Rig tensions

[Noah]

Ok sailboat owners, lets talk about rig tension, and what you run.

Very little has been mentioned about what rig tension is correct for an older wooden sloop. I have a deck stepped alum mast, and I'm trying to figure out what tension I should be running. I have a Loos Model B guage, and usually go with around "30." Too tight, too loose?

[bamamick]

How many sets of shrouds do you have, and what do your sails look like? Your sails are really the deciding factor in how you set up your rig.

For example: on the Star and the Dragon we set the uppers really tight, because we don't want the rig to fall off any and dump the leech. We have other ways (backstays) to do that. The lowers we set rather loosely because we are a relatively heavy crew (maximum weight in the Star) and want the power that we get from a full luff.

On the gaff rigged racing boat that I used to have, we set the rig up medium tight, because we usually sailed with two people and most everyone else sailed with three. The boat gets over powered easily and I don't like having to play with the leech tension via the gaff. Too complicated, and you are always chasing your own tail.

What kind of boat do you have? Ask your class gurus or your sailmaker about rig tension. As far as your Loos gage goes, I believe that the Dragon guys recommend 40 for your uppers and 20 for your lowers, but I'll look it up and get back to you. My tuning guide is at work. That is, of course, set up for a 'glass boat, or a cold molded boat, with proper support under the deck to hold the boat together.

Mickey Lake

[ 05-25-2005, 11:57 AM: Message edited by: bamamick ]

[Noah]

Thanks for the comments. This boat isn't really a racer, so I'm just looking for some basic settings. There won't be crew on the rail, so that's not a factor. I do work to get a nice shape on the sails, but this isn't the Melges, so I'm not working outhaul, etc all the time.

Anyway, she is a single spredder rig with one set of uppers, and two lowers (fore and aft). There is no class association, so I can't start there.

Here is the best shot of the rig that I have, back when she was painted white.

http://www.morebutter.com/hinckley/exterior/on_mooring_white.jpg

[bamamick]

Well, that's a lovely boat. To be honest I just didn't know what kind of boat you had, but she's gorgeous.

I went and found the Dragon standards. Loos B measurements for heavy air, 30 for the upper, 16 for the lower. For medium air 26 for the uppers, 16 for the lowers. You get the idea. If you are at 30 on your uppers then you are probably pretty close, and you can probably just snug up your lowers to where they aren't sagging.

Mickey Lake

[Noah]

Yeah, that's about what I was thinking. I just didn't know what people with this type of boat actually run. I'm happy to let performance suffer a bit to make it easier on the hull.

It is probably time for me to purchase "The riggers apprentice" from Brian Toss.

Noah

[Stiletto]

Nice curve in the mast. smile.gif Do you alter it much when sailing?

[Ian McColgin]

How I do it. On a wooden boat I like to have as much stress as needed but not more. In consequence, my tuning finish needs a day when the wind is as high as I carry full sail.

I start with head and back stays hand tight and about where they always are. Then, using the jib hallyard (or main) to measure I adjust the uppers about hand tight to have the mast head centered. Then I look at how she's set in the partners and get the wedges in. Many masts are not centered fore and aft and you need different wedges. If she's not centered laterally, make sure that it's the partners that are off and not that you have a subtle bow in the mast.

Once we're happy, then we wedge. Then get the lowers a bit more than hand taught - what I call marlingspike taught in the end - with a 6" spike held fully in the hand, this will put about 20# torque into the turnbuckle.

Lowers are fun 'cause you can really confuse things. I usually start with the aft lowers, making sure the fore lowers are really slack. I trim to just barely induce a fore and aft bow and make sure there's no lateral bow. Then I trim the fore lowers to either straighten the mast or put a little convex in the luff line, depending on the rig goal.

Next, I get the head and back stays a bit more than marlingspike tight.

Now we go for a quick sail, noting if there is unacceptable headstay sag on the wind, the extent to which the lee shrouds are rattlingly loose, and the extent to which the mast head sags off. With the preliminary set, I've never had it that the uppers were too tight and that the mast bow-sagged at the spreaders, but that can happen.

If you're very careful, you can do some tightening under way. I like to get the uppers set first, tightening the weather side one side at a time till we get any sag out of the masthead. Then I go for the lee shrouds - lowers and uppers - just getting hand tight to take the slatty-slat out, tack on tack a little at a time.

This is a good time to confirm the fore and aft balance spot on. If you need to tighten to get rid of any jib luff sag, tighten at the backstay to add weather helm or headstay to reduce.

Once we have it that the mast is visually straight on each tack and that the lee shrouds feel unstressed but are not rattling about, we're about done. Time to anchor for a moment, strike the sails, and see that the mast head is still centered and that at rest there's no new quirks in the mast column. If all's well, a beer ration is allowed while pinning the turnbuckles.

If you've tuned this way, maybe adjusted the tune a little as the season goes along, and have a tension guage, you can record those tensions and somewhat speed the process next year. However, I find that wooden boats change subtly through the season and from year to year. I like to keep tuning th rough observation rather than guages.

G'luck