Storm jibs

[MainlySteam]

I go along with a high modulus rope luff line attached to a similar material halyard as being sufficient and is probably the way I would go if I did it again.

Looking at it from the reverse viewpoint we have a permanent inner wire forestay to the second (upper) spreaders for setting small and storm jibs but it is not set up as drum tight when unused because even on a heavily rigged cruising vessel it will set the mast forward at the upper spreaders. The reverse bit is that when in use it is pulled up tight with high modulus rope, not wire, runners taken aft.

I suspect that if a rope runner (and rope running backstays are very common) can pull a wire forestay tight then a high modulus rope luff line and halyard on a jib can be tightened enough and without problem by whatever means the rig makes available.

It also does away with the maintenance and the rigging time of hanks (including avoiding finding that one has hanked one round back to front when go to hoist /forums/images/icons/blush.gif).

John

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[ChrisE]

Oh-ee, I got the wrong end of the stick, again!



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[doris]

Re: Inner forestay

I absolutely agree with Chris. Take the inner stay to the top of the mast and then you can use a existing halyard. Also if you don't need runners at the mom why create problems. Mind you if have in line spreaders you should have anti-panters anyway!! An adjustable backstay makes life a lot easier when putting on the inner stay.

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[LadyInBed]

When talking to Kemp’s, they offered a storm jib with a built in wire luff that could be tensioned by the spinnaker halyard. Instead of trying to set it flying, could it be set using ties as you would use elastic bands on a spinnaker?

An alternative might be to have the storm jib hanked / shackled on to the wire and be tensioned by the spinnaker halyard as above but with a block at the top of the wire luff to facilitate hoisting the storm jib.
Would it work?


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[qsiv]

Can't see why not! Just need to take care over kinks, and rust stains when stowed.

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[MainlySteam]

Re: Inner forestay

But remember that sagging of the forestay is dependant upon the tension in it. So, if you take the inner forestay to the masthead you increase the column loads on the mast greatly if you want both it and the forward stay to be as tight as the forward stay was before. For example, if the forestay load was 2T before then it will have to be maintained at 2T if more sagging is to be avoided, plus the inner stay to the masthead will be approximately the same. So, if the inner forestay runs just inside the main forestay the compression load in the mast from the forestays will be doubled if the same forestay tension is wanted. As the foot of the inner stay is moved back towards the mast the compression loads in the mast increase (the vertical contribution from the inner stay varies as the sine of the angle with the deck).

That is if you have the inner masthead forestay just aft of the main forestay you will double the mast compression loads. As the inner stay is moved back you will more than double the mast compression loads - all assuming that one does not want to suffer a performance trade off on the wind of greater genoa luff sag than before. The tension of the inner stay can be run lower than that in the forestay in order to lessen the increased loads but that will have to be substantially so if any great reduction is wanted.

The only way around this I know of is to have the unused forestay loosened when not in use, suffer greater forestay sag on the inner stay (which only reduces the added mast compression, not alleviates it), or have a rig that is designed for the increased compression load and that may not be the case if modifications to an existing rig are made.

Of course these things happen with a short inner forestay too, but the effect is greatly reduced because of the lesser tension required to avoid sag and the much shorter length of the mast column affected.

John

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[uforea]

I think you need to be careful about using the spinnaker halliard in this way. On my boat, and others I've looked at. the halliard goes through a swivel block attached to the masthead crane. I don't think that this fitting would take anything like 2 tons load. Use of this halliard should be for hoisting only and not to tension the luff of the sail.
Ted.

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[LadyInBed]

My genoa and spinnaker blocks are side by side and identical.
I reckon that the tension I put on the spinnaker halyard would be the same as that on the genoa.
They both look pretty beefy to me.


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[poter]

Re: Inner forestay

just a question... if you set up an inner forestay, say on a permanat basis, how do you get over the problem of tacking with your Genoa?

Surely you will get some damage over time, or am I missing something?

poter.

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[MainlySteam]

Re: Inner forestay

If the inner forestay is set well back from the bow, say from the upper spreaders and parallel with the forestay, then there is not much problem. With a big genoa in very light weather the bowlines attaching the sheets to the clew may catch on the inner forestay, however that is not a problem when there is any wind. Doesn't seem to cause any damage with the sail dragging across the stay when tacking.

On vessels with the inner forestay set well forward, and permanently rigged (as they usually are) with only a smallish gap between them, then in my view the only relatively simple way when the outer one is in use is to furl the genoa before tacking and then unfurl it when the bow has passed through the wind. I personally would not consider such a close arrangement on any but a very large yacht for which tacking is usually an infrequent manoeuvre.

If the extra forestay is set up to the bow, it is best, in my view, to be attached at the deck alongside (but spaced away from) the main forestay having the genoa so that its presence is of no consequence to tacking the genoa. However, I see this as being messy and as not being a very sensible solution unless one wants to get into setting two foresails when downwind but for that there are good options appearing such as asymmetrical sails set on line furlers. I have not seen two forestays right at the bow when the genoa is on a furler and the drum obviously requiring the other stay to be well spaced sideways from it (but the type of boat with such a compromised arrangement would not be one with which I would normally be associated). If the purpose of the stay is to set a smaller or storm jib, then it would seem best to me to rig the inner forestay further back to the mast bringing its centre of effort back plus keeping one off the pointy bit of the bow when one has to set it (presumably in uncalm seas) as well as reducing the compression loads in the mast.

Frankly, I see no merit whatsoever to rigging the second forestay at the bow as some are promoting - seems to me fraught with problems and compromises not appropriate to any well fitted yacht.

John


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