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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

shroud tension by the book???

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Old Disco Queen
1st Mate

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USA
66 Posts

Initially Posted - 04/19/2009 : 15:12:47

so..
I purchased over the winter a tension measuring guide for the shrouds?

What does the book say it needs to be for a non-racing /cat 25 standard rig (non-racing)?

Old Disco and I thank you much!
Stephen

Stephen J. Moore

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Steve Milby
Past Commodore

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Response Posted - 04/20/2009 : 03:03:45

Most people, myself included, don't use a Loos gauge to adjust the tension in their shrouds, and, to be honest, most of us don't know what tensions are recommended by any authoritative source. Some people on the forum use Loos gauges,and they will probably tell you what tensions they use. If you'll use the following procedure, the mast will be erect, straight, raked properly, and the shrouds and stays will be tensioned very close to the optimum. If you use a Loos gauge, you'll still need to follow this procedure, to get the mast oriented correctly before you tension the shrouds and stays.

These instructions are for a boat without a backstay adjuster.

The first thing you need to do is raise the mast with all stays and shrouds adjusted loosely, but secure enough so that the mast won't fall.

The first adjustment should be made to the upper shrouds. Adjust them so that the mast is erect laterally (i.e., not leaning either to port or to starboard.) When it's erect, snug the uppers down until they start to become taut, but not bar tight. For the moment. all adjustments made to the turnbuckles should be made by hand. Don't use a tool, such as vise grips or a screwdriver. When you're snugging them down, alternately tighten the turnbuckle on each side by an equal number of turns. At this point, the uppers should not be snugged down so tightly that they cause the mast to bow in any direction. The mast should be in column.

Next, adjust the headstay and backstay so that the mast rakes aft about 2". You can use the main halliard to measure the approximate amount of rake. When the mast has the correct amount of rake, start tensioning the headstay and backstay by alternately tightening the turnbuckle on each by an equal number of turns, until they are both snugged down, but not bar tight. The mast should still be in column, without any appreciable bow in any direction.

Now, alternately adjust all four lower stays by hand until you have taken all the slack out of them. Except for the slight 2" rake aft, the mast should still be erect and in column.

If the middle section of the mast bows forward too much, then ease each of the forward lowers by a turn or two, and tighten the aft lowers the same numbers of turns, until the mast is erect and in column. If the middle of the mast bows aft too much, then ease the aft lowers and tighten the forward lowers. If the mast bows to port, then ease the port lowers and tighten the starboard lowers by an equal number of turns, and visa versa if the mast bows to starboard.

When all adjustments have been made, use an appropriate tool to tighten the headstay, backstay and uppers by about 2 turns each, and use a tool to alternately tighten each of the lowers by about 1 1/2 turns each.

Lock all the turnbuckles in place with lock nuts or rings, or whatever you use for that purpose, and take the boat out to sail. When you're beating to windward in 10-12 knots of wind, check the tension on the leeward uppers and lowers. They should not be slack. If they're slack, then alternately tighten each shroud and stay by an equal number of turns just enough to eliminate the slack, but no more. Also, when the mast is under load, it should remain in column and erect, except for the 2" rake. If it isn't, make the appropriate adjustments to the lower stays to correct it.

The object is to adjust the rig so that the mast is secure, and so that it doesn't move fore and aft or to one side or the other as it tacks from one side to the other, but the shrouds and stays should be no tighter than is necessary to achieve that. They should never be bar tight.

If the boat has too much weather helm, you can reduce it by reducing the amount of rake in the mast, but remember that you only have a couple of inches to play with, and you don't want it perfectly erect. You always want some rake.

Assuming someone furnishes the tensions that they use, you can use the Loos gauge to check them at this point to be sure your adjustments are close to optimum, but, if the mast stands correctly, and behaves correctly when under load, the tensions have to be very close to optimum.

