comprop

C

Chanty

New member
We were thinking of getting a Comprop for our new 22' cruiser with a Honda 90. We noticed a caveat on the company's website that said their prop may not be suitable boats over 20' in length and/or having a displacement of over 3500 pounds. Did anyone hear of this, and if you have, would you still recommend this propeller?

Warren
 
I have had this prop on my last boat, 19 starcraft, and plan in the future to put one on the Susan E. the prop allowed my old boat to plan at lower speeds , run faster at top end , and improved cornering. It also trolled smoother because of the 4 blades. really a great prop. we have posted about this in the past , so if you do a search for "comp prop" you will get a lot of info.
 
Warren-

Their warning is for motors over 225 hp/3000 lb boats. Our 90 hp outboards and easily driven hulls are easily driven with Comprops.

You'll need a 15 inch pitch prop for your combination, Comprop # M4545.

The 4 blade prop is very suitable for the CD-22 hull, with less vibration than a 3-blade. The Comprop has no rubber cushioned hub, and is designed to break blades off when hitting large solid objects, so be sure to take along a spare prop.

I've just purchased the same prop for my Yamaha 90, but haven't had a chance to try it out yet.

If you put "Comprop" in the Search engine on our Home Page, you'll find several Comprop users on this site and note their satisfaction level which is quite high!

The Comprop is available at the lowest cost from BAss Pro Shops and Cabela's. (About $79 plus shipping.)

If you're leary of the composition construction feature, Solas makes a 4-blade 15 inch pitch prop for the Honda which is aluminum, and can be had for about $108 at the following source:

Link

The 4 blade, 15 inch pitch prop in a 13 1/2 inch diameter is most commonly mentioned as being the closest to ideal for the CD-22 with 90 ho engines and normal loading and the Honda and Yamaha engines with their 2.3:1 gear ratios. The Evinrudes and Mercs can use either a 15 or even a 13 inch pitch prop at their 2:1 ratio, and the Suzuki at 2.6:1 needs a 17 inch pitch wheel. These are generalizations based on reading through many posts on both CD users sites and elsewhere.


I'll give you a report as soon as I try the new set of blades out. Joe.
 
Warren, I ran a pair of ProPulse on my twin 40s for two years with no problems. Also Bill and El have had these on their boat for at least that long. However, Pat and Patti on Daydream didn't like the fact that while doing about 10MPH (directly in front of me) they hit a 6-8" x 6ft waterloged log and stripped all four blades from one prop. They went back to metal. The prop did what it was supposed to do however. No telling what other damage coulda/woulda happened.
 
We have had some Swedish 4-blade composition propellers on our boat for about three years -- we popped off one blade on a log (like was supposed to happen) on the upper Columbia and it was easy (and inexpensive) for a friend with a good tool box (we all need such friends) to replace the single blade with our spare. We like them, and still have them (and a spare) aboard.
 
El and Bill are using a composition prop type called the ProPulse which has four individually replaceable blades and adjustable pitch. It has those two advantages as well as being very light and protecting the motor's lower end from damage like the Comprop. Try doing a Search on ProPulse and see what you find!

Another advantage of these composition propellers is their light weight. They're even a little lighter than aluminum. This shows up when shifting gears. There's a BIG difference between engaging the gears with a 3 pound composition or a 4 pound aluminum prop as opposed to a 13 lb stainless. The "CCCLLLUUUNNNKKK!!! of stainless is about 5 times as loud and abrupt with the steel wheel. If you're not shifting much, mostly just cruising around in forward gear, it might not be so significant, but for those who do a lot of trolling or close quarter maneuvering, I would think the shift dogs that actually engage the prop rotation will last a lot longer with the lighter blades. Just another aspect to consider. Joe.
 
I tried a comprop on my old 17' Arima / Honda 90. Light load, 5500 rpm the boat topped out at 30 mph. Then I tried a stainless (used Honda) 3 blade - light load, 5500 rpm, the boat reached 35 mph. I have not yet figured out how the same rpm could result in such a speed difference, unless the comprop was flexing a lot.
 
Sea Wolf said it right. The ProPulse is designed to break one or more blades if the prop hits something. This prevents $$$$ damage to the lower unit, and the individual blades can be replaced inexpensively.
Aluminum or stainless propellers bend or break if hitting an object, and if the shear pin doesn't break immediately, there can be serious and expensive damage to the lower unit.
Either way -- if you hit something, hard, you lose your propulsion -- either blades are stripped in a ProPulse prop, or blades are bent and shear pin (hopefully) pops with a metal prop. Now, the debate. Do the blades break too easily with a ProPulse prop? Lab tests demonstrate they do not -- what will break a ProPulse will seriously damage a metal prop. If this is so, and our experience using the ProPulse for years (and breaking a blade on a log) supports it, if you hit a log you can replace the relatively inexpensive ProPulse blades or take your metal prop in for reshaping.
So, like many aspects of boating, there is a choice of blade types, and each of us will favor one type over another based on our experience.
 
Thanks everyone for the input, I do have one last question on the issue. In my younger days, I remember having to replace shear pins on my outboards after hitting the bottom or an object. This was to prevent damage to the motor and/or propeller. In a modern outboard, what mechanism(s) serve this purpose? If something is built into the motor, why are so many people talking about blades breaking - I would think the motor should "give" before damage to it or the prop occurs. Again, thanks for your thoughts, Warren.
 
Warren-

Today's outboards have a rubber bushing inside the propeller hub between the propeller hub and the splined metal collar that fits over the propeller shaft of the lower unit. The rubber bushing cushions the prop and will spin and give in a hard impact, preventing damage to the internal gears, etc. The Comprop and other composition propellers instead rely on breaking off blades to reduce damage. Replaceable blades on the Pro-Pulse are about $20 each, and the entire Comprop can be replaced for $80, which is not much more than aluminum prop repair. I just paid $90 to have a stainless prop "trued" and another $45 to have it mirror polished. I don't think there's any free lunch in the "prop world", Joe.
 
Joe,

You are so right. No free lunch fer sure. I use stainless because there is so much drift coming down the rivers that composite or aluminum get trashed easily. I don't use a kicker, but the stainless always seems to get me home -- and the trip to the prop shop ain't cheap. It's been years since I twisted a shaft or broke a lower unit gear, so crossing fingers seems to help. I always carry a spare, but changing props a mon age while trying to balance on a swim step is not a favorite sport.

Dusty
 
David and Warren, if it adds any peace of mind, I contacted the designer at Comprop (Tom, 800-com-prop) and asked him the very question you posed in your original post. His answer was essentially the same as Seawolf's--that with the low horsepower and easily driven hull, the weight of a C-Dory 22 is not a problem.
 
Comprop review after 4 years of use...

I really like how this prop works for my 22' Angler. The only thing I'm wondering about is the strength integrity of these composite props. Yesterday, I broke off a blade while cruising at about 15 mph and no sign of hitting any debris. Now, I do check my prop almost every time I go out, but there might of been a small crack developing. The weird thing is almost two years ago at the Sequim gathering, the same thing happened. One blade broke off without any sign of hitting debris. The only indication you'll get is a sudden vibration. Maybe these props are only good for about two years and then they fatigue out? I e-mailed the rep at comprop about this and how the prop is used for my application. I'm real curious about what he's going to say.
 
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