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rpeskett · 21-09-2019, 09:04

Quote:

Originally Posted by MartinR

Horizontal spreaders must be fixed at the end. And the fixation needs to be substantial as there are pretty heavy downward forces here. If the spreaders are not locked, they will be experiencing bending moments, which they are not designed for.

The more common bisection spreaders should be fixed at the end, unless the mast fitting is very substantial and there is no risk of the spreader sliding. There are no bending moments on these spreaders until they go out of alignment, so the fixation can be less stringent.

Many spreaders have locking screws integrated into the ends.

Basic answer: Yes, they need to be fixated at the end.

Hi,
"There are no bending moments on these spreaders until they go out of alignment, so the fixation can be less stringent." That is very helpful.
Thank you,
Rick

**TrentePieds** · 21-09-2019, 09:06

Ann is right - and so is Benz. When the shroud angle is bisected, the spreader is protected from flexing and the load on the spreader is entirely compressive, which is as it should be. Sockets (on the mast) are often designed so the spreader will be at right angles to the mast, and that is wrong from an engineering perspective, but no doubt correct from the manufacturer's cost accounting perspective. This deficiency should (ideally) be corrected, and it's not too difficult to do by means of a hacksaw and the right welding gear. Obviously different boats require different angles due to different rig dimensions.

When the sockets are right, the outer ends of the spreaders should be secured so they cannot slide on the shroud. As long as the shroud angle is bisected the loads that would displace the spreader end on the shroud are fairly light, and a simple lashing with codline above and below the spreader end will do it. Wire clamps should not be used since they damage sails. Lashings don't.

TrentePieds

rpeskett · 21-09-2019, 09:16

Hi,
Thank you for writing. The spreaders do bisect the angle. It didn't occur to me to use clamps to maintain that. That seems to be better than nothing. The mast is down, so I assume wrapping with stainless wire would be better.
Rick

stormalong · 21-09-2019, 09:25

My rod rigging shrouds have fittings on them to prevent the mast tip from moving. You could probably do the same thing by wrapping some seizing wire or copper wire tightly around your shrouds above and below the spreader tip. Or you could use some wire clamps. I agree with what the others said about bisecting the angle. If you have any attachments to your spreaders, like flag halyards it would not take much force to pull them out of position.

rpeskett · 21-09-2019, 09:30

Quote:

Originally Posted by TrentePieds

Ann is right - and so is Benz. When the shroud angle is bisected, the spreader is protected from flexing and the load on the spreader is entirely compressive, which is as it should be. Sockets (on the mast) are often designed so the spreader will be at right angles to the mast, and that is wrong from an engineering perspective, but no doubt correct from the manufacturer's cost accounting perspective. This deficiency should (ideally) be corrected, and it's not too difficult to do by means of a hacksaw and the right welding gear. Obviously different boats require different angles due to different rig dimensions.

When the sockets are right, the outer ends of the spreaders should be secured so they cannot slide on the shroud. As long as the shroud angle is bisected the loads that would displace the spreader end on the shroud are fairly light, and a simple lashing with codline above and below the spreader end will do it. Wire clamps should not be used since they damage sails. Lashings don't.

TrentePieds

Hi,

Thank you very much. I'm going with your advice. It seems reasonable that the maintenance of the bisecting angle could be done this way, and you helped me realize the importance of doing it.

I never heard of lashing them with cod line. I've heard of doing it with stainless wire, but the ends of the wire need to be finished in a way that won't damage the sails, or hidden in a boot. The cod line would probably offer more friction and holding power than the wire, but I wonder how the cod line would hold up, regarding exposure to UV radiation and mold, mildew.

Thank you,
Rick

tidefalling · 21-09-2019, 10:00

Selden mast tuning guide is available online and says spreaders must be locked in position.

Cheechako · 21-09-2019, 10:29

I don't think you want them to not move. Everything stretches and moves, allowing some movement is likely a good thing. Short of sturdy clamps I doubt you are going to stop them from moving a bit anyway. If you really dont want movement design your rigging to terminate with fittings above & below the spreaders. You do need your spreaders to stay pretty much at the bisected angle though.

