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Floppy spreaders

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Post Options Post Options   Quote snowleopard Quote  Post ReplyReply Direct Link To This Post Topic: Floppy spreaders
    Posted: 11 Mar 20 at 5:29pm
On my 1980s 420, the spreaders are loosely attached at the mast and the shrouds pass through sizeable holes in the spreader tips. This means that the spreaders are free to swing fore and aft and up and down the shrouds. When the rig is set up tight, the spreaders are roughly horizontal and don't deflect the shrouds.

I am more accustomed to rigging offshore boats where the spreaders are fixed and substantially deflect the shrouds.

What purpose do these dinghy spreaders serve? I can see they would help a little in reducing sideways mast bend but they wouldn't have much effect till the mast was some distance out of column.

Any thoughts on how best to set them up?
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Sam.Spoons View Drop Down
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:12pm
Dinghy spreaders are usually rigidly attached to the mast bracket with the angles (up/down and fore/aft) fixed. The shroud passes through a hole and is not usually locked off but there should be at least a few degrees deflection which minimises movement.

As with a bigger boat the purpose is to give some control over sideways and fore/aft bend (including pre-bending the mast aft). Even with a floppy rig like some single handers they limit bend when the rig is powered up.

But who knows what has been done to an older boat.......


Edited by Sam.Spoons - 11 Mar 20 at 9:16pm
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Post Options Post Options   Quote Granite Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:17pm
I have seen floppy spreaders on a few older masts, and would agree that they are not too good for controlling the mast bend. Most dinghys have fixed spreaders that do deflect the shrouds a reasonable ammount. If when on the water it is looking wrong with the sail you have I would see if you can work out a way of locking the spreaders in some way. Unfortunatly spreaders and fittings are quite pricy so replacement could cost. The 420 class site, or some sailmakers are likely to have a list of settings you could use.
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:38pm
Duck tape will fix them...

Used to have floppy spreaders on the firefly. The lack of rig tension meant that the leeward spreader would go forward on a run, so not putting a whacking great dent in the sail.

Not sure I can see it working with 420 rig tension or spinnaker.
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 11:54pm
The trend on the Blaze a few years ago, at least for those with M7 tin rigs, was to have floppy shrouds and swinging spreaders where the leeward spreader would swing forward to facilitate sailing 'by the lee' downwind. The carbon mast is usually setup with more tension and swinging spreaders are not recommended.
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Post Options Post Options   Quote giraffe Quote  Post ReplyReply Direct Link To This Post Posted: 12 Mar 20 at 8:55pm
National 12s have swinging spreaders, it is important to have some form of restraint so that they cannot both swing forwards at the same time as the mast will invert.

The reason for having this set up is that it avoids the spreader poking into the mainsail when sailing on a run. This gives an improved sail shape. It also allows the boom to be set up square to the mast as the shroud is eased. If you are not easing the shroud you won’t get the boom past 80 degrees and the spreader will likely be at a similar angle to the boom.

Never seen it done on a spinnaker boat.
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 12 Mar 20 at 10:48pm
I'd say it will only work on boats with low or zero rig tension, so nothing with a spinnaker or trapeze. The windward spreader will swing aft as the shroud tensions up, the leeward spreader, on the Blaze at least, can swing forward to a preset angle as the leeward shroud is floppy. I'm not sure how it works on a N12 as no rig tension may mean a floppy jib luff? The Stars deal with the problem by having adjustable shrouds and runners to manage rig tension.
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Post Options Post Options   Quote Riv Quote  Post ReplyReply Direct Link To This Post Posted: 13 Mar 20 at 9:27am
Had a similar arrangement on a very old 420 as well.( Honour Marine) I remember trying to add rig tension to it and noticing the hull distorting around the mast step, which was 50mm deep fore and aft moulding with the step a slot cut into it so under it was only about 35mm. I expect that rig tension ws not a thing in the 420s at the time of production. We took the spreaders off and it didn't make any difference. There was no tackle or highfield lever we did the same as the Laser 2, pulling the forestay and tying off the jib halyard and letting the forestay go.
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Post Options Post Options   Quote Sussex Lad Quote  Post ReplyReply Direct Link To This Post Posted: 13 Mar 20 at 12:45pm
Self amalgamating tape does a good job on the spreader tips. It looks neat and helps protect the sails when they chaff on the tips. The tape remains flexible enough to allow adjustment.

....of course, gaffer tape will do but it's not good for the image  Wink
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Post Options Post Options   Quote giraffe Quote  Post ReplyReply Direct Link To This Post Posted: 13 Mar 20 at 6:05pm
No problem with a floppy jib luff downwind on a n12 . In fact much faster. Windward shroud is tight and spreader poking into mast bends the top of it to windward powering up the rig. Shrouds lengths are generally adjustable so rig under tension upwind but not off wind

Edited by giraffe - 13 Mar 20 at 6:05pm
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