spreaders

[tyce]

hi,
i think i have made a bit of cock up with rigging my mast.
i renewed the standing rigging this year and refitted it myself, when i ran my cap shrouds thro the spreader end plugs, i did not tighten/lock the shroud in place with the clamp, i just tightened it enough so the shroud can run thro the clamp, assuming that is how you get the tension above the spreader to mast connection.
now i have a funny feeling i should have locked it off tight, is this correct and is my mast about to come tumbling down.
any advice on how i should have done it would be much appreciated.
thanks in anticipation
the mast is a fractional swept back single spreader on a hunter horizon 272

 

[Vara]

Recent post on the subject

Yes you have a problem but the above click looks at it in detail. [ QUOTE ]
IMHO I don't believe that shrouds should normally be free to run in the spreader ends. I do not believe that they will normally find their 'natural correct position'.

Furthermore on nearly all rigs, the spreaders should 'bisect the angle' of the shrouds. This is easier to draw than to explain! Also the idea of the shroud 'moving down to a horizontal position' as the boat sails and pressure comes on fills me with horror!

One way that a rigger showed me to find the correct place for the spreader to be attached to the shroud was to bring the shroud down close to the mast and then mark the exact point on the wire where it passed the root of the spreader. You then take the shroud out to the end of the speader and fix the spreader at this point.

On a wooden boat we had once, with a wooden mast, and wooden spreaders, I used a bulldog grip beneath the spreader end to ensure that the spreader was held 'up' at the correct position. I can't remember a modern spreader that didn't have the facility to lock itself onto the spreader.

There was a time when riggers didn't appreciate the forces involved, and you will sometimes see older boats with 'horizontal spreaders'. If they survive it is a tribute to their over engineered design.


[/ QUOTE ]

The above from John Morris probably addresses the issue most directly.

 

[steve6367]

Mine run freely..............mast has been up and down but they have always been that way. Never had any problems. Got me thinking now though!

 

[William_H]

Colmce is probably strictly speaking correct howver mine are free running.
The theory is that the load on the spreader should be totally in column compression. That means the spreader should meet the stay at rightangles to the wire or at least equal angles. Now that is all fine for a standard mast head rig. However your fractional rig has aft swept spreaders which are required to exert forward force on the middle of the mast from the tips pressing on the stay wires. A force on the spreaders definitely not column compression. So the spreader tube and base must be much more robust. The spreader tube is probably wider in the for and aft direction than top to bottom to give this strength. That means that it is not so strong in holding its rigidity up and down as would be required if the stay were running free as opposed to being clamped. (If it is a round tube then no worries) Even given that I would suggest that the spreader probably has ample rigidity up and down without the wire being clamped. Only you can decide. You could give the spreader tip a little nudge with a boat hook to see if it will slide up or down the wire. I am guessing you will find it quiite rigid. If it does move and seems quite sloppy then you should worry more and perhaps get up in a bosuns chair to clamp the wires. But basically probably don't worry. Ask more experts to have a look. regards olewill

 

[DJE]

A couple of practical points. If the clamps aren't done up tight they will probably shake loose and the bolts will fall out. Also if the spreaders are clamped to the cap shrouds you can stand on them when climbing the mast without inducing droop and possibly bending the spreader. If I were you I would get up there and tighten the clamps.

 

[Bodach na mara]

I never fail to be amazed at the number of boats with spreaders that are not correctly set up. If there is only one set, they should slope slightly up to produce a pair of isosceles triangles, one to each side of the mast. Hence fixing the spreader to the wire at the point where the wire would reach the spreader rood if held down the line of the mast. Sometimes they are straight across, especially in gaff-riggers. They should NEVER (but often do) droop down! If they do, the tension forces in the rigging produce a tendency to slip even lower, leading to collapse of the mast.

Yes, they should be clamped to the wire.

 

[BarryT]

Look on the selden website for useful information on setting up masts