**TrentePieds** · 21-09-2019, 10:50

Quote: "...I wonder how the cod line would hold up, regarding exposure to UV radiation and mold, mildew. "

I have an affection for old-fashioned ways for doing things aboard :-) Doing things that way means that you never need "professionals". You can - if you choose as I do - do things yourself at very little cost and regardless of where you are. It also means that you always have "spares" aboard. MySaintedMother always told me, "If you can't mend it with a bit of codline and a shiv, don't go to sea in it.!"

Codline of the modern kind tends to be polyester and therefore UV sensitive. It does need, in many applications, to be renewed now and then, but generally doing so becomes an intrinsic part of the ongoing inspection routine in the boat. Depending on where you are, a whipping or lashing may last a year or it may last ten years. My "rudder indicator", a turk's head on the rim of my wheel made from common net twine readily available at chandlers, sits uncovered out in the sunlight summer and winter and has lasted five years now with no evidence of deterioration. In the days of natural fibres lashings would be secured and impregnated with tar. With modern cordage I like to use ordinary "yellow glue" which protects admirably against ingress of water, at the cost of a little more work with the shiv if the lashing has to be let go.

Another technique from days of yore that every sailorman should be familiar with is covering lashings with leather. If, for example, your spreader-end lashings have a leather sleeve sewn around them and the shroud for a couple of inches above and below the spreader end, and you fill the sleeve with tallow (or other convenient grease) before you stitch it up, you won't have to look at the lashing again ever. The turnbuckles at the chains will perish before the lashings, particularly if they are the type known as "bottle screws" rather than the open ones.

Mould and mildew require a certain quite narrow range of humidity in combination with still air to thrive. They are not a problem in applications such a this.

TrentePieds

Capn Jimbo · 21-09-2019, 11:58

Quote:

Originally Posted by rpeskett

Hi,

I’m leaning with going with the Dwyer staff member's statement and let the shrouds slip up and down, and I'm also leaning toward not using spreader boots (he also said they weren't necessary, for my spreaders). I prefer to be able to see the tips of the spreaders, from below, without boots, and I prefer to minimize water and corrosion. Aside from preventing damage to sails, I don't think the spreader boots do much to stop vertical movement.

Thank you for your time,

Rick

Here are the essentials.
.
1. Bisecting the angle is a must; but it doesn't have to be exact. The anal retentive will make the final adjustment after the mast and rigging are up and go up the mast - but an angle of about 7 degrees (up) on the spreader is close enough.

2. Can't tell but are your spreader tips aluminum or stainless - if stainless this is much better, but aluminum against the SS wire can cause galvanic corrosion. This is where boots are an issue as water can get trapped on the tip.

3. Chafe is MUCH better controlled by installing a simple, inexpensive Delrin wheel above the spread, which will completely eliminate chafe, while leaving the tip open to drain. Seize above the roller so it won't ride up the shroud.

4. All nuts at the bases should be locked with a cotter pin (file the tips of the pin to smooth them). The bases must have compression tubes or other means of preventing force from bending the mast.

5. Seizing the tip is essential but your tips will still allow movement, which will chafe the cod line. Don Casey and others use monel seizing which is very strong and stable. Ideally you can drill smaller holes to both sides of the larger shroud hole in the center. This way you can run the seizing around over the tip, then down through one hole, around a couple times below the tip, and back up over the tip. Rinse and repeat until the tip is completely stable - no movement whatsoever. The monel will last forever, or better until your next rigging check.

Hope that helps.

Michael Pope · 21-09-2019, 12:58

Trust me it is important that the rigging wire ( the Stay) be locked to the spreader end. Not so much for the normal functioning of the rig (holding it up by balanced loads on all the components) BUT to avoid making the mast fall down by accidental or other loading of the spreader that would prevent the spreader from doing its job..
CLASSIC "Silly Simbad" decides to hang his Mother in law using a flag halyard led thru a small block attached to the spreader.. M in Law is large-- spreader bend down --- Stay is relieved and allows mast top to bend enough to Make mast bend /break---- fall down smites "Silly Simbad" on his Bone Head and everyone laughs!
Use soft Stainless wire , Dacron or kevlar twine , Cover it with a piece of "Elk Hide" or similar soft leather ( to protect overlapping sails). Sew it in place BUT try and let Oxygen get to the place where the Stainless rigging rubs against the Alum or whatever spreader end. So the oxygen heals the wound with Oxide and not some other more dangerous corrosion. Pax Vobiscum!!
Pope Michael

CassidyNZ · 21-09-2019, 13:03

Quote:

Originally Posted by DefinitelyMe

Absolutely not. As others have said, the spreader should bisect the angle made by the shrouds so that it is only in compression. That may mean that it is indeed at a 'considerable upwards attitude'. Binding may or may not be necessary to acheive this. For me it is.

