Forestay unwrapping

[Tranona]

Physics. Wire breaks, mast comes down into the cockpit.

The tens of thousands of boat owners who use furlers with forestays inside probably know this but does not seem to concern them. I wonder why?

Agree you need extra care when rigging and derigging regularly as in a trailer sailer, but on a yacht that has a halyard diverter to prevent wrap there really is not a problem.

The cause of unwrapping or breakage is the halyard wrap and use of force as many have described, not the fact that the wire stay is inside a foil.

 

[geem]

Physics. Wire breaks, mast comes down into the cockpit.

Why should it just because its inside an aluminium extrusion? Millions of boats have this set up with no problem. Why is your different?

 

[Neeves]

I found I got halyard wrap when the forestay kinked from stepping the mast on a trailer sailor. Riving at it aggressively only made the kink worse. My solution is to remove the furling system and fit a second forestay in the future. I can't see how a single steel wire that keeps the mast up enclosed in a foil can provide any peace of mind.

That's how most yachts with furlers are rigged, and owners have more expressed anguish anchoring that they do with furlers.

Jonathan

edit

apologies, I was a bit slow, crossed posts.

2nd edit - most masts that fall down do so in the sea and threaten to hole the yacht.

 

[dac31]

The foil is a solid section and the wire is flexible, it's very easy to cause the wire to kink, more so on a trailer sailor when the two lay horizontally on deck forming a very nice s curve in the wire. If this is hidden part is the only thing holding the mast up it's not a particularly redundant setup.

 

[geem]

The foil is a solid section and the wire is flexible, it's very easy to cause the wire to kink, more so on a trailer sailor when the two lay horizontally on deck forming a very nice s curve in the wire. If this is hidden part is the only thing holding the mast up it's not a particularly redundant setup.

I just don't see that. Surely the wire is inside the furler and when lying horizontal there isn't sufficient room in the extrusion to allow a kink. That is certainly the case with both our furlers. One is a Selden, the other a Profurl. The furlers are selected to suit the wire size and the furling sections sized accordingly

 

[Tranona]

The foil is a solid section and the wire is flexible, it's very easy to cause the wire to kink, more so on a trailer sailor when the two lay horizontally on deck forming a very nice s curve in the wire. If this is hidden part is the only thing holding the mast up it's not a particularly redundant setup.

Not sure you have a good grasp of how these things work. Do you think the designers are not aware of this and take steps to ensure the ire is kept straight in the foil even when not under tension. Many have intermediate bearings for exactly that purpose.

As in your earlier thread you seem to be overly concerned about problems that really don't exist in the mistaken belief that well tried rigging design and execution is somehow flawed. Given that your boat was designed and built by well respected people and proven by hundreds of owners over the last 40 years or so no need to change with your unproven ideas.

 

[penfold]

Physics. Wire breaks, mast comes down into the cockpit.

Generally not as there's a sail holding it up; often people keep their spinnaker halliard(and spare genoa halliard if present) on the pullpit which provides extra peace of mind. Then there's the shrouds; if there are twin lowers with a reasonable distance between the chainplates the forward pair will keep an otherwise unstressed rig upright.

 

[srm]

The foil is a solid section and the wire is flexible, it's very easy to cause the wire to kink, more so on a trailer sailor when the two lay horizontally on deck forming a very nice s curve in the wire. If this is hidden part is the only thing holding the mast up it's not a particularly redundant setup.

At the moment my forestay is disconnected and tied to the pulpit with furling drum just below deck level. With no tension on the stay foil and forestay have taken up a fair curve. This was done so that the forestay would not touch the travel hoist beam.
My point is that the foil is in fact capable of taking a fair amount of curvature without kinking the wire.

Incidentally, when buying the boat I replaced all standing rigging and upgraded the 7mm forestays to 8mm as they have to take unfair loads in use.

 

[Refueler]

Still a failure to my mind.

Agree .... but the word failure when we think of stays - usually brings to mind the stay parting ...

 

[Refueler]

Physics. Wire breaks, mast comes down into the cockpit.

Rubbish !

I speak from personal experience ...

Snapdagon 23.
Departing Bembridge - forestay came away from stemhead along with furling gear and genny ... literally flew 90 degs from masthead.
Guy with me used sheets and furling line to heave back ... while I used spinnaker halyard to create a temp forestay.
Mast only lost one spreader .... the side stays kept mast up.

Weather at time was F6 increasing.......

I do not say it could not happen ... but generally most boats the side stays could hold the mast.... as happened with mine and a number of other boats I know of.

 

[Refueler]

The foil is a solid section and the wire is flexible, it's very easy to cause the wire to kink, more so on a trailer sailor when the two lay horizontally on deck forming a very nice s curve in the wire. If this is hidden part is the only thing holding the mast up it's not a particularly redundant setup.

My mast goes up and down a lot ... the furler extrusion curves a lot often during such .... after years of this - I have yet to see evidence of your ideas ...

 

[sailoppopotamus]

The work of the devil, in my view. Replace it with a proper diverter fairlead fixed to the mast.

Out of curiosity, why do you (or @Tranona) think the diverter fairlead is a better solution?

One of my theories regarding what caused my problem is that the bushings in the diverter have failed, and pressure from the halyard on the disc imparted twisting forces on the forestay causing it to unravel even in the absence of a halyard wrap. I am thinking of seeking out replacement bearings for the diverter, which probably means buying a new diverter off Facnor as they don't seem to sell the bearings separately.

 

[capnsensible]

Halyard wrap = forestay birdcage. New forestay, unfortunately.

 

[srm]

Out of curiosity, why do you (or @Tranona) think the diverter fairlead is a better solution?

If you look at the geometry of halyard over a disc it is causing a near point load at 90 degrees to the forestay due to the halyard tension. An offset halyard via diverter or offset mast sheave is pulling the top swivel slightly out of line and imparting a smaller side force on the forestay for the same halyard tension.

The ideal set up would be to have the mast sheave giving the required lead angle for the halyard.

 

[LittleSister]

Out of curiosity, why do you (or @Tranona) think the diverter fairlead is a better solution?

Mainly because I seem to have read numerous tales of woe from people with such diverters, and can't recall any where the mast-mounted type was at fault. But also because the forestay mounted ones just don't seem mechanically 'right' to me - seemingly only likely to work if everything goes right, and eventually it won't.

It does require care to place the mast-mounted diverter in position in relation to the top of the foil to give the appropriate angle of pull - not too much side pull, but certainly not too little.

 

[sailoppopotamus]

Thanks for the explanation. I agree that the force distribution with a fairlead diverter looks more reasonable. After the wrap incident two years ago I had a diverter installed by a rigger, who I realize now didn't know what he was doing -- the angle was too great and I just couldn't get anywhere close to the required luff tension. He didn't remove the disc. Subsequently I rerouted the halyard to the original configuration and, haven't had any serious wraps.

Anyway, the forestay is off the boat now:



Two further questions:

1. In shopping for a new stay, are there any disadvantages other than cost in going for dyform/compacted strand rigging over plain 316 wire? Assuming I can even find it in Athens, that is.
2. Would perhaps a fairlead + diverter disc combine the best of both worlds? The idea is to place a fairlead such that the halyard forms an angle of 10-15% with respect to the forestay, and just clears the disc. The fairlead would ensure the genoa halyard doesn't tangle, and the disc would be there to ensure that the spinnaker halyard also stays out of the way. Incidentally, does it have to be a fairlead or would a block be a better lower-friction solution?

 

[Tranona]

This is an example of correct use of a Selden diverter. (not my boat)

 

[dac31]

Thanks for the explanation. I agree that the force distribution with a fairlead diverter looks more reasonable. After the wrap incident two years ago I had a diverter installed by a rigger, who I realize now didn't know what he was doing -- the angle was too great and I just couldn't get anywhere close to the required luff tension. He didn't remove the disc. Subsequently I rerouted the halyard to the original configuration and, haven't had any serious wraps.

Anyway, the forestay is off the boat now:

View attachment 157772

Two further questions:

1. In shopping for a new stay, are there any disadvantages other than cost in going for dyform/compacted strand rigging over plain 316 wire? Assuming I can even find it in Athens, that is.
2. Would perhaps a fairlead + diverter disc combine the best of both worlds? The idea is to place a fairlead such that the halyard forms an angle of 10-15% with respect to the forestay, and just clears the disc. The fairlead would ensure the genoa halyard doesn't tangle, and the disc would be there to ensure that the spinnaker halyard also stays out of the way. Incidentally, does it have to be a fairlead or would a block be a better lower-friction solution?

Looks like you went for the double whammy on that one! I can only say my forestay had half the kink complexity of yours, but enough enough to cause the foil to jam and the halyard to wrap. One other thought I had actually was that when it happened to me sometimes adding more backstay tension helped so possibly a contributing factor to your issue.

 

[Bilgediver]

The forestay is obviously getting replaced. My question is, what could have caused such a failure? These things usually fail at the terminals, no?

I would recommend obtaining a forestay where the lay of the wire is the opposite direction and this will help prevent birdcaging . A goog rigging person should be able to supply right or left hand. Maybe even switching to Dyform might get the opposite lay plus a smoother outer surface.

 

[sailoppopotamus]

Just a little update to this old thread. I replaced my forestay, and the top swivel with a used one that I "rebuilt" (changed ball bearings, not races, which I couldn't easily source). I went with compacted strand for the replacement forestay. Got through circa 700 nm, most of which in healthy (yet not savage) meltemi winds, no problem at all. Then suddenly one day, in barely a F2, I couldn't unfurl the genoa. Noticed that halyard wrapping around the forestay, tensioned it a bit, unfurled the sail with no problem.

A few sails later (some of which in F5-F6), I weigh anchor with my reasonably-fit-yet-definitely-not-muscular cousin in a F2. I tell him to pull on the sheet to unfurl the genoa. My attention drifts elsewhere, until I notice him really struggling to unfurl the sail. I tell him to stop putting all his weight on the sheet, there's clearly some sort of issue. I slacken the halyard just a bit, and the sail unfurls fine. A couple of sails later, I simply can't get the sail to unfurl at all. I try all possible halyard tensions, from reasonably firm to completely slack, the halyard would just wrap around the forestay no matter what.

I went up the mast to investigate the issue, only to find that my brand new forestay has suffered from this unwrapping/birdcaging as well. So yet again, I need a new forestay! More crucially, I've lost all faith in my furling system and I'm probably looking at getting a new Facnor LX system professionally installed by the local distributor, at a fair yet still eye-watering cost. I tried sorting this out in a DIY manner in line with the spirit of this forum and boat ownership, but I'm pretty much acknowledging defeat at this stage.

I should've fitted a halyard diverter - I didn't. The sail furled/unfurled with no problems after replacing the forestay/upper swivel, with the aid of the Facnor halyard deflector. So I was perhaps lulled into a false sense of safety, thinking that I didn't need a diverter after all. I went through 700nm in breezy conditions with everything working perfectly, until it didn't.

I would recommend obtaining a forestay where the lay of the wire is the opposite direction and this will help prevent birdcaging . A goog rigging person should be able to supply right or left hand. Maybe even switching to Dyform might get the opposite lay plus a smoother outer surface.

And here we get to the crux of my post. Initially I thought this was a very good idea. But I didn't anticipate that halyard wrap might occur when *unfurling* the genoa. It never occured to me that halyