Shroud tension

[Buzoman]

I live on my 1980 36' union cutter. On a mooring I recently pulled my engine using the boom. I tightened up the staysail and headsail shroud a little when I was living from the boom. Now I've put my engine back in and all is well but all my shrouds are a little loose. I'm no sure how much tension to put on them. And is there an order to follow when going thru and adjusting? Last time I went sailing the leeward shrouds were sloppy loose and I don't think that is right. Any advice? When I first got the boat about 5 years ago I hired a reputable rigger to come out. They sent out some hippy kid who just banged on them and slightly adjusted a couple of the shrouds and said yup looks good. Git a bill for $250. Seems like I could figure it out....

[double u]

here you go: https://support.seldenmast.com/files.../595-540-E.pdf

[danstanford]

Originally Posted by Buzoman

I live on my 1980 36' union cutter. On a mooring I recently pulled my engine using the boom. I tightened up the staysail and headsail shroud a little when I was living from the boom. Now I've put my engine back in and all is well but all my shrouds are a little loose. I'm no sure how much tension to put on them. And is there an order to follow when going thru and adjusting? Last time I went sailing the leeward shrouds were sloppy loose and I don't think that is right. Any advice? When I first got the boat about 5 years ago I hired a reputable rigger to come out. They sent out some hippy kid who just banged on them and slightly adjusted a couple of the shrouds and said yup looks good. Git a bill for $250. Seems like I could figure it out....

Please have a look to insure it isn't something other than stretch. If the mast base is at all soft or the chainplates have issues this could cause the lack of tension and could be catastrophic if they fail, especially if you tighten them further.

[wingssail]

Adjusting the shroud tension (tuning the rig) is easy and mostly common sense. You need only simple tools and expensive gauges are not required.

Of course check the mast step, chainplates, shrouds and stays. Usually a rig does not go slack without a cause, so look for that.

When you are satisfied that all you need is a rig adjustment then proceed:

1. center the mast athwarts ship by using a long tape measure hoisted on the main halyard. Measure to each side of the boat and adjust the cap shrouds until the mast is centered.
2. Take up on the lower shrouds until the mast looks straight, not curved. Put your eye right at the mast track where the goose neck is and sight up the track. Make the mast straight and the shrouds just tight.
3. Go sailing in 8-12 knots of wind, sailing upwind with the sails close hauled
4. On first one tack then the other take the slackness out of the leeward shroud and continue to sight up the track, watching for any curve. It should be straight.
5. If you see any curve or fall-off of the tip, tack over and tighten the shrouds on that new leeward side, then tack back to see if you have achieved a straight column.'
6. Repeat as needed. Always tack over and make adjustments on the leeward side then tack back to see the result.
7. The adjust the other side similarly. Look at it, tack over and adjust, then tack back and look again.
8. You can accept some backwards bend but do not accept any tip bend forward. Easing the aft lowers slightly then tension the backstay which will induce some bend of the tip aft and the middle forward which is OK.
   
9. After adjusting shrouds then look up the headstay. The sag in the headstay should not be over 1 foot or so on your boat. It is it more than that, then back at the dock tighten the forestay turnbuckle until the tip of the mast starts to go forward, then tighten the backstay to put the mast in column again. Remember, no forward bend in the mast,
   

After you have gotten the mast straight in the boat, in column, and removed the looseness in the shrouds and tuned the mast then check the balance of the boat when sailing upwind. You want slight weather helm in 8-10 knots going upwind. Move the mast tip aft for more weather helm, and move it forward for less weather helm, but minor adjustments only and do not let the mast bend towards the front of the boat. That is called "inversion" and is dangerous. Further fine tuning may require a good sailmaker on a sea trial/tuning trip.

[Buzoman]

This is great! Thanks!!

[Manateeman]

We’ve seen more damage caused by over tension than loose rigs.
The recommendations on how to tune your rig? Nice if you are in a race, and “athletic” enough to jump out of the way when stuff falls from above and wealthy enough to buy more spars and rigging.
We thought this was a forum for cruising so we will dispense with how to do race boats.
Think about violins. They are tuned tight for a performance then the tension is relaxed. Some have lasted a long time following this procedure.
The manatee crew of professional boatbuilders.

[wingssail]

Originally Posted by Manateeman

We’ve seen more damage caused by over tension than loose rigs.
The recommendations on how to tune your rig? Nice if you are in a race, and “athletic” enough to jump out of the way when stuff falls from above and wealthy enough to buy more spars and rigging.
We thought this was a forum for cruising so we will dispense with how to do race boats.
Think about violins. They are tuned tight for a performance then the tension is relaxed. Some have lasted a long time following this procedure.
The manatee crew of professional boatbuilders.

The recommended procedure should not be rejected simply because it comes from a racer, it applies to all sailing boats with masts supported by standing rigging.

There is no reason to over tension the rig on a cruising boat. The recommendation baseline tension is to take the slack out of the leeward side when the boat is heeled. It should not be floppy, just snug. Race boat or cruising boat.

After that it is important to get the rig in column, race boat or cruising boat.

And taking excess sag out of the headstay is also common sense.

We didn't go into the specific details for boats with swept back spreaders or how to use mast bend to shape mainsails or use of mast jacks, etc. These won't be useful for a Union 36. Our advice is simple and basic, It is a good place for any boat owner to start.

[Manateeman]

A good place to start ? Well it might be to recognize sailing is NOT necessarily an “athletic “ activity. It’s a cruising forum.
My potato shaped crew is perfectly happy to see others enjoying their boats at the dock or at anchor.
Now as to the “ recommended procedure “. These steps have been outlined by numerous authors. Nothing wrong when applied by skilled hands. Unfortunately, these instructions cannot account for all the issues professionals encounter.
The do it yourself owner sometimes continues to over tighten the rig especially in an ill advised attempt to correct helm problems.
We never give advise on how to tension rigging.
We stand behind our previous post. If someone has to ask how to do x or y rigging, we suggest they hire a professional and watch carefully, read several books and spend time learning fundamental engineering and yacht design.
We leave it up to forum members to evaluate the experience level and professional credentials of posters.
Captain Mark.and the manatee crew

[double u]

....conflicting "evidence"...
37' aluminium , masthead-rigged keelboat, "reasonably" well tensioned shrouds, discontinuous, 2 in-line spreader rig
guests climbing up from their dingi, grabbing the shrouds.
on one occasion: "wow, that is tight! I wonder that you haven't lost your stick yet! Your boat can stand this much tension?"
others, on another occasion: "...now this is slack! I wonder that you haven't lost your stick yet!"
hmmmm...