loos gauge?

[wharfrat]

I recently got myself a Fibreglass sailboat. It's a Tanzer22. I want to drop the mast. When I hoist it again and set the tension on the stays and shrouds I understand I should use a Loos Gauge. What is this thing? Where do I get one? How do you use it? and is it really necessary. The specs are fore & back stays 900lbs. upper shrouds 750-850 lbs. lower shrouds 600-700 lbs.
Thank you in advance for any help

[Charlie J]

You should be able to get one at West Marine. You really don't have to have it because once you tune the boat you should only need to release the headstay to lower the mast, unless you have double lowers. Most trailerable boats do not.

What I do is back off the headstay turnbuckle a specific number of turns to slack the rig, then unpin the headstay and lower the mast. When I reset it, I just re-tighten the turnbuckle the same number of turns.

A much better place to ask questions about small trailerable boats would be on the Trailersailor bulletin board. Here's the URL
http://www.trailersailor.com/forums/trailersailor/index.cgi

[videoguy]

Warfrat I cant belive it you put a posting on the wooden boat forum admitting you just bought a boat made of the F#$@%$stuff and lived to tell about it WOW YOU GOT GUTS but good luck with the new boat and happy sailing.

[rodcross]

The definitive place to get your answer is to post the question on the 'SparTalk' section
of:
http://www.briontoss.com/

The short answer is you need the guage.

The long answer can be found in numerous books on rigging.

[Tom Lathrop]

A Loos gage is a device for measuring the tension in a stay. Some people believe that proper stay tension for racing requires such a gage. For a Tanzer 22, this is nuts.

Many people lose sight of the truth that the only job that the mast and rigging perform is to hold the sails up in the shape that the sailmaker intended. As long as the mast does this job and does not bend in pecular ways, it is ok for the average guy. No one ever had a forestay that was tight enough to prevent sag anyway. This is usually limited by flexing of the boat hull and stretching of the stay. Just set it reasonably tight without shooting the mast through the hull like a bow and arrow or bending the hull into a banana and you will be close to right.

Many books can tell you how to adjust the rigging properly for the different stay arrangments. "Sailpower" by Wally Ross is one of the best but there are many others. Check in you local library.

[Ian McColgin]

Tom's even more of an expert in reality than I am in my own mind and he's right.

It is possible to get the lowers a bit uneven, maybe starboard rear lower and a port forward lower are opposing each other such that the port rear lower is looser than the starboard. The guage will warn you of this almost as efficiently as simply pulling on the stays.

Sometimes the guage could be helpful at the start of the season to get the stays set at about the same tension they were at last year. If you happen to think that nothing has changed while the sticks were down and if you think that you had it about perfect last year, go for it.

The other thing a guage might do for you is make the tuning a one step rather than two step process. I get the mast centered side to side and in colum with what feels like suitable headstay tension and rake. That's always a tad loose for hard sailing. Then I tune under way. If you like guages better than on the water set up, go with the guage.

I think if I were running a club program and had say two dozen solings to set up in the morning, I might try to have a standard by the guage setting to start them all even. But for one boat at a time, I go the bad old fashioned way.

G'luck.

[Tom Lathrop]

Right Ian,

I'm not about to disagree with someone who says things that nice about me, waranted or not. I should have added though, that you have to know how to adjust the rigging properly before the tension gage will do you any good. The stays can be set to proper tension with the gage and the mast can still be bent in a wierd shape. Get the book so you can observe the process from beginning to end.

[ 06-03-2002, 03:10 PM: Message edited by: Tom Lathrop ]

[Todd Bradshaw]

I'll agree that having to buy a fancy gizmo to set the rigging tension on a 22' cruising boat with 220 sq. ft. of sail area is pretty far out in left field - about as far out as thinking that everything's going to be hunky-dory as soon as you dial-in the prescribed tensions on all the wires. If you really want the boat tuned well, skip the gizmo and use a small part of the money to buy a copy of "Boat Tuning For Speed", Dennis Connor's "Sail Like A Champion" or similar books that discuss rig tension in detail and explain how you can learn and observe what is going on and what to do about it. It's a pretty simple boat to rig and unless you're class racing in a hotly contested class, it shouldn't take long to arrive at a reasonably well tuned solution.

