Busted Comprop

[drbridge]

Well we took the Susan Marie to lake Crescent for it's end of season bath/Cruise. It was a great day for October so we took two of our grandson with us. we went all the way around the lake at different speeds and opened it up a few times, but mostly 10 to 16 kts. after we turned around at the west end of the lake I opened it up to 18 kts and headed back for storm king. About 1/3 of the way back the motor started shaking violently and I her shut it down right away. When I raised it up one of the 4 blades was busted off of the comprop. We were cruising in perfectly clear water about 400' deep and I had my eyes on the water when it happened. I do not think we hit anything.
On the way down there on the other side of the lake there was some woody debris floating on the surface. I did hear a small tink, tink on the bottom of the boat at 12 knts but it was a very small stick and I did not feel it hit he prop. I wanted to run the kicker out anyways, so we used that to take a slow cruise back to the dock. I then put the Standard 3 blade prop on and went back out for another spin. To me this prop felt smoother than the comprop. top speed was .5 kts higher topped out at an identical 5400 rpm. To me it felt like the three blade was coming out of the hole faster also. The Comprop would rev out faster out of the hole but I don't think the boat was moving as fast as it did with the standerd three blade.
ten years ago there was some threads on this subject and there were a number of opinions including Bill (PO) who thought that just the opposite was true and thought very highly of this prop. I am wondering ten years later what the track record has been for these props and how well they are thought of by those that use them.
This prop had no more than 140 hours on it. I am still not sure why it broke. I did some research and some said that the composite props will break off a blade if you hit a small stick. perhaps I did hit the previously mentioned stick and put a small crack in it that later opened up and severed the blade. School of thought by some that if you hit a log and break off all the blades it is better than taking out the whole lower end. If I am in the middle of the strait of Juan De Fuca and I hit a small chunk of wood in rough water an aluminum prop would be OK. if the comprop breaks a blade it is unusable. on a flat lake Crescent I did not mind climbing out on the swim step to switch out the prop. I don't know if I would like that very much in the middle of the strait in rough weather. It could be a problem. I am wondering if these props ever come a part from fatigue or only if you strike an object.
Let me know your experiences (Good or Bad) with these props ten years later.

Thanks, Doug

[Robert H. Wilkinson]

I have looked at these props. When I switched to a 4 blade this spring I asked the service manager at my marina about them. I thought they might be good in case I needed to make a pitch change(I dropped 2" going to a 4 blade). He did not recommend a comp. prop. I ended up getting a Hustler 2 piece prop. I am quite happy with it. Because of their "squeeze cast" process Hustler claims "Stainless performance at Aluminum prices". And the aluminum will still offer impact absorbing to protect the lower gearcase. Depending of coarse on the severity of the impact - an aluminum prop will usually get you home in a pinch if it is not too badly unbalanced and you keep the rpms low.

Regards, Rob

[Hunkydory]

I went to the pro pulse comp props due to the combination of being able to change pitch & tired of bent blades on the aluminum. I read all about others complaints of these props losing blades at the slightest small hit or not hitting anything at all, but thought their problem was more related to the higher hp motors than our twin 40's. Then following four different Alaska cruises & many thousands of miles with them, I too became tired of replacing blades after hitting small chunks of ice & very small pieces of wood in Alaska that wouldn't have even bent the blades on a aluminum prop. Finally three years ago I changed to a three bladed stainless prop that have since been totally trouble free. With this much reduction in prop problems, I'll take my chances with the possible increase of lower unit damage if striking something really hard.

Jay

[hardee]

Doug,

My boat came with ProPulse (composite) props on the twin 40 Yamaha's. They worked fine as far as I knew, for about 3 years, then within a month, I lost 2 blades off one side and then a single on the other. No hits, but some sort of filament that did not look like fish line was tangled in one. On the other, nothing.

I spent way tooo much time looking for replacements for the ProPulse blades, (#6502) and finally went to twin, 3 blade aluminum with the help of Matt at Kitsap Marine. They ran better, smoother and fit the WOT bracket better.

I still carry one ProPulse as a spare, but it will be the last. I could not find replacement parts for the hub or fins for my size. Info from several prop places, they were not importing my size anymore.

Harvey
SleepyC

[journey on]

Journey On lost a couple of blades on one of those plastic props, just off of Dent Isle, north of Yaculta Rapids. Just went through some seaweed. Lost 2 blades, went to the backup engine.

Got into a marina back of Dent Isle on the Honda 10, replaced the blades, got home and changed to a stainless prop. No more problems with lost blades. The stainless even got chewed up on some rocks (stupidity) but kept its blades.

I've posted my opinion on those plastic props for years. I'm surprised anyone is running them.

Boris

[jimandlaurie]

We did the Pro-Pulse thing for a while til the Blades started breaking. got to be pricey and time and effort consuming so went back to a stainless prop and never looked back.

[Sunbeam]

I have aluminum props but I wonder about the idea that a stainless prop that hits something is (more) likely to damage the lower unit. Is this true? Or aren't there already breakaway type protections on the engine?

[journey on]

sunbeam,

All props have something in the hub that shears or slips if the prop hits something. For example, the Michigan Wheel stainless prop has a plastic insert that gives up the ghost when the prop hits something, hard. The Honda aluminum has a rubber insert that does the same thing. The blades stay intact and so does the motor.

With the 150 HP motor on Journey On, we went through both inserts when I found out how much fun it is to jam the throttle wide open. Prop and water inertia played hell with those inserts. The prop repair guy said not to do that. And both props got us home, albeit at a low speed. I can only imagine what 200 HP would do.

Your pick as to what prop you run.

Boris

[Sunbeam]

Okay, so my question is do the rubber (or etc.) hubs or shear devices not work well enough with stainless props? I often read that one is risking damage by running one, is why I ask. (Yet I would have presumed that the protection would work with any prop... maybe I would have been wrong?)

I have aluminum props and am happy with them, but I would still like to know as I might change some day. Plus, I just want to know.

[thataway]

Spun hubs can happen with just overload, on both SS and Aluminum props, as Boris noted. I had 12 people in a 20 foot GW, and hit the throttle hard--spun the hub. I have never worried about a lower unit being damaged by a SS prop vs. Aluminum prop. The only time I busted a lower unit, was when I hit an uncharted pinnacle rock in AK with a 25 hp on the RIB--The aluminum prop also took a hit. It would not have made any difference if the prop was aluminum or SS--the gear case would have gone.

There are some props which do not have hubs which will not slip.

[drbridge]

Ok, so it seems there are a number of negative reviews and none positive for the composite props. My own gut feeling is that I don't think I want to run this type of prop. I will stick to the aluminum model. I am not going to race this boat and it is already one of the most economical in its class, so I don't think I need the perfomance of SS, If the aluminum props wear out fast it is very affordable to replace once a year for $100 a pop.
Thanks for all the input

Doug

[Da Nag]