Transmission issues

Apr 19, 2016
9
Catalina 30 Alameda, CA
Hi all,
I have a 1984 Catalina 30 with a um-25 and hurth hbw-50 transmission. Yesterday I was sailing under power. I noticed eventually that my speed had dropped severely and there was smoke from the transmission.

I let it sit for awhile, removed a cable that burned up because it was laying against the shaft, and re-started the engine. This time I was able to get back to normal speed for about 20 minutes (heading home, no wind) before it began to smoke again. I realized that the shaft was rotating much slower than normal.

I decided to bypass the shift cable and operate the shifter arm manually. After this I was never able to get the shaft to rotate fast enough in the forward direction. I was however, able to operate the boat as normal in reverse. I reversed for another 20 minutes and made it safely to my slip.

This morning I woke up and tested the transmission again. This time, no matter what gear the boat is in, the shaft does not turn at all. I haven't yet tried turning the shaft by hand.

Any thoughts? I'm dreading the prospect of replacing the entire transmission.
 

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Mar 10, 2015
62
Catalina 30 Moss Landing, CA
Was the prop shaft hot enough to burn the cable "laying against the shaft", or could it just have been friction? Which cable, BTW? And did you check the tranny fluid level?

This sounds like a line wrap around the prop with possible seizing on the strut or elsewhere to me. The first obvious thing is to see if the shaft rotates freely both ways in neutral, and even if it does, go down and check the prop and strut visually for evidence of a line wrap. This may have freed up in reverse, but causing burning out of the clutch plates by trying to proceed on in FWD under normal power again. Big mistake to do this with an undiagnosed obvious problem somewhere in the drive train severe enough to burn something inside. Best to shut down and call for a tow if sailing in won't work.

Just for interest regarding a recent thread, do you sail with transmission in N for free shaft rotation or lock it in FWD or REV?
Pete
 
Apr 19, 2016
9
Catalina 30 Alameda, CA
It was the throttle control cable. It didn't wrap around, it was a friction burn. The throttle cable itself worked fine, even after it was damaged. I always sail with the throttle in neutral, although I didn't realize how big of a deal it was to not have it in forward until I saw the most recent post. Will check to see if it turns freely tomorrow. Tranny fluid was good.
 
Mar 10, 2015
62
Catalina 30 Moss Landing, CA
It was the throttle control cable. It didn't wrap around, it was a friction burn. The throttle cable itself worked fine, even after it was damaged. I always sail with the throttle in neutral, although I didn't realize how big of a deal it was to not have it in forward until I saw the most recent post. Will check to see if it turns freely tomorrow. Tranny fluid was good.
Just to clarify things, the "wrap around" I was referring to was a line wrap around the prop with secondary binding of the shaft, which still seems the most likely suspect for the cascade of transmission problems, resulting in a burnout of the clutch plates.
Pete
 
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Apr 19, 2016
9
Catalina 30 Alameda, CA
Ah I see what you mean. I dove under and found that the prop was free and clear. But it's possible I had a line wrap that later freed itself after doing all of that damage. I just find it quite a coincidence that this happened the first time I ran it after replacing the shutoff cable and not zip tying everything perfectly back in place
 
Mar 10, 2015
62
Catalina 30 Moss Landing, CA
Usually a line wrap stops the engine dead, as the source is most often a secured line from your boat - eg the dingy painter not shortened up when backing down, an errant genny sheet or dock line. But I can see how an unsecured line could bind up the shaft but still allow some turning, with great stress on the tranny's clutch plates or cone. Does the shaft turn freely now in N, with no abnormal sounds, etc? And trying to turn it in FWD or REV, any resistance or grinding noises?

My last experience was hitting a bouyed but unlit 3/4" very long fish net line in the middle of the night approaching Panama City, Panama in '99, powering our 37' catamaran dead to windward. Suddenly both engines stopped, the cat pitched bow down, then rebounded back and swung around stern to wind. It took about 45 minutes each side with mask and snorkel to saw away the bar-tight partially melted polypropylene line from the Yanmar saildrives under the pitching hulls, my wife shining a big spot down from above. She was freaked out about sharks the whole time, but thankfully that possibility never entered my otherwise occupied mind!
Pete
 
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Apr 19, 2016
9
Catalina 30 Alameda, CA
Sounds like quite an adventure! So the shaft turns freely in neutral. It also turns freely in forward and reverse. I don't believe that the clutch lever was actually shifting gears though. I also found metal shards in my transmission fluid.
 
Mar 10, 2015
62
Catalina 30 Moss Landing, CA
Sounds like surgical intervention time, and hopefully not an autopsy. If it is the clutch plates destroyed shifting probably wouldn't make any difference you could feel, vs destroyed gear/s or bearings with intact clutch.

Good luck, and please let us know the outcome of this very curious problem.

Pete
 
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Apr 19, 2016
9
Catalina 30 Alameda, CA
Will do. I plan to take the Transmission off this weekend and have a look. I'm expecting to have to replace the whole thing, but maybe I'll get lucky
 

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