Unusual shrouds

[Bejasus]

anyone know why there would be 2 shroud wires attached to mainmast between spreaders and masthead? Both are attached to eyebolts on the deck just inside the toerails and via a kicker type pulley arrangement. I haven't seen this before, hence the quuestion. However I would take a guess at their being there to lead back to winches to induce some kind of mastbend for upwind sailing. This is purely speculation on my part. No way possible to minduce anything without the use of a winch. Ideas?

 

[mariog]

Running backstays, the windward one should be tensioned and leeward released on a beat. Presumably your boat is a fractional rig with aft spreaders, and release both on a run

 

[William_H]

Yes as mariog says it sounds like running backstays. If it is a fractional rig ie the forestay attaches to the mast below the mast head then when you pull hard on the backstay which is attached to the mast head you do put tension on the forestay but also put a bend in the mast. That can be good for reducing mainsail camber but means less tension on theforestay.
You want the forestay bar tight (straight) because any sagging to leeward of the middle of the forestay feeds cloth into the middle of the luff giving more camber just when you need less camber. This ccan be overcome with a hollow cut luff but then you can't get so much camber for light winds.

If you attach a backstay right at the point of attachment of the forestay you can crank on a lot of tension without bending the mast. However that kind of backstay will foul the mainsail. So 2 running backstays are used which can be released on tacking or gybing to allow the sail to swing across. ie you only tension the windward running backstay.
Running backstays often have an adjustable branch which attaches to the mast further down ie near the spreaders. This is to provide aft pull on the mast at this point to maintain the mast straight (therefore in perfect column which is strongest) or with a desired degree of bend while well supported.
For any sort of short handed or tight area sailing the running backstaysare a real problem. you need a crew person dedicated to operating the runners. I took them off my boat when I bought it. The mast can be controlled by aft swept spreaders in lieu of runners. However on long legs in rough water with a flexible mast they can improve control markedly. olewill

 

[Bejasus]

[ QUOTE ]
Presumably your boat is a fractional rig with aft spreaders, and release both on a run

[/ QUOTE ]

actually they are not backstays in the normal sense of the word, and no aft swept spreader either.

Ketch rig and these lines come almost straight down to port & starboard rails, although they are attached to the mast at the same height as the inner forestay is connected, so I can only guess that as you both suggest, they are for tensioning when using that sail, but to induce more support on the windward side rather than to create bend in the mast??

 

[mariog]

From your photo I can see that they look more like checkstays and they should be tensioned especially when the inner (smaller) forestay is in use to tension the middle of the mast and straighten it more, by doing so will prevent the mast from pumpimg in heavy weather when falling of the waves.

 

[Bejasus]

thanks guys.

mariog, that confirms my thinkng also. I had just never come across them before and the previous owner never used them.

 

[Chris_Robb]

Cutter Rig

You have a cutter rig - so the running back stays are essential in heavy weather to counter the pull of the inner forestay, which if not countered would result in a bust mast. Use to keep the inner forestay tight when on the wind, and in heavy seas, and wind to stop the mast panting. Probably essential to us above force 7.

 

[Bejasus]

Re: Cutter Rig

so tighten on the windward side then when using the inner forestay. Cheers Chris

 

[yoda]

In addition to the other advice I would expect the wires to have a second fixing eye further aft to provide a better lead before applying tension, the forward eye being for storage when not in use or on the leeward side. these are very important if you don't want to end up with a broken mast.

Yoda

 

[Bejasus]

I will check for fittings further aft but havent noticed them yet, but the boat is new to us and our first ketch. Not back there for another couple of weeks, when I have to move it to the Tampa area of Florida.