Shroud Tension

Apr 11, 2017
571
Catalina C22 Solomon's Island, MD
I wanted to ask what the more experienced members here think is the proper shroud tension on the C22.

I have a Loos PT1 gauge and was tensioning the shrouds this weekend on my new design 87'. Right now, I have them settled in at 10 for the aft lower, 25 for the uppers, and about 19 for the forward lowers, measured with the PT 1 Loos gauge. I have about 6 1/2" rake, measured at the boom. I should add the forward lowers are extended the full adjustment at this tension, and only have about 1 thread inside of the top turnbuckle, which seems awful close to the limit of the turnbuckle. I have the Catalina Direct quick release turnbuckles on the forward lowers.

In reviewing the C22 tuning guide by Pete Harper, the guide states - for medium winds - using the older Loos Model A gauge:
Uppers: 25
Forward lowers: 17
Aft lowers: 10

However, the North Sails tuning guide for the C22 states - using the older Loos Model A gauge:

Uppers: 28
Forward lowers: 24
Aft lowers: 24

I haven't had the boat in the water yet, so I haven't had a chance to see how they might slacken or tighten under pressure from the sails.

There seems to be a big difference of opinion as to the tension on the lower shrouds. Is there any consensus on this issue?

Also, what tension is generally recommended for the backstay and headstay? I wasn't able to find any real objective measurements. I have about 6 inches of headstay sag at the current set-up, with a CDI roller furler.

Thanks for any advice or comments-
 
Last edited:
Sep 30, 2013
3,538
1988 Catalina 22 North Florida
There's a lot of room for personal opinion, and heavy air calls for more tension than light. I generally leave the dock with about 6" of rake, uppers about 28, fore and aft lowers about 26. I've heard the racing set keeps their aft lowers much looser.

As to the forestay. If you lay your jib on the ground, you will notice the luff is curved. My understanding is that you want enough slack in the forestay for its curvature to match that of the jib, under whatever the conditions are at the time. The backstay starts out with very little tension, just enough to induce 1 or 2 inches of prebend in the mast. As conditions build, you can tension the backstay some more, to take the curvature out of the forestay, thereby flattening and depowering the jib.
 
Apr 11, 2017
571
Catalina C22 Solomon's Island, MD
Thanks Gene-

Do you know if that measured with a Loos PT 1 scale? From what I've read, the Loos Model A gauge reads a little differently than the PT 1, sometimes a little higher, sometimes lower. I know there's a conversion scale-

Is it common for the forward lower turnbuckles on the C22 to be just about stretched out to maximum length? At 19, I only have 1 thread inside the top screw fitting of the turnbuckle, and the mast rake at 6 1/2" seems to be about right. I believe the shrouds are the factory standards. It seems like the forward lower shrouds on my boat are a little on the short side for the application - all the other shrouds have about an extra inch of combined screw length available inside the turnbuckles.

Thanks again for the advice-
 
Sep 30, 2013
3,538
1988 Catalina 22 North Florida
Sorry - model A.

The situation with your forward lower turnbuckles sounds odd, especially since the others are at normal adjustment. I got nuthin.

Thanks Gene-

Do you know if that measured with a Loos PT 1 scale? From what I've read, the Loos Model A gauge reads a little differently than the PT 1, sometimes a little higher, sometimes lower. I know there's a conversion scale-

Is it common for the forward lower turnbuckles on the C22 to be just about stretched out to maximum length? At 19, I only have 1 thread inside the top screw fitting of the turnbuckle, and the mast rake at 6 1/2" seems to be about right. I believe the shrouds are the factory standards. It seems like the forward lower shrouds on my boat are a little on the short side for the application - all the other shrouds have about an extra inch of combined screw length available inside the turnbuckles.

Thanks again for the advice-
 
Apr 11, 2017
571
Catalina C22 Solomon's Island, MD
Thanks - great post by Leeward Rail in the link-

Part of it seems to imply the forward lowers are slightly longer then the aft lowers. Maybe the previous owner inadvertently switched them front to back in a re-fit on my boat. I might try reversing the forward and aft lowers, and see if that helps to fix the seemingly short current forward lowers.

Thanks for the help.
 
Apr 11, 2017
571
Catalina C22 Solomon's Island, MD
Does anyone know what the reasoning is behind some racers keeping the aft lowers under less tension?
 
Nov 19, 2008
2,129
Catalina C-22 MK-II Parrish, FL
The races leave the aft lowers loose to allow the mast to lay forward making the forestay loose for a nice powerful headsail for going downwind, (they only race windward, leeward), when rounding the mark, yank the adjustable backstay tight, which tightens the forestay for pointing to the windward mark.

Not being a racer, I simply follow the manufactures recommendations and set my stays following their simply instructions. Seems to work just fine, but my poor Loos gauge lays dormant in the parts box on board not having been used in many years leaving many in shock and disbelief. :yikes: Probably need to sell it someday because I never use it, but it seems that all the stellar C-22 Skippers seem to carry a Loos gauge on the boat, and so I guess it's just part of the being part of the fraternity. :pimp:

Don
 
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May 23, 2017
692
Catalina Jaguar 22 Simons Town
Allowing the mast to bend like a bow also flattens out the mainsail...