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A-cat - Luff track problem #106076
05/06/07 09:15 PM
05/06/07 09:15 PM
Joined: Oct 2003
Posts: 118
St. Louis, MO
JoeLeonard Offline OP
member
JoeLeonard  Offline OP
member

Joined: Oct 2003
Posts: 118
St. Louis, MO
Problem...certain I'm not the first...looking for the best solution:
Boat - Boyer/Auscat Mark V
Mast - Applied Composites
Sails - two different sails - same problem
Problem - while sailing the bolt rope starts to pull out of the mast...starting at the bottom, just above the entry slot and then slowly working up the mast / luff.

I'm looking for solid advice from others who have seen or experienced the same thing.

Thanks!!


JL N20 # 1041 "Lucille" A-cat USA 44
-- Have You Seen This? --
Re: A-cat - Luff track problem [Re: JoeLeonard] #106077
05/06/07 09:28 PM
05/06/07 09:28 PM
Joined: Feb 2006
Posts: 19
U
USA197 Offline
stranger
USA197  Offline
stranger
U

Joined: Feb 2006
Posts: 19
Assuming there is nothing wrong with your sail or mast, this can happen when you tighten the outhaul before the downhaul. If you set the outhaul to about the right tension, especially in heavy wind, then tighten the downhaul, the bottom of the sail will pop out. The geometry causes the tension on the foot of the sail to increase as you increase downhaul pressure. To avoid this problem you should downhaul first and then bring in the outhaul. In heavy air you won't be able to get the downhaul in tight enough from the tramp on the trip downwind, so you will have to leave a little extra slack in the outhaul knowing that the final application of dowhnaul will pull the foot tight.

Eric

Re: A-cat - Luff track problem [Re: USA197] #106078
05/06/07 09:49 PM
05/06/07 09:49 PM
Joined: Aug 2005
Posts: 2,921
Michigan
PTP Offline
Carpal Tunnel
PTP  Offline
Carpal Tunnel

Joined: Aug 2005
Posts: 2,921
Michigan
Look closely at the mast luff track. Is the mast carbon? If so there can be cracks in the luff track that let the carbon track spread open and let the sail come out. This happened with my mast and was a somewhat cheap fix.
I like the outhaul/downhaul explanation better though. Besides, not sure if most A cat masts are carbon.

Re: A-cat - Luff track problem [Re: USA197] #106079
05/07/07 04:52 AM
05/07/07 04:52 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 9,582
North-West Europe


Same as USA 197 says but I know this problem in combination with mainsheet pressure.

Comes from the boom having an angle relative to the foot of the mainsail. It the foot is tight when the boom is still angled upwards somewhat then applying mainsheet tension will straighten the boom (relative to the foot) and thus require the foot of the sail to stretch (which it can't) or pop out of the sail track (which happens instead).

Solution : know where to trim the outhaul before indeed applying mainsheet (downhaul) pressure.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: A-cat - Luff track problem [Re: JoeLeonard] #106080
05/07/07 06:50 AM
05/07/07 06:50 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
second that - watch the outhaul. It will happen on any boat that doesn't have a limiter on the outhaul (the Inter's usually have a limiter line that you can restrain the outhaul so it doesn't go past the point of no return).


Jake Kohl
Re: A-cat - Luff track problem [Re: Jake] #106081
05/07/07 08:02 AM
05/07/07 08:02 AM
Joined: Oct 2003
Posts: 118
St. Louis, MO
JoeLeonard Offline OP
member
JoeLeonard  Offline OP
member

Joined: Oct 2003
Posts: 118
St. Louis, MO
Yes on Carbon...
no on cracks....although the inside of the luff track is tapered a bit at the entry slot, I presume for ease of boltrope entry, although I might be inclined to fill in the taper if I thought I could get it right.

I undoubtedly have been guilty of overtightening the outhaul based on what you guys are saying....that's an easy fix. I'll apply the lesson learned next weekend.


JL N20 # 1041 "Lucille" A-cat USA 44
Re: A-cat - Luff track problem [Re: JoeLeonard] #106082
05/07/07 03:06 PM
05/07/07 03:06 PM
Joined: Apr 2002
Posts: 805
Gainesville, FL 32607 USA
dacarls Offline
old hand
dacarls  Offline
old hand

Joined: Apr 2002
Posts: 805
Gainesville, FL 32607 USA
A-cat sails have a polyethylene tube sewn into the luff, 5/16 inch (8 mm) in Bimare/Zuccoli sails: there are 30 cm lengths of line sewn inside at the bottom and top to keep tubing from collapsing. The luff track slot is thin, and using tubing that is too large will NOT work.
If the tubing gets a little crushed or bent, it is much more difficult to push the sail up. AND it may pull out under tension, as you described. If so, put a strap around the front of the mast, or a bungee or a line through the clew, and tie it snugly but not too tight. IUt will not pull out then.

This tubing is larger at 3/8 inch in Ullmans, Ashby etc to match the larger luff track in Hall, Composite, Fiberform masts etc. Same problem, same solution: Either check and replace the tubing if crushed ($20) with polyethylene or harder polypropylene with 1/16 inch wall thickness.
IMHO 8 mm or 10 mm tubing is too weak with 1 mm walls and will not be satisfactory. Dont outhaul too much anyway....= wrong.

Dave Carlson
USA 196


Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison

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