I am always second guessing myself as to whether my shrouds are tensioned correctly to give the mast proper support and at the same time not place to much compression on the deck of my OD25FK. The other day we were heeling between 25 and 30 degrees in a good stiff wind and when I sighted up the mast I noticed a slight bend to leeward above the spreaders so I took up another turn on the turnbuckles. Whenever we are heeling about 20 degrees or more the leeward shrouds are always sagging loosly. Is it necessary or proper for the mast to always be ramrod straight or is a little bend ok or even desirable? How much tension is to little or to much? Is there a good rule of thumb or is it just trial and error for each particular boat? Any info to ease my mind would be appreciated. Thanks Paul Palmer
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Rigging Tension
I had the same question about my rigging tension.. So I bought a Tension Gauge for about $43. It is a low tech gismo that you put on your stays and then read the charts. I learned that my stays and shrouds were a little loose and that being so puts extra strain on them, especially on the windward side. This gauge is a quick and easy to use way to size up your correct tension. You can find them in the usual marine catalogs. Paul ODay 23
I had the same question about my rigging tension.. So I bought a Tension Gauge for about $43. It is a low tech gismo that you put on your stays and then read the charts. I learned that my stays and shrouds were a little loose and that being so puts extra strain on them, especially on the windward side. This gauge is a quick and easy to use way to size up your correct tension. You can find them in the usual marine catalogs. Paul ODay 23
Proper Rig Tension
I have to agree with Paul, regarding the Loos tension guage. Once you know your rig size (1/4"?), you determine breaking strengths of that diameter and wire type. Then adjust the wire to a particular % of its breaking strength. A round # for cruising, would be about 15% for your outside shrouds, and about 12% for your inner shrouds. You then tension in, using the guage, these #'s. The lee shrouds will always be more loose than the weather shrouds. However, following the advice of sages like Brian Toss, they should not be floppy. Shock loads, as when falling off of waves and the rig slams back to weather can seriously damage chain plates, and swagged ends. In the last few years I have tightened my rig accordingly. Once you have done it a few times you get a feel for it. Hope this helps. Don
I have to agree with Paul, regarding the Loos tension guage. Once you know your rig size (1/4"?), you determine breaking strengths of that diameter and wire type. Then adjust the wire to a particular % of its breaking strength. A round # for cruising, would be about 15% for your outside shrouds, and about 12% for your inner shrouds. You then tension in, using the guage, these #'s. The lee shrouds will always be more loose than the weather shrouds. However, following the advice of sages like Brian Toss, they should not be floppy. Shock loads, as when falling off of waves and the rig slams back to weather can seriously damage chain plates, and swagged ends. In the last few years I have tightened my rig accordingly. Once you have done it a few times you get a feel for it. Hope this helps. Don
darn, got here after don again! 
An adendum to Don's post: A number of people I know leave their rigs loose because they are afraid of bending their boats a la America's Cup action. IMHO, if this is the case, you have work to do on your hull before you ought to be sailing. The shock load on the windward wires after rolling to windward and then healing back over are several _times_ greater than any static load you could put in with the turnbuckles. This according to our best local rigger. YMMV, Justin - O'day Owners' Web
An adendum to Don's post: A number of people I know leave their rigs loose because they are afraid of bending their boats a la America's Cup action. IMHO, if this is the case, you have work to do on your hull before you ought to be sailing. The shock load on the windward wires after rolling to windward and then healing back over are several _times_ greater than any static load you could put in with the turnbuckles. This according to our best local rigger. YMMV, Justin - O'day Owners' Web
From the Neil Pride O'Day guide
Adjusting the Shrouds: It is most important not to have a sideways curve in your mast. To achieve this it is better to have the Upper shrouds leading to the upper part of the mast taut and the lower shrouds somewhat slack. The uppers are longer and will stretch more than the lowers, therefore if the lowers are equally taut, a sideways bend is inevitable. The mast must be square. Take your main halyard and measure the distance from mast head to each of your chain plates. It must be the same.
Adjusting the Shrouds: It is most important not to have a sideways curve in your mast. To achieve this it is better to have the Upper shrouds leading to the upper part of the mast taut and the lower shrouds somewhat slack. The uppers are longer and will stretch more than the lowers, therefore if the lowers are equally taut, a sideways bend is inevitable. The mast must be square. Take your main halyard and measure the distance from mast head to each of your chain plates. It must be the same.
What is the shroud tension numbers?
Don Evans wrote: > Once you know your rig size (1/4"?), you determine breaking strengths > of that diameter and wire type. Then adjust the wire to a particular % of its > breaking strength. A round # for cruising, would be about 15% for your > outside shrouds, and about 12% for your inner shrouds. Given a 1/4" diameter stainless steel shroud, depending on the grade, the breaking load specs can range from 5500 lbs to 8100 lbs. 15% means 825 -1215 lbs of tension. Is this true? To me this seems excessive. The tension is not only dependant on the shrouds breaking load strength but on the hull and the mast's compressive strength as well. If the shrouds are made too tight then the mast has added compressive stress and is more apt to break. Consider also that a previous owner may have upgraded the diameter of the shrouds. If this is the case then tensioning to a percentage of the shrouds diameter may over tension the rig. Does anybody know the factory reccomended tension? Cheers, Gary
Don Evans wrote: > Once you know your rig size (1/4"?), you determine breaking strengths > of that diameter and wire type. Then adjust the wire to a particular % of its > breaking strength. A round # for cruising, would be about 15% for your > outside shrouds, and about 12% for your inner shrouds. Given a 1/4" diameter stainless steel shroud, depending on the grade, the breaking load specs can range from 5500 lbs to 8100 lbs. 15% means 825 -1215 lbs of tension. Is this true? To me this seems excessive. The tension is not only dependant on the shrouds breaking load strength but on the hull and the mast's compressive strength as well. If the shrouds are made too tight then the mast has added compressive stress and is more apt to break. Consider also that a previous owner may have upgraded the diameter of the shrouds. If this is the case then tensioning to a percentage of the shrouds diameter may over tension the rig. Does anybody know the factory reccomended tension? Cheers, Gary
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