C-Dory 25 prop decision

thataway · Posted: Sat Apr 24, 2010 5:29 pm Post subject:

What is your cruising speed and RPM--you may actually be better off going down to 11" and keeping a 15 5/8" prop in SS. (That was what was advised for my 130 by Prop Gods--and ended up being down by the new owner (on Powell)--and dramatically increased the speed there--I suspect it would also increase the economy if you are lugging the engine--which is quite possible, since you are not turning up full RPM at WOT. You want to keep as much blade surface area because of the load--and even going to 4 blades might be a consideration--giving more lift to get on a plane faster.

breausaw · Posted: Sun Aug 26, 2012 10:41 pm Post subject:

Instead of creating a new thread I jump in here.

Our new to us 25CD has a Mercury 150 Verado; Max RPM at WOT should be 5800 to 6400. The boat came with a Mercury 3 blade 19 pitch stainless prop; I was only able to get 5500 rpm. I called my local prop shop and settled on trying a 14.25in 17 pitch 4 blade stainless Solas, could only make 5250 rpm. Although I didn’t get the RPM I was hoping for the 4 blade picked the stern up and fuel economy improved. Next prop we tried was a 14.5in 15 pitch 4 blade stainless Solas, max RPM about 5500, even better fuel economy.

So now I’m thinking of just going to a 13 pitch 4 blade, I don’t think dropping one pitch is going to get me into the RPM Range I’d like.

Is anyone else running a 150hp Merc Verado?

bcarli · Posted: Mon Aug 27, 2012 1:35 am Post subject:

My c-dory 25 with a 135 honda came with a three bladed stainless 141/2 x 15 prop. I used that prop for a few years putting about 600 hours on it before trying a 151/2 by 13 aluminum three blade prop. I have put about 1400 hours on the new prop. Last week I hit a dead head and had to put the older stainless prop on and boy what a difference. The 151/2by 13 drives my boat SO much better. I get much better fuel economy, get much better boat speed at lower rpm's and get up on a plane easier and quicker with the aluminum prop. The difference between the two props was amazing. I carry a heavy load on board ( average 6 to 7 people) and that may influence my prop size. I'm wondering about going to a 16 by 13 as there is about a 1/16 of an inch clearance using the 16 x 13 prop....
Just my experience
Bill.