Edited by - Steve Milby on 04/20/2009 03:14:26

pastmember
Master Marine Consultant

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Response Posted - 04/20/2009 : 04:51:30

The Loos gauge is more to speed up rigging after you have gone through Steve's procedure. I sailed with a tight rig so after I had it where I wanted it I used the Loos to make sure everything was equal, then I was able to "get there" more quickly the next time I put the stick up by using the Loos. I think my uppers were 23 and my lowers were 18, but I don't remember which model gauge I used.

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Windhover
1st Mate

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Response Posted - 04/21/2009 : 11:03:28

Steve, thanks for taking the time to detail that procedure. When I bouight Windhover last spring, the mast had been stored stepped, and I didn't bother to adjust any of the rigging, other than visually inspecting it. I am launching Friday and had a basic idea how to tune the rigging, but this really really helps.

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Old Disco Queen
1st Mate

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Response Posted - 04/21/2009 : 19:06:12

But... What if my boat (on the trailer) is not sitting exactly "straight" on the trailer? When the hoisted it last fall...they put it a little bit crooked (tilting slightly to port)...well. OK

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Steve Milby
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Response Posted - 04/22/2009 : 01:25:10

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Old Disco Queen
 But... What if my boat (on the trailer) is not sitting exactly "straight" on the trailer? When the hoisted it last fall...they put it a little bit crooked (tilting slightly to port)...well. OK
<hr height="1" noshade id="quote"></blockquote id="quote">You shouldn't tune the rig when the boat is on the trailer. The boat should be in the water, floating on it's lines, preferably pointing into the wind, or at least on a day when the wind is light enough so that it isn't causing the bare mast to lean appreciably.

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Even Chance
Captain

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393 Posts

Response Posted - 04/22/2009 : 04:09:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Old Disco Queen
 But... What if my boat (on the trailer) is not sitting exactly "straight" on the trailer? When the hoisted it last fall...they put it a little bit crooked (tilting slightly to port)...well. OK
<hr height="1" noshade id="quote"></blockquote id="quote">
Also, use a tape measure attached to the hoisted main halyard to measure the distance to a fixed point on deck, like the chainplates. That compensates for any heel in the boat, whether wet or dry.

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Tom Gauntt
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Response Posted - 04/22/2009 : 06:02:43

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Even Chance
 Also, use a tape measure attached to the hoisted main halyard to measure the distance to a fixed point on deck, like the chainplates. That compensates for any heel in the boat, whether wet or dry.
<hr height="1" noshade id="quote"></blockquote id="quote"> Brooke, that is a great tip! I had envisioned using a 6-foot level across the cockpit to level the boat then using a 2-foot level on the mast, but it seemed to introduce a lot of little errors.

I am going to use your suggestion. I think I might try using the topping lift wire first before running a tape up the mast.

Thanks for the tip.

Edited by - on

Steve Milby
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Response Posted - 04/22/2009 : 06:53:05

You can also measure it with the jib halyard, by adjusting it until it just touches the forward lower chainplate on one side. If the mast is straight, it should also touch the forward lower chainplate on the other side.

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Tom Gauntt
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Response Posted - 04/22/2009 : 06:59:48

Steve,

Thanks! Even better!

And thanks for your ideas earlier on rig set-up. I actually printed that post out to keep on the boat.

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HeelinPatrick
Navigator

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Response Posted - 04/23/2009 : 14:50:06

Thanks too Steve, I just redid mine last nite. Makes sense too after doing it. I swear though, the mast bows to one side just a little, right at the boom, but not an S-bow. But this is me with my head at the boom, looking up the mainsail track. I don't plan on taking the boom off as its pretty damn close either way.

Borrowing a friends gage to see what the tensions are just as a reference. Hopefully going for first sail tonite!

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Dave Bristle
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Djibouti
10005 Posts

Response Posted - 04/24/2009 : 08:28:57

I used a halyard to measure verticality, but I suspect Steve's procedure will be tough if the boat is listing on the trailer--the leaning mast will make it difficult to get the tensions (port & starboard) right.

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