Trac 16 Mast Sheave :: Catamaran Sailboats at TheBeachcats.com

Trac 16 Mast Sheave

SquamCat

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Posted: Sep 11, 2009 - 07:12 AM

My Trac 16's mast sheave melts from friction until the ball bearings fall out. I am using a Harken self contained sheave (H160) and have tried spraying the mast track with sail kote. The sheave starts to fall apart after raising the sail a few times. Is there a more durable sheave with 1 1/8" diameter? My halyard is 1/4" sta-set poly braid and is pretty new. Any ideas would be appreciated!
MN3

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Posted: Sep 11, 2009 - 09:03 AM

i would try a thinner halyard... as long as you wear gloves.. you can go pretty small...
Wolfman

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Posted: Sep 11, 2009 - 12:40 PM

First, I know nothing about the Trac 16 specifically, but I know some about sheaves/pulleys/bearings.

Are they melting from friction from the halyard or in the bearing itself? (i.e. is the outside of the sheave melting until the center falls out, is the outside heating up causing the whole sheave to distort allowing the bearing to fall out or is the sheave melting around the bearing itself).

If it is the first two cases using a thinner halyard rope and spraying it with a silicon/teflon lubricant (any silicon spray will do) may help.

If you are melting from the bearing side then there is too much friction within the bearing or between the bearing and the pin holding it. In that case try some lithium grease on the sheave pin and or repack the bearings (if it isn't sealed) on a new sheave with some lithium grease and that may help. You can also try a non-ball bearing sheave just running on the greased sheave pin (although this could even make the problem worse but is worth a try if all else fails).

D.

--
Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
--
SquamCat

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Posted: Sep 11, 2009 - 07:45 PM

Thanks for the responses. Yea, the sheave is melting from the outside from the rope friction. I recently replaced the sheave and it worked great for two sails. The third time out there was some wind on the sail as I raised it, causing more resistance, and when I lowered the sail it came down roughly. Each time I have sailed since, I see little pieces of plastic on the end of the halyard.

So, should I use a 3/16" halyard and spray the halyard with silicone? I sprayed the mast track and sheave with Sail Kote to make the sail go up smoother, but haven't sprayed the halyard itself. Thanks again!

Eric
Wolfman

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Posted: Sep 11, 2009 - 10:25 PM

Wow, that's a lot of friction! There shouldn't really be any if the sheave is spinning properly on the bearings.
It sounds like you must have something more than rope friction going on there. The sheave should only move when you are raising the sail (roughly 30 feet) and other than that should just sit there. That isn`t enough use to cause a sheave to break apart after a couple of sails.

Are you bolting them on (mine are just pinned)? If so are you torking to bolts down too much and not using a self locking nut? Is there any binding happening in the top casting (you will see marks)? If things are binding, a little tuning with a mill file might help.

You could try a Ronstan sheave. The Ronston sheave has no bearing and is made out of a plastic, they call it acetol but it is really similar to Delrin or UMHW (used in all sorts of bearings). Grease the crap out of the pins or bolts (whatever goes through the hole of the sheave) and spray your halyard with the sailkote.

--
Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
--
Wolfman

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Posted: Sep 11, 2009 - 10:26 PM

Wow, i didn't realize the forum blocked out bad language! No wonder everyone talks so nice. :)

edited by: Wolfman, Sep 11, 2009 - 09:26 PM

--
Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
--
MN3

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Posted: Sep 12, 2009 - 12:37 PM

i also don't know the trac at all but...
is this the block at the top or bottom of the mast? if it is the bottom... i would bet the farm that the block is twisted and creating the friction. i had the same problem in several locations (spin tack and main halyard).

the solution was to make sure it can swivel regardless of the angle you are pulling (almost impossible to pull straight ...

you stated that wind added friction... you should be pointing directly into the wind and there should be little added resistance from the wind.

another possible solution is to have someone help feed the sail... pull slower and reduce friction.

also.. if you simply spray lube in the track... it will coat the back of the sail track (the bolt rope doesnt touch that area so you are not lubing the track) i always use a soft cloth and dip it (or liberally spray) the cloth and use a dowel or pencil piece to hold it in the slot and work it all the way up and down the track several times.. removing and re-coating it (when the mast is down)

lastly.. you can also lube up the sail bolt rope itself

please keep us posted...
SquamCat

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Posted: Sep 12, 2009 - 01:11 PM

It is the sheave at the top of the mast. I will flip the boat over and inspect the mast where the sheave is connected by a pin and file down the mast if needed. I will also spray sailkote on the pin, sheave, track, and halyard. Hope this works! I will also order a new halyard - do you think 3/16" is the best size?

The sail has lots of camber from the battens, so perhaps that adds to the friction. I always head the boat into the wind when raising the sail, but sometimes the wind shifts in my cove and it makes it more difficult to raise the sail.

Thanks, Eric
MN3

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Posted: Sep 12, 2009 - 01:17 PM

yes, everytime i start to raise the mast the wind shifts.... thanks murphy!

if you really want to soften your halyard you should soak it in Holmoken (look it up)
CrdStang

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Posted: Sep 13, 2009 - 03:35 AM

Go to a hardware store and find some stainless steel sliding patio door rollers. I paid $20 for a pair.
MN3

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Posted: Sep 13, 2009 - 11:56 AM

and do what with these patio door rollers?
CrdStang

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Posted: Sep 13, 2009 - 03:48 PM

It might be more obvious once you take a look at them.

http://smg.photobucket.co…=view&current=sheave.jpg
Wolfman

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Posted: Sep 13, 2009 - 07:53 PM

Regardess of what sheave you use, I would use a heavy grease (any type would do, you can pick up a small tube for a couple of bucks at any hardware store)on the pins and the bearing hole of the sheave. Sailkote is a good lubricant for fabric and rope but will do next to nothing on rolling bearing, it will wear through almost immediately in that location. The grease will reduce friction and stay on the bearing surface, even if you dump the boat in the water.

Oh and if you can find a bronze or stainless sheave that may help also, but I would grease the sides of the sheave. The plastic they use for the sailing sheaves has the property called 'lubricity' meaning they are slippery therefore they are somewhat self lubricating. Bronze has this property to to some extent, but stainless causes a lot of friction when it rubs against another metal.

edited by: Wolfman, Sep 13, 2009 - 06:57 PM

--
Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
--
SquamCat

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Registered: Sep 10, 2009

Last visit: Sep 17, 2021

Posts: 49
Posted: Sep 13, 2009 - 08:15 PM

Thanks! I have some lithium grease and will give that a try. We've had nice wind in New Hampshire so far this September - happy sailing!
SquamCat

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Posted: Sep 22, 2009 - 09:36 AM

So I took a closer look at the top of my mast and the sheave has very little clearance from the mast itself. When the halyard is under pressure, the sheave is rubbing on the metal and that cause the sheave to fall apart. I tried to file the metal down, but I think I need to drill out three rivets and take the mast head off to get access to the top of the mast, or maybe I can get in there with a dremmel grinding tool. The Harken sheave is 1 1/8" diameter - is there a 1" diameter sheave available?
SC19

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Posted: Dec 22, 2023 - 04:30 PM

I'm fastidious