There are many professional sources to support this. This book is one of them. Covers all the basics, including spreader angles and rig setup.

https://www.amazon.com/Sailpower-Tri.../dp/1574091778

So in your professional opinion, if the angle at the top spreader and the angle at the second spreader differ, should they be on different planes? So the top spreader should angle up and the second spreader should be horizontal? Because at the second spreader the cap shroud is parallel with the mast.

And at the second spreader end, the cap shroud is vertical but the secondary stay angles in to the mast. Which angle should the spreader bisect? Because they’re significantly different.

Not sure on other members boats but on mine all the spreaders are parallel and horizontal. Must be wrong, I guess. Seems like Southern Spars who rigged the super yacht in the attached image got it wrong too. Maybe I’ll get my rigger to read your book.

Michael Pope · 21-09-2019, 14:35

Some confusion here . There are basically two general types of rigging "Continuous" and Discontinuous For Large yachts as per Pic they are usually using Rod or synthetic fibre prepared rigging which is manufactured to the exact lengths required for each part and joined at the ends of the spreaders which rigidly locates the position of the spreader PerSee no binding required
It is fixed and will not move. Good!
In smaller vessels it is easier to run a continuous rod from chainplate to Truck fitting(Mast Head) and lightly swage a spreader sleeve which has a small flange above and below the spreader which limits any up or down movement for the spreader end. Good. If wire is used fasten it in some way.
If you are in this or other ways restricting the vertical movement of the spreader end then all you have to watch for is a method of assuring that should the whole boat deflect and the stay become slack when the boat is heeling it cannot fall out of the slot in the end of the spreader or the plates or fittings that retain the spreader end at the mast. Then it works!
It may be aesthetically pleasing to some owners to have all the spreaders
Horizontal or some other angle. Or at the precise angle at which there is no vertical load transferred to the spreader at each spreader. If you try to do this it is more complicated as the loading case varies with the sails set. Staysail stays etcetc. It is just very embarrassing when the spreader end is swinging around in space and the stay is unconfined and slack . YOU SEE THAT BIG REEF JUST DOWN TO LEEWARD-------- How can we Tack? Dearly Beloved
Let us pray! Popemichael

DefinitelyMe · 21-09-2019, 15:01

Quote:

Originally Posted by CassidyNZ

So in your professional opinion, if the angle at the top spreader and the angle at the second spreader differ, should they be on different planes? So the top spreader should angle up and the second spreader should be horizontal? Because at the second spreader the cap shroud is parallel with the mast.

And at the second spreader end, the cap shroud is vertical but the secondary stay angles in to the mast. Which angle should the spreader bisect? Because they’re significantly different.

Not sure on other members boats but on mine all the spreaders are parallel and horizontal. Must be wrong, I guess. Seems like Southern Spars who rigged the super yacht in the attached image got it wrong too. Maybe I’ll get my rigger to read your book.

The superyacht in the picture has horizontal spreaders because the shrouds terminate at the spreaders, they don't run through them as in the case of the OP. That's what we are discussing here, and that is the situation that my previous post was in reference to.

To answer your question: if the shroud angles differ from one set of spreaders to the next (which they often do) then yes, your spreader angles should also differ accordingly.

Do you also want me to explain the 'multiple shrouds, single spreader' scenario? For most people the answer is 'make an educated estimate of the mean'. I don't think it applies here though does it?

I'm sure your rigger and Southern Spars have done a fine job. Do your shrouds terminate at the spreaders? Yes? Then kindly be quiet. Your situation and experience is not relevant to this discussion.

RaymondR · 21-09-2019, 19:30

Provided the shrouds are clamped to the horizontal spreader ends the extra compressive loading is very slight and there should be no bending loads applied to the spreader.