Fastening stays to spreader?

[Gerald]

http://www.imagestation.com/picture/sraid81/p3a93a3783d63e22a677463c0db0192ca/fb041713.jpg
The sun was setting as we fastened the last stay. Must admit to being a little bit nervous as we swung the 34' mast into place. We had taken it down in open ocean with the aid of the ladders but putting it back up again seemed a little bit more hairy.
The stays were secured to the spreader with duct tape and bailing wire. Bet that isn't the way they were fastened 35 years ago. I was thinking about using copper wire?
Gerald Niffenegger

[Nicholas Carey]

I believe they're usually lashed in place with stainless or monel wire.

[John E Hardiman]

Depends on what the shrouds are made of. While monel or stainless may seem like a good idea, the last set I did I used copper wire because the last thing you want is for the lashing to pit/corrode the wire and weaken the shroud (shroud=anode=bad :( ). Also remember that the shroud is siezed up tight by the lashing to prevent wear so the lashing should be softer than the shroud. You will need to inspect at least yearly, but that comes with having a sailing rig anyway

You could parcel and tar the whole shroud like they used to do with the old iron wire and then sieze with marline then tar. If you cover the wire/lashing, you need to be sure to keep the water/salt out.

[ishmael]

Interesting. I don't know this size rig at all, but I would have thought the shrouds were free to move in the spreader. I'm really ignorant. Explain how this works. I would have thought making the shroud fast to the spreader would create a hard spot in the rig. The shroud definately needs to be held from slipping out of the spreader mind you, but anchored along its length? I suppose the spreader is somewhat flexible.

Don't take any of my questions as something to doubt in what you've done or are doing. I simply don't know, and am asking.

[Gerald]

http://www.imagestation.com/picture/sraid81/p8bb1c18c78b4b1c570c4d6a2f85cfab1/fb03beb3.jpg
Here is a picture of the spreader. It is not one solid pc. but divided one half on each side of the mast. The stays are stainless and the end of the spreader has a shroud that is probably made from brass or bronze? Is too dark to check now but for sure it is non ferrous and it is not aluminum. Each spreader half can move a total of about 6" on the cable.
Ishmael .... it sure seems that the spreader should be held from working up and down the cable. But then again if I knew that for sure I wouldn't be asking? Brace your self because the questions have just started. This boat is getting close to going back in the water ..... soon.
Gerald

[John E Hardiman]

Ok Ish,
The reason that you seize the shroud to the spreader is two-fold. First, if the shroud can move on the spreader, the mast could be placed out of column. A mast is held in column against the substantial sail load by the shrouds. Each spreader forms a rigid triangle with the mast section above it. By allowing the hypotenuse to change, you allow the angle between the mast and the spreader to change, which allows the mast to fall off to leeward. As you may know, the Euler buckling limits the load on each mast section. As the mast falls off to leeward, the eccentricity of the mast column increases which decreases the strength of the mast by the distance cubed ratioed to the transverse span of the mast; [edit]i.e. 1” out of column on a 6” wide mast is a reduction in mast strength from 9/9 to 4/9 or greater than 50%[edit]. Granted, this may not matter much in short, single spreader rigs where the “standard” mast sections are hell’a stout, but it would cause a 3-5 spreader rig to fall down. The second reason is the spreader connection. If the spreader is “fixed” on both ends, the load at the mast is reduced significantly (by 6 IIRC, need to rework the math) which leads to a lighter spreader meaning less weight aloft, etc, etc,.

Additionally, there is the wear problem. If the shroud moved up and down in the spreader tip on every tack, you would soon wear through either the shroud or the spreader, neither which is good for keeping the rig standing.

