Spreaders... are they necessary?

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Spreaders... are they necessary?

Postby hnash53 » Fri Sep 16, 2016 8:28 pm

I've had my DSII for a month/6 weeks now, and was looking at the spreaders. They don't seem to "spread" the side stays hardly at all And so, I was wondering if they are really doing anything necessary for my boat.

When sailing and running, the sail is pressed up against the stays some.

I just don't see the necessity of having them.

Can someone enlighten me?

Thanks.
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Re: Spreaders... are they necessary?

Postby TIM WEBB » Sat Sep 17, 2016 2:03 am

Most sailboats with a stayed mast use spreaders. They help provide the support the mast needs to stay up and straight. If you feel that yours are not providing this benefit, I would take a good look at your rig tension, and/or whether or not your spreaders are the correct length. If they are not, the correct ones can be had from drmarine.com.
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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Re: Spreaders... are they necessary?

Postby hnash53 » Sat Sep 17, 2016 11:39 am

TIM WEBB wrote:Most sailboats with a stayed mast use spreaders. They help provide the support the mast needs to stay up and straight. If you feel that yours are not providing this benefit, I would take a good look at your rig tension, and/or whether or not your spreaders are the correct length. If they are not, the correct ones can be had from drmarine.com.


It just looks to me like they don't "spread" the stays much. In other words, the wires don't appear to be "spread" hardly at all. The mast is well supported, though. It looks like if I removed the spreaders the angle of the wires extending from the hull to the mast would not be changed at all. But I don't think there is anything amiss in terms of mast support.

Would it make any difference if I removed them?
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Re: Spreaders... are they necessary?

Postby Baysailer » Sat Sep 17, 2016 12:21 pm

Racers will probably chime in but I think you could sail minus the spreaders with no ill effects. Some sailboats do not use spreaders (buccaneer 18 for one). My spreaders, like yours, are in line with the stay. There is no poke. The tuning guides from North, Dieball and Doyle explain spreader tuning pretty well and all describe longer spreaders than mine and fixed (mine are free swinging). The guides say spreaders directly affect mast bend. I would have changed out for longer and more tunable spreaders but my stays are fixed length with no adjusters so I Ieft well enough alone. Even with the way mine are I think they prevent the center of the mast from bending to windward.
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Re: Spreaders... are they necessary?

Postby GreenLake » Sat Sep 17, 2016 2:47 pm

Well, if you consult the literature, you find that "spreaders...are put in to diminish the free length of the mast tube." Reducing this free length, dramatically reduces the required stiffness of the mast section. Or, to translate this to your case, leaving out the spreaders does not support the mast as well, and it therefore should be stiffer.

If you think that the mast on a DS is overdimensioned for the loads that you can out on it, then you could see whether you can get away without spreaders.

The limit for the load that you design a mast (including shrouds and spreaders) is independent of actual wind strength or sail size, because at some point, the boat will simply capsize. That's why heavy crew will place higher loads - when the hike out on your boat, you'll need higher forces from wind and sail to capsize it.

Having a mast keel stepped, also allows it to be thinner, compared to a deck stepped mast. So, if you first cut down the mast to add a tabernacle and then remove the spreaders, at some point you are beginning to chip away at the safety factors that the designer took into account when selecting the kind of mast extrusion (and dimensions) to use.
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Re: Spreaders... are they necessary?

Postby KingsTransom » Sat Sep 17, 2016 9:59 pm

I would not remove the spreaders. To do so would change the geometry of the members that provide support and rigidity to the mast. The spreaders change the angle of the tension the shrouds exert on the mast. Removing the spreaders with increase the amount of force pulling the mast downward, and decrease the force pulling sideways, creating forces outside the design specs of the boat. The spreaders also move the shrouds out of the path you walk to go forward.

How long are your spreaders? If you have anything near stock (~21"), then removing them will leave you with far more wire than you can take up with the adjusters.
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