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Question about mainsail troubles.

9K views 65 replies 21 participants last post by  casey1999 
#1 ·
Out sailing today and I keep having trouble with a steel cable that runs from the back tip of the mainsail boom to the top of the mast. The mainsail gets caught against it and it is rubbing on the mainsail. The cable is tight its not loose. The mainsail looked ok, what can I do to prevent this?
 
#5 ·
Try adjusting your topping lift. Probably located on your boom, look for a line (not wire) on a horn cleat. This line will allow your boom to be lifted higher or lowered, as needed. Typically, when sailing the topping lift is loosened to permit the boom to ride as low as possible, thereby allowing use of the boom vang and mainsheet to advantage.
 
#10 ·
Its main job is to keep the boom from falling onto the deck when you dont have your mainsail up. When the sail is raised, there should be enough tension that you do not need the lift at all. The only other time you might use is to keep the aft end of the boom up in very light wind to maintain sail shape. Observe your telltales in light winds, especially while running, to see if it is necessary.
 
#11 ·
Do you know if it's adjustable, or are you asking us (?) I can't tell from how you describe it.

What you want is for it to be just slightly slack when you have the mainsheet cranked in as hard as you would for sailing upwind, or as hard as you would ever crank your vang down. When sailing (except maybe in really light air as mentioned, but maybe not even then) you want the leech of the main to take the weight of the boom and the pull of the mainsheet, not the topping lift.

If there's no adjustment, then add one on, or a shackle or two, until it's just slack enough.
 
#13 ·
pogo

I am not sure I am reading your OP correct but the idea of a cable topping lift sounds off to me. If it is not line(rope) from front to back, I would suggest it be replaced.
A few thoughts on this;
- The replacement line can be quite light as all it has to do is hold the boom up when not sailing.
- Make the replacement line the same dia as your halyard that way it can be multipurpose.
- Use the opportunity to replace a worn/old halyard and use the old line as your topping lift.

John
 
#16 ·
Yep. That is called a topping lift and it holds the boom up.
The picture is good because it shows a length of doubled back line(rope) at the bottom that is evidently used for adjusting the tension in your topping lift. I doubt you have an adjustment for this line at the bottom of your mast (like a halyard) as it is a fairly primitive set up. OTOH maybe you do. If not you need to start loosening that section of line(rope) at the bottom of the topping lift once you raise the main sail and then re-tension it once you bring the sail down.
 
#17 ·
Yeah, slack it about 6 inches(?) and see if the batten tips don't free up and fall off to leeward. That should take care of the chafe problem. When you sheet the main in fairly hard, the topping lift should be just barely slack. So that may take a little further adjustment.

Looks like an eminently solvable deal, let us know how it goes.
 
#19 ·
My present boat just has a pig tail on the back stay, so I have no choice but to unhook it. But on my last boat, I always unhooked the topping lift. Why leave it flopping around? I would just clip it to the back stay and it never caused me any trouble. If I forgot, the sail wouldn't hang right and looked ridiculous.
 
#20 ·
With my main up, the boom will hit my dodger. Seems PO used the topping lift to keep boom from rubbing dodger. Does this mean the main sail is too long in the leach and luff? With the boom horozontal- it only clears the dogger by 6 inches. The doger is fixed and cannot be lowered.
 
#21 ·
Wow Casey,

That doesn't sound right. I'm thinking your dodger must be too high. I wouldn't think you'd want to change the shape of the main to compensate. But I guess if I were you, I'd do what I had to, to make it work.

Is there any chance you to adjust your main so it sits higher on the mast? Is there room at the mast head to do that? Seems like that would be a good way to go, even if you had to alter it a bit. I'm sure you don't want to loss that dodger. That's something I'm hoping to add to my boat. I have very little room in which to do it, so it will have to be a small one.
 
#22 ·
Wow Casey,

That doesn't sound right. I'm thinking your dodger must be too high. I wouldn't think you'd want to change the shape of the main to compensate. But I guess if I were you, I'd do what I had to, to make it work.

Is there any chance you to adjust your main so it sits higher on the mast? Is there room at the mast head to do that? Seems like that would be a good way to go, even if you had to alter it a bit. I'm sure you don't want to loss that dodger. That's something I'm hoping to add to my boat. I have very little room in which to do it, so it will have to be a small one.
The luff of the main is tight and no more room to uphaul further. The leech seems like it is too long as it will not lift the boom to the horizontal position which I would think it should do. If the boom were horizontal it would clear the dodger by about 6 inches which would be ok. My dodger is very low and should not interfere. Seems the sail should lift the boom to the horizontal postion which it is not doing- maybe it is blown out.
 
#23 ·
Can your boom adjust lower at the mast? But, it does sound like your dodger is a tad too tall as is,and if you lowered your boom on the mast, that would make matters even worse. I've seen oodles of folks worry more about "headroom" under their dodger instead of some trivial thing like, "sail shape"...lol
 
#24 ·
Sounds like either your dodger is too high or your sail is cut wrong. You should be able to get the specs of your sail and the correct angle of the sail cut between foot and luff. That will tell you whether the sail is the culprit. If this angle is around 90 degrees then the boom should look like it's at right angles to the mast with the topping lift slack. The topping lift is important because it stops the boom from falling on your head. I don't really trust them and have built a collapsible A-frame for times when the mainsail is not needed. This stops the boom from flapping back and forth (even when tied off) when the boat rolls if I'm motoring or under just headsail. The topping lift should be plenty strong and not disregarded as an annoyance. A boom, coming down on someone's head is no joke. It also can be adjusted just right so that the boom does not hit you in the head when you forget to duck!
 
#27 ·
Here is a pic with sail down. This weekend will try to get one with main sail up. The boom is at about 90 deg and clears the dodger by about 6 inches. With the main sail up, and topping lift slack, the boom can rub the dodger. the boom is fixed at the mast and cannot be raised or lowered at that connection. From above comments, when hoisted the main should allow me to have topping lift completely slack and then the boom should not hit the dodger. Once I hoist the main, I will do some tweaking to see if I can get it this way.
Regards
 

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