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-   -   Breaking a ST Winch (http://www.sailnet.com/forums/gear-maintenance/46552-breaking-st-winch.html)

svStrive 08-29-2008 04:56 PM

Breaking a ST Winch
 
Last Wednesday while racing we had one of the winches fail. The finger/guide for the self tailer on the winch bent into the grip for the ST and actually started to peel off the grip before we stopped grinding (jib sheet). The owner of the boat talked to his maintence guy who said it may have been caused by not having enough wraps around the winch. He said you should have at least three if not four wraps on the winch to take the strain or this will happen, we had two at the time. It was blowing about 15 knts wind. I'd never heard this before. Earlier this year we had the same thing happen with the other side where the finger started to pinch in. I had thought that the metal was starting to get fatigued but, this failure was spectacular. The finger deflected a good half inch backwards and inwards. The boat is 38 years old I don't know how old the winches are. The winches are 2 speed Lewmars (don't know the model number). I find that at four wraps and sometimes three the rope tends to ride up on itself. I haven't had a problem with the rope slipping on the winch so I've just gone with two wraps on his boat and I tend to do the same on mine.
Questions
1. So should I always go with three wraps?
2. I don't see how an extra wrap would ease the strain on the finger?
3. What is the proper term for what I'm calling the finger on a ST winch?
4. Anybody else heard / had this sort of thing happen?
Thanks

sailingfool 08-29-2008 05:05 PM

When trimming by hand, you want only two wraps wraps on the winch or you increase the likelihood of an override. Put at least one more turn on or two before inserting the handle to crank. Each turn increases the friction on the winch barrel and lessens the load felt by the tail of the sheet. I have never heard of bending a "feeder arm" but I always have 3-4 wraps....if you had asked if it could happen, I'd have said "no way" the feeder arm on my 46s is pretty robust...

sailingdog 08-29-2008 06:46 PM

I've never heard of the feeder arm bending due to sheet loading... How big a boat is this and how big a winch?? I have ST40s on my boat, and can't think that my boat could possibly generate as big a load as would be required to bend the feeder arm.

svStrive 08-29-2008 07:08 PM

It's a 35 foot Ericson. Like I said I don't know the model number of the winch I'll check next Wednesday. They are about six or seven inches tall and the drum is around 3-4 inches in diameter. They don't strike me as being undersized for the boat.

sailingdog 08-29-2008 07:52 PM

It sounds like an ST30... or possibly an ST36... I doubt it's an ST40...which are the primaries on my boat. Max-on's Dehler 33 has ST 30s... so, I'd guess you've got ST36s...

KeelHaulin 08-30-2008 03:51 AM

Winches were much larger ~35 years ago than they are on production boats today. My 41' boat has Lewmar 55-ST primaries; 42-ST everywhere else. There should be an aluminum support ring beneath the chromed-bronze feeder arm. The support ring remains stationary but it's inner (circular) surface slides over the drum as the winch rotates. These should be well greased with the lewmar grease or lithium grease so it does not bind/break while under load.

I would say that 2 wraps is insufficient; the loading can be much higher at the feeder arm than you think. The jaws of the ST will hold the line much tighter than the feeder arm can withstand; so if the line slips on the drum while grinding it the load on the line at the feeder arm could be as high as the sheet load at the clew of the sail. I have seen ST heads that the feeder arms are snapped off of; for the same reason.

If you are racing and constantly trimming you should not use the ST; just have someone tailing/holding the line and preventing over-rides. I would not feel too bad about the failure unless the owner had already told you not to use the ST without a minimum of 3 or 4 wraps. On my boat the rule is to have 4-5 wraps on the primaries because the line is thin (dyneema) and the drum is tall enough to accomodate the extra wraps. The line can practically fall off of the ST head without slipping on the drum with 5 wraps.

svStrive 09-05-2008 11:20 AM

Just a final FYI the winches are 48's. I don't think they are that old. The design is newer than the ones I have on an '83 hunter. They have the spin off tops that current STs have.

h2obo 09-05-2008 11:29 AM

Check that your sheet diameter doesn't exceed the recommended size for the self-tailer. If so, the rope diameter around the self tailer exceeds the diameter around the drum, so the rope in the self tailer won't turn at the same rate as the coils on the drum and hence squeeze the arm.

jbondy 09-05-2008 01:40 PM

Another issue is the line type. I've mentioned in another post that Andersen winches do not support regatta braid. The issue isn't the guide, but the stripper that is supposed to remove the line from the top of the winch as you tighten the line. Regatta braid binds up and can damage the winch. I don't know if this is an issue for other manufacturers' products.

knothead 09-05-2008 07:16 PM

Quote:

Originally Posted by svStrive (Post 360488)
Last Wednesday while racing we had one of the winches fail. The finger/guide for the self tailer on the winch bent into the grip for the ST and actually started to peel off the grip before we stopped grinding (jib sheet). The owner of the boat talked to his maintence guy who said it may have been caused by not having enough wraps around the winch. He said you should have at least three if not four wraps on the winch to take the strain or this will happen, we had two at the time. It was blowing about 15 knts wind. I'd never heard this before. Earlier this year we had the same thing happen with the other side where the finger started to pinch in. I had thought that the metal was starting to get fatigued but, this failure was spectacular. The finger deflected a good half inch backwards and inwards. The boat is 38 years old I don't know how old the winches are. The winches are 2 speed Lewmars (don't know the model number). I find that at four wraps and sometimes three the rope tends to ride up on itself. I haven't had a problem with the rope slipping on the winch so I've just gone with two wraps on his boat and I tend to do the same on mine.
Questions
1. So should I always go with three wraps?
2. I don't see how an extra wrap would ease the strain on the finger?
3. What is the proper term for what I'm calling the finger on a ST winch?
4. Anybody else heard / had this sort of thing happen?
Thanks


From the Lewmar site:

"Remember:
Winches are designed to generate very high loads and this is stored as
energy you cannot see. Always release the load by easing off turns on the
rope drum with great care.
 Always place three or more turns of rope on to drum to ensure easy and
safe handling of winch.
 For very high loading add extra turns for safety.
"


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