any definitive answer, at some point you just have to take a punt.

Russ Peel
Avalon #150

[KenKrawford]

ldirubbo, I changed from the 15x9 to the recommended 14x10 prop 3 or 4 years ago. My issues with cavitation are gone for the most part. I've started to notice a slight amount of cavitation occasionally but it's been 2 1/2 yrs since I had a bottom job and Gerry Douglas swears that bottom growth contributes to cavitation.
If you're not having any cavitation issues, I'd just leave well enough alone. If you are, then you can switch to the 15" prop but I'd be amazed if it decreased cavitation.

[ldirubbo]

Hi,

Thanks to all of you for your comments. I do have the 14" prop on my boat Mandy but wanted to be sure it was the right one since I also have the 15' prop in my storage locker. I do get some cavitation at times but I think this is due more to increasing the RPMs when I am trying to fight a bad current coming in different directions.

Eventually I will look at other prop types and see if there is a big difference in performance. Reading the posts about folding props and all, I am not certain it makes that great of a difference for my needs. It is similar to when my son and I sail. He is a racer and I am a cruiser. My son is constantly trimming our sails to squeeze out a 1/4 to a half nm more in speed. Me, I would rather relax and enjoy the sail even if it takes me a little bit longer to get there.

[marklunorman]

Hi all
I've sailed #143 out of Baltimore for almost 4 years. PO never took Catalina up on prop exchange so I had 15x9 and cavitation issues. At last years haul out I replaced cutlass and while I had the time, repitched the prop. Local shop made it a 14x10 for $180 which was far better than purchasing a new one.
I'm very happy-cavitation is gone. I may have more speed and less power but its not really noticeable. Bigger issue in mid-6chesapeake is keeping the barnacles off which I haven't solved yet.
If the kitty was bigger I have a folder but this was a good fix.
Mark