One for the riggers

[Overandunder]

Evening. When I bought my boat it wasn't local to me and at purchase its mast had been removed so all and sundry could be loaded on a truck.

This meant I didn't get to check the rig or make detailed notes. I've since worked it out, mostly. Its simple enough - single (aft swept) spreader 7/8 fractional rig with a single cap shroud, single lower.

The bit I'm unsure about is where the cap shroud meets the spreader end. At this point the shroud passes through a bracket with a single allen bolt which creates a clamp - so my question is how tight should this be ? The shroud doesn't make an even angle either side of the spreader (the spreader being a solid aluminium bar that passes right through the mast). Any thoughts / guidance appreciated on how to set these up would be much appreciated.

 

[Sea Change]

Ideally you want the spreader to exactly bisect the angle of the cap shroud, i.e point upwards slightly.
I'm not familiar with the spreaders as you describe them and I presume there is no adjustment possible, if it's a single piece? Perhaps it got bent in transit?

 

[Overandunder]

Ideally you want the spreader to exactly bisect the angle of the cap shroud, i.e point upwards slightly.
I'm not familiar with the spreaders as you describe them and I presume there is no adjustment possible, if it's a single piece? Perhaps it got bent in transit?

There doesn't appear to be a way to change the shroud angle above / below the spreader, though in fairness there isn't a huge difference in this. The spreader system is made of 3 parts - 2 ally straight wings either side with a solid ally bar to link them, this is manufactured with a deliberate curve to it as it passes through the mast (to create the sweep).

Its the spreader ends I'm unsure about - should the clamps be tight before the mast goes up - or left slack so the cap shroud can 'self adjust' the angle as it were ??

 

[Sea Change]

I would leave them with a bit of play while getting the mast up and the rig tuned, then go up and tighten them a bit.
But I'm not a rigger...

 

[William_H]

There is no indication of what sort of boator size but I would guess that it is relatively small like less than 25 ft. The failure of rig designer to arrange spreaders to tilt up warsd indicates no concern re compression on spreaders. Not a criticism just that speaders may easily be able to cope with end pressure from cap shroud that is not in line with the spreader. If OP is concerned he may be able to bend the central bar to give some few degrees of up tilt. IMHO the end attachment of stay to spreader end can be left free to slide although locking the end screw after tensioning the rig may provide more support to spreader. Mine on my 21fter have always been sliding attachment.
What is important in this type of rig is aft sweep of the spreaders. This provides pressure middle of the mast forward against the aft pull of intermediate stays at mast middle so providing support in the fore and aft direction of middle of mast. Not just swept aft to meet the stay but to provide pressure. Aft sweep should mean a little middle forward bend top mast with back stay loose. Load up back stay should then provide more mast bend for stronger winds. I had a mast crumple when a spreader aft sweep failed and it swung forward (rivet failure). (now more robust spreaders. ol'will

 

[john_morris_uk]

You should fix the shroud in the spreader before stepping the mast. The normal technique for determining where to fix the shroud in the spreader is with the mast down and rigging slack, to bring the shroud to the root of the spreader and mark the wire. Then take the shroud out to the spreader end and fix the wire at the mark. (As taught me by a rigger). Easy peasy.

If you can’t achieve the right place to fix the wire then there will be some odd strains on the spreader as it won’t just be in compression.

 

[bignick]

Evening. When I bought my boat it wasn't local to me and at purchase its mast had been removed so all and sundry could be loaded on a truck.

This meant I didn't get to check the rig or make detailed notes. I've since worked it out, mostly. Its simple enough - single (aft swept) spreader 7/8 fractional rig with a single cap shroud, single lower.

The bit I'm unsure about is where the cap shroud meets the spreader end. At this point the shroud passes through a bracket with a single allen bolt which creates a clamp - so my question is how tight should this be ? The shroud doesn't make an even angle either side of the spreader (the spreader being a solid aluminium bar that passes right through the mast). Any thoughts / guidance appreciated on how to set these up would be much appreciated.

Have a look at p18 of this:
https://support.seldenmast.com/files/1605537330/595-540-E.pdf

Selden say that the cap should be tight enough that you can stand on the spreader wothout the tip sliding on the shroud.

 

[Neeves]

A photo is worth a thousand words.

Jonathan

 

[Neeves]

Have a look at p18 of this:
https://support.seldenmast.com/files/1605537330/595-540-E.pdf

Selden say that the cap should be tight enough that you can stand on the spreader wothout the tip sliding on the shroud.

That must be a function of yacht size and the size of the individual standing on the spreader

Jonathan

 

[bignick]

That must be a function of yacht size and the size of the individual standing on the spreader

Jonathan

Logically, yes.
However, the Selden guide doesn’t make any such distinction…

 

[Chiara’s slave]

That must be a function of yacht size and the size of the individual standing on the spreader

Jonathan

True. I can stand on the spreaders on our XOD, but there are quite a number of gents sailing in the fleet for whom that would definitely not be recommended. Notoriously, one of them is 20% heavier than mine and Mrs C’s combined weight, and neither of us is a midget.

 

[Overandunder]

There is no indication of what sort of boator size but I would guess that it is relatively small like less than 25 ft. The failure of rig designer to arrange spreaders to tilt up warsd indicates no concern re compression on spreaders. Not a criticism just that speaders may easily be able to cope with end pressure from cap shroud that is not in line with the spreader. If OP is concerned he may be able to bend the central bar to give some few degrees of up tilt. IMHO the end attachment of stay to spreader end can be left free to slide although locking the end screw after tensioning the rig may provide more support to spreader. Mine on my 21fter have always been sliding attachment.
What is important in this type of rig is aft sweep of the spreaders. This provides pressure middle of the mast forward against the aft pull of intermediate stays at mast middle so providing support in the fore and aft direction of middle of mast. Not just swept aft to meet the stay but to provide pressure. Aft sweep should mean a little middle forward bend top mast with back stay loose. Load up back stay should then provide more mast bend for stronger winds. I had a mast crumple when a spreader aft sweep failed and it swung forward (rivet failure). (now more robust spreaders. ol'will

She's a Jeanneau SO 8.8 metre. Simple rig designed for cost and ease of handling I assume.

 

[Overandunder]

A photo is worth a thousand words.

Jonathan

Absolutely. Not my example - but a close enough design ;

 

[Overandunder]

You should fix the shroud in the spreader before stepping the mast. The normal technique for determining where to fix the shroud in the spreader is with the mast down and rigging slack, to bring the shroud to the root of the spreader and mark the wire. Then take the shroud out to the spreader end and fix the wire at the mark. (As taught me by a rigger). Easy peasy.

If you can’t achieve the right place to fix the wire then there will be some odd strains on the spreader as it won’t just be in compression.

Great tip - thanks