Twin 40's Prop Question.

B

bcassal

New member
I'd like to ask the C-Brats running twin 40 hp. motors on the 22 cruiser what pitch props they are using and what prop experience and advise they may have to offer.
Carpy has twin Honda 40's and currently has 11 1/8 x 13 stainless props. My WOT is about 5200 rpm. I run both Permatrims and trim tabs and we are generally heavily loaded. I'm thinking of dropping down to 11x11 props.
Rather than spend around $500 on new props, I can have my current props rep itched for $65 each.
I'm hoping to get my WOT closer to the 5500-6000 rpm recommended by honda.

I look forward to your comments.

Bruce Cassal
Carpy
 
I don't have specific prop numbers for you, but but if you are 5200 at wot, you definitely need to go down. Re-pitching works if the outfit doing it is any good. So for 65 bucks each, you need to drop at least 1.

Personally I'd rather be some under pitched than over. Lugging these engines is not a good thing.
 
Bruce, we'er now running New Solas stainless 12"x10p on our Honda 40's & also have Permitrims & trim tabs. Depending on weight & altitude wot rpm varies between 5300 & 6000 rpm with top speed approximately 18 to 24 mph. On our Southeast Alaska extended cruises with topped off fuel being 101 gal, Wallas fuel 6.5 gal, water 25 gal & all the other extended cruise items we are extremely heavy & also tow a Mokai, so this prop is the perfect match for us. I think for you perhaps the 11 pitch would be better. Honda recommended wot throttle range for the 40 hp is 5000 to 6000 & the 50 hp is 5500 to 6000 so the 11 pitch should put you right in the middle or to the upper end & give a bit more cruising & wot speed then us.

Jay
 
I've got twin Honda 40's on a heavily loaded (not as heavy as Hunkydory) CD22. With 10.8dx12px4blades Solas aluminum props I ran wot at 5400 rpm, 27 smph, and 4.5 smpg. Switched to 11.1x11x4 Solas aluminum and ran wot at 6000 rpm, 26 smph, and 4.3 smpg. Both props with trim tabs and permatrims. I like the 4 blades and run around lots of rocks, hence aluminum; on the web each prop is only about $125 (or was 3 years ago). When switching from 3 bladed to 4 bladed I first dropped an inch but eventually 2" got me where I wanted to be because when I really load up at times, wot drops to 5300 or 5200 rpm (with the 10.8x12 it went to 4600- too low).

Jay
 
Take a look at Piranha propellers. Each blade is individually replaceable. I haven't bought any recently, but the last time I did, each blade cost about $17. Blades are easily replaced, and it only takes a few minutes. I think they give me more thrust because they're hydrodynamically shaped better, but that's just my opinion. When you do hit something, you lose only a relatively inexpensive blade rather than the whole prop and possibly drive train, since steel props propagate the impact energy much more so than the synthetic blades do. Other than being a fan, I'm not in any way affiliated with the Piranha company.
 
Thanks all, for your comments.

It seems that my best course of action is to have my current props repitched to
11x11. I have used Prop MD( http://www.propmd.com/propeller-pitch-change.html ) for prop repair and have been very pleased with their work. I carry the 11x13 aluminum props that came with the boat. So I don't need spares and don't want to spend more than I need to.
I have long ago given up on aluminum props. When I had them on other boats I usually had 2 in the shop for every one a boat. I have a tendency to go to where I can, more than where I maybe should and I have had excellent service from stainless.

Smitty, I talked with you about the Piranah Props when we were at the first Mississippi gathering at Gutenberg in 2010 or 2011. They are an intriguing concept. I like the way they can be altered and repaired. It might be a bit of a new trick for this old dog though. A multiple piece composite system seems problematic to me, although I know you have used them for years, Has anyone else had experience with these props ?

Bruce
 
We used the 4 blade, pitch adjustable, Propulse composite, blade replaceable props for at least 5 years & also sang their praises, but after replacing many blades from minor contact with small ice bits & pieces of wood changed over to stainless. We had also used a four blade non pitch adjustable composite & aluminum 3 blade before the replaceable 4 blade composite. The stainless improved performance & prop longevity over all the others used previous to them. We'er also inclined to spend a considerable amount of our cruising time in skinny water exploring close to shore & still consider the positives out way the negatives with stainless props.

Jay
 
My experience with the composite props (ProPulse to be specific) was less than satisfactory. They were OK until they broke, then could not get replacement blades, or the right sized replacement hubs. Is short, I have one prop left as a spare, that is made up from three originals.

I have been very satisfied with the aluminum replacements. No problems in the last 4 years.

Harvey
SleepyC :moon

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I've got 2001 Honda 40s with aluminum Honda 3 blade props stamped 11.4 x 12 HQ. She tops out at just over 28 mph at exactly 6000 rpm with a medium load at sea level.
 
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