[HS]

Irrespective of what tension you put on the forestay prior to going sailing, you'll probably come back in with only 60 or so percent of what you started with. I'll bet the Tanzer is like most small plastic boats in this regard. GRP "creeps" under load and the whole hull "relaxes". I'll go along with Tom's pull it on until it looks good approach smile.gif

Hans

[Ed Nye]

Completely agree with Tom Bradshaw.
But, I do have one question. Well, forty years ago, I only had one question. Now, after 40 years of sailing and getting dumber every year, I have a million.
But, on rig tension, how tight is tight? Back when I was young and knew everything, on race boats we would crank on the stays until the bow came up a little (string from bottom of headstay to mast to bottom of backstay). On daysailors or cruisers, just tight enough to keep the mast more or less pointed up. Used to use one of those gauges on the race boats. On OPAL, I set the stays the way I think they should be and the amount of tension won't even register on one of those things.
So, how tight is tight?
Ed

[Ian McColgin]

My own rule of thumb is to tighten such that on a moderate - say 15 kt wind - the leeward shrouds are just a little loose.

I divide the strain between uppers and lowers such that the mast is straight when the boat's heeled over - no sag at the truck and no bow at the spreaders. Just sighting with a straighedge from the transom does it for me.

The reasoning is that it does not need tighter than that.

As for headstay and jib - if it's a stemhead tack with an opposed back or running back stay, I tighten to make the headstay sag on a moderate beat pretty minimal.

On older boats with bowsprits, Goblin and Grana, I run a bit looser and accept a bit of sag. Even cut the sail with that in mind.

G'luck

[Todd Bradshaw]

There are so many possibilities that it's hard to be really specific. On a typical cruising sloop, I usually set the outers fairly snug, the inners a bit loose and put enough tension on the backstay to get the forestay pretty tight and then go sailing. Then I lie on the deck while somebody steers the boat upwind and sight up the mast and slot. I want enough tension on the outers to keep the mast in column side to side, maintain the width of the slot and to keep the masthead from falling off to leeward or hooking to windward.

If there is enough flex in the mast, the looser lowers will often allow the middle of the mast to bow forward a bit when things are trimmed-in tight (combination of mainsheet and backstay tension). This eats-up some of the main's luff curve and helps flatten the sail for up-wind work. On some boats (fractional rigs) it may also help tighten the jibstay. The possible downside is that it can also cause the rig to pump (mid section of the mast wandering about, rather than staying put) which is bad for speed as the rig and sailplan are constantly changing shape. In that case, I'll tighten the lowers a little to see if I can get it to stop. Given the choice, removing pumping is usually more beneficial than being able to flatten the sails a bit more. Some rigs even work best with a bit of pre-bend tuned into the rig to stop pumping and stiffen the mast.

In the case of adjusting the backstay tension or any mast pre-bend or when trying out the loose lowers idea, it's worth watching for an "overbend wrinkle" in the mainsail. This is a crease that starts at the clew (outhaul), runs diagonally up and forward and ends at the luff about halfway up the mast. While not always an obvious detriment to speed and sailshape, it's a pretty good sign that your mast bend is starting to exceed the luff shape designed into your sail and it's probably a good idea to back off a bit on the backstay or snug-up the lowers a little to prevent the mid mast area from moving forward so much.

Obviously, boats with flexible masts are going to behave more radically when you do these things than boats with big stiff masts, but even they will be affected to some extent. The typical cruising mainsail only has 2.5%-3% of it's chord widths added to it's luff side to form the luff curve and it doesn't take much mast bend to affect the sailshape, especially with the current generation of highly resinated, firm fabrics.

The best way to judge headstay sag is to get off the boat. Sit in the dinghy and have them sail upwind toward you. You can lie on the deck and sight up the wire, but it's hard to get very serious when you're trying not to fall overboard and it's not a good angle to view from anyway.
Ideally, there will be none, but that's never going to happen. For upwind sailing in particular, less is best.

[ 06-04-2002, 05:41 PM: Message edited by: Todd Bradshaw ]

[Tom Lathrop]

There is never going to be enough information on this forum to cover all possibilities. I still recommend a good book with illustrations. Todd covered some rigs well but, and a big but, how about fore and aft lowers, single lowers with swept spreaders, both with straight spreaders, multiple spreaders, masthead or fractional rig, adjustable backstays, B & R rigs, etc, etc, etc.

Get the book!

The comment about loose leward upper stays is a good one. Most boats will have the leward stays loose in less than 15 knots though, since few hulls are stiff enough to maintain tension in these winds. This brings up an important point about stay tension. No matter how much tension you crank in on the uppers at the dock, the tension on the windward stay will be exactly the same when on the wind in enough breeze to make the leward stays loosen up a bit. The main thing is to have the stays balanced so that the mast stays in the shape you want and not over the side in a tangle.

Get the book!

[ 06-04-2002, 06:33 PM: Message edited by: Tom Lathrop ]

[Todd Bradshaw]

Yep, and it's also worth checking the web for a class association forum, or similar. In many common classes the members have figured out tweeking tips over the years that seem to help on that particular boat.

[Larry Exum]

Wharfrat,

Send me your mailing address and I will give you my Loos Guage, No charge. I have found it valuable over my 20 years of sailboat racing. It works by attempting to bend the rigging wire sideways. The more tension the wire has the harder it is to bend. There is a spring bar which has a guage to read the relative tension. I have never found them to be accurate like a Torque wrench would be, however, all you are doing here is making sure that the port and starboard lowers are the same tension, and that the port and starboard uppers are also of equal tension. I have never heard of anyone using it for forestay or backstay. It proved to be a good tool for me, as I have won 140 plus sailing regattas over the past 20 years, 17 of those years on a 27' Catalina 27.

Forgive me Forumites, I was once an EVIL Plastic boat owner. I still own the Catalina, but have it in a charter service to take care of her while I spend my time with my Chris Craft Constellation.

[Ian McColgin]

I'm gonna happily chide Larry a bit because I doubt that the Loos guage had much to do with his winning races, even if he thinks so.

If you're just using the guage to get the stays even, you're not using much of its capacity. You can feel evenness very accuratly by hand and it's hard (though, as alluded to above not impossible with lowers) to get opposing stays to be uneven. The mast may look like a sine curve, but the stays will be even.

More races are won by boat speed than were ever won by tactics. More boat speed comes from handeling and sail trim than comes from ultratweeking of the tune, but when you look at the winners, that ultratweek is by feel, even if first set-up was by guage. Or, in boats that are dry sailed, the tune is established by feel and then replicated by guage.

If you're paying attention to boat speed you will, perforce, be paying attention to sail trim and rig tune is, after all, simply a part of the sail trim.

Hang loos(e) and G'luck

[Don Z.]

Guys... This is a $50 item at the local West Marine... Probably cheaper if you find one at a place like Minney's in Newport Beach. YES, we can use the above methods to find out what is right... specs be damned, use the tuning methods Tom&Tom talked about to get it right... then...
Use the $50 for repeatability. Why guess when you can measure? I could simply look at the tires on my car to see if they need air... instead, I measure it.

[Larry Exum]

Ian,

The secret weapon to my winning the sailboat races was not really the Loos Guage, but the Loos Female I kept below decks. When a competitor would close in on us, my voluptuous babe would pop out of the hatch, naked, run around the mast, yell out "I'll be right back", and run back inside. The competition would spend the rest of the race watching my hatch for her reappearance that they could not concentrate as they watched us pull further ahead.

And not one Protest was filed !

[wharfrat]

great replies you guys. thanks to all and I hope you got my mailing address via e-mail by now Larry