Shroud Tension?

[alsantini]

Ok, first off I am new to the Horizon, and have tried to find information on Shroud tension with no luck.  This last Thursday I sailed for 7 hours in 12 mph winds - a great day.  But, the lee shroud flops around.  This can't be totally normal.  I am hesitant to just crank it down without a reference.  I have a Loes gauge.  Does anyone have a recommended setting and how loose are your lee shrouds in a decent wind?  I can see that the mast moves side to side at the split where the hinge is.  My guess is this is putting a lot of force sideways on the hinge.
Any reference appreciated.  Sail On, Al       BTW, I think this is the best boat I have owned!  I love it.

[bruce]

Glad you like the boat, Al!

This is a common question for all the catboats. Com-Pac's advice had been consistent. Tension the rig so the forestay lever snaps closed with a firm force. The mast should be vertical and straight, no rake. At rest, the shrouds will be taut, but will deflect readily. Underway the lee shroud will be notably slack. I have never seen a Loos gauge setting offered by Com-Pac.

I would check to verify that the mast was still indeed perpendicular and straight underway. Maybe have a buddy boat/observer confirm your observations if possible. If the mast looks OK I wouldn't tension the rig further, if it's off perpendicular significantly, adjust accordingly.

Here's a few older threads to read through. Check out the videos linked in the second thread. There have been reports of the mast step on the HC being damaged by over tensioning the rig.
https://cpyoa.com/forum/index.php?topic=8388.0
https://cpyoa.com/forum/index.php?topic=3582.0
https://cpyoa.com/forum/index.php?topic=6442.msg46185#msg46185
https://cpyoa.com/forum/index.php?topic=9583.msg72203#msg72203 (reply #2)

[alsantini]

Thanks Bruce.  This week when I put the boat back in the Chain of Lakes, I will pay attention to the lever.  Thanks again.  Sail on,  Al

[Cpy23ecl]

I've never had a gauge, but I've always set shroud tension by going out in 10-12 kt winds and adjusting the leeward shroud so that I barely remove any flop without really adding tension and then tacking and doing the same on the other side.  Then I check to make sure the mast is level at the dock and if necessary loosen one side and tightening the other side by the same amount of partial or full turns of the turnbuckle.

Fred

[passagesfromtheheart]

Some years ago, I recall I had contacted both Keith Scott of The Sailboat Company, as well as Gerry at Com-Pac, to ask about tuning the rig (on my 23 and on my Legacy) — in other words, to ask them how do I know if things are 'as they should be' with respect to tensioning the rig properly. I do remember Gerry saying that there was no numerical value he could provide to me as far as using the Loos gauge tool as well, like you mentioned, Bruce. What they both told me, to be honest, didn't seem to help me fully understand what I was looking to do in order to have peace of mind with the rig. Back then, I was too shy and embarrassed to tell them "I still don't understand" — I was too concerned with being bothersome to them with my add'l questions, etc. I admit, sometimes it takes some time for me to figure stuff out. ;-)

Anyhow, the above all said, the First Mate and I worked with a captain, a couple of weeks ago, on our Com-Pac 25 and we did go over tuning the rig with him. The first thing he told us was to look at the mast - specifically, he told us to focus on the track (where the mainsail would go up the mast) and that doing so would give us clues if the mast wasn't straight. Our job with tensioning the rig was to make sure the mast was straight — that was the goal. Also, we only discussed mast rake with respect to racing boats adjusting this with the backstay, which we didn't do, of course. After we tuned the rig in our slip, the captain did also tell us that, once undersail, we would fine tune and would look at how loose our leeward shrouds were and make adjustments from there. From this exercise we learned our starboard forward lower shroud was a bit loose and needed a bit of adjusting.

[Roland of Macatawa]

Hi, Al:

The following are excerpts of comments from a discussion between me and another SunDayCat owner about sidestay tension and forestay tension and the mast hinge.
Presuming that the HorizonCat mast hinge is similar to my SunDayCat mast hinge, these may be useful to you.
Decide for yourself if these comments ought to be extrapolated to your situation.

I believe that with our mast hinge it is essential for the mast to always be fully seated upon the mast stub.
Thereby, the downward component of the forces from the tension within the stays are carried through the compressive joint contact and not by the hinge pins.
Also, the lateral bending moment and shear forces are carried by the mast hinge's collars/flanges rather than by flexing and twisting of the mast hinge ears.

Tensioning of the sidestays acts towards pulling the hinge open from its fully seated position.
Opposing that, there must be sufficient forestay tension to hold the hinge fully closed.

To rake the mast back to gain more weather helm and possibly better pointing ability by allowing the hinge to partially open abuses the hinge.
The SunDayCat has some natural weather helm from its large gaff sail, no more is needed.
I presume the HorizonCat is similar.

I encourage you, as you tighten sidestays, to be aware of maintaining sufficient forestay tension to hold the mast hinge fully closed.

Regards, Roland

[brackish]

The Loos guage doesn't give settings based on boats as might be expected.  The guage information is based on the diameter of the standing rigging component.  And it gives minimums for that commenting that professional riggers go from there based on use, i.e., racing, cruising or what.  I cannot comment on the HC, but I use the minimum on my 23IV and it helped me to not do what almost everyone who tensions by feel does, and that is go way under.  In this case the settings were 350 for shrouds, both upper and lower and 500 for forestay and backstay. Works well for me.  If you need the size minimums I've got them although they are probably available online.

[bruce]

Another reason to regret Com-Pac closing its doors. One thing I liked about their website was the link to their parts listings for all their boats. I would often compare similar parts for the catboats, in part to be sure I wasn't blowing smoke having only hands-on experience with a PC. It was interesting to see how often the exact same part listed for the various models, not just a similar design but the same part number. I don't recall offhand about the hinge for example, but they would, at times, make one version, designed for the highest loads, and use it across the product lines.