[ 09-22-2003, 10:45 PM: Message edited by: John E Hardiman ]

[John B]

Drooping spreaders give a boat a downcast look and the natural progression of things is to sag( now isn't that a universal truth!) You can mouse those spreaders in place but after a sail or two and a tension up of the rigging screws they can get that droop to them. Also, theoretically( the books and many designers say), the spreader should bisect the angle the shroud makes. This is why you often see the the actual fittings force the spreader upwards. In practise however, " squared"... perpendicular to the mast, is fine and accepted. What I do to compensate for the retensioning of the screws and the rigging stretch is to stress the tips up an inch or two so they end up perpendicular or slightly lifted even after a tune up. I've just always used a stainless rigging wire myself( and an amalgamating type rigging tape.... one that bonds to itself)

[John E Hardiman]

John B;

To have to retension a rig often is a sign of waaay too much rig tension, i.e lee shroud should be just loose, never tight. Too much rig tension can 1) permently damage the shroud wire if it is too small and you are yeilding it; or 2) you're buckling the hull or driving the mast through the bottom. I've seen both and I would say that some of the problems a lot of wood sailers have with garboards are due to shroud tension. While the rig may need some taking up at first as the wine seats itself(or pre-stretch the shrouds), wire should never creep like the old fiber shrouds. If you're getting creep in the rig then somethings wrong in my opinion.

[John B]

I know what you're saying John. LOL. It's something to monitor. One well known Auckland yacht had the shroud tensions adjusted by the owner while she was sailing.He should have known better. she was hogged at the chainplates and ruined for life.(70 years approx... she was burnt by a vandal last year)

But wire does stretch, and that's what I'm talking about.
There's nothing worse than a depressed looking rig and it's bad mechanically too.It's amazing to me just how much I see it too. Just a little prestress UP is what I'm saying.

[Gerald]

If it weren't for my book Hand Reef and Steer, copyright 1965, I would be completely lost. I'm so damn green that I thought all cables holding the mast were stays. The information here is great, it actually helps me understand the book.
Thank You
Gerald Niffenegger

[John B]

Stays are generally for fore and aft tension, shrouds stop the stick falling over sideways. It goes a bit grey with things like swifter shrouds or even temporary backstays. you could argue that they do both (depending on the geometry of the particular rig). and meaning changes over history a bit too.( is a backstay on a Baltimore clipper really a shroud? What is a Cutter?)NO no don't answer :D .

[Gerald]

Well, it is far beyond me what you would call the four cables holding up the mizzenmast. They run forward and back but also hold sideways. But then again ...... like everything on sailboats ....... they probably have a special name? Can't find the name in my one book library.
Gerald

[John B]

That's what I mean!! :D

Shrouds is what they are .

[Carl Applebaum]

If anyone's still reading this thread,here's an actual answer to the question of how to fasten the spreader so it doesn't slide down the shroud:
Wrap a short section of the shroud--from an inch or two above the spreader to an inch or two below--with friction tape. That's the soft black stuff, not the shiny electrical tape. If you want to do it nicely, put a service (tight winding) over it with tarred marline. The total diameter should fit snugly in the groove at the end of the spreader.

Then you need to fasten it to the spreader. You will probably find evidence of one or the other of two pre-existing systems: 1)If there are two small holes drilled vertically through the spreader, there has been a seizing, or back and forth lashing, of wire (preferably monel or stainless). 2)If you don't find those little holes, there was probably a small sheet metal strap or band screwed into the sides of the spreader tip, going around the shroud, and thus clamping it into the groove. It might have been stainless steel or bronze. In either case, you don't have to worry about electrolysis with the shroud, because the tape and marline will isolate the seizing wire or strap from the shroud.

And by the way, in most cases you will find evidence of the previous angle of the spreader if you look at the tang to which it is fastened. Certainly it has been generally accepted as a good rule of thumb that the angles the spreader makes with the shroud should be equal above and below. This is so that the load on the spreader is aligned with its axis, and thus is chiefly one of compression (pushing it toward the mast, where it is opposed by the spreader on the other side), rather than bending the spreader. For a good basic discussion of how loads are distributed through a rig, try to obtain a copy of Brion Toss' book "The Rigger's Apprentice".

[Gerald]

Carl
I can see where the tape and lashing would solve several potential problems. Seems like a good idea to me.
Thank You
Gerald