prop change from 14.5 to 14.25?

I have a volvo 5.0 and penta sx-m 1.5 with a 14.5X19 and have a spare 14.25X19 that is a SS prop instead of alum. Would this be a bad change in losing hte .25 in diameter - or will this really make any kind of difference? I have switched from the original 14.5X19 alum to a 14.5X18 4 blade alum, and really don't feel that I like the way it changed...

Thanks,
Brian

Re: prop change from 14.5 to 14.25?

Generally the diameter has little or no affect.In the extreme it mightchange rpm 50 or so.
Changing to a ss will likely have some very noticeable changes.
A 4 blade should improve hole shot,stay on plane with less throttle.run smoother and handle
better at speed and at the dock.You will likely lose some top end.How did yours do?

Re: prop change from 14.5 to 14.25?

I wish I had paid more attention to the before and afters, but I had the standard volvo 3 blade 14.5X19 and was not so much not happy with performance, but seemed to spend a bit of time on and off plane, so I switched to a 4 blade 14.5 X 18 prop and I think it may plane faster, but my rpm's seem to be a bit higher most the time as well. I have another prop on a boat I am selling with a 14.25X19 SS, and am thinking about trying it out, but did not know about the smaller diameter part, and how much affect that would have. I think I will write down some stats with the 4 blade, then switch to the SS 3 blade and see which one is better.

Thanks,
Brian

Re: prop change from 14.5 to 14.25?

Hi Brian,

Hate to state this, but you should look in the stickies at the top of this prop forum page... specifically, the "Read this first".

As Steel says, you will probably not notice any change in rpm between the .25" dia difference. You should see the performance change that SS will bring to the table. Since it is usually thinner yet stronger, there is less flex as it pushes through the water. This will tend to give a better hole-shot as it digs, and thus usually better top speed. However, this better efficiency means less slip and thus lower rpm is typically seen.

A different sticky describes test results between several prop manufacturers. You may want to study this to gear up on possible changes in performance. There are many factors (potential differences) when comparing AL to SS. Some AL work very good on one set up and some SS can work pretty bad. It isn't always a direct assumption the SS will be better in all cases.

Give the SS a try, but please write down the performance specs before and after the change. Also provide the manufacturers and models of each.

Thanks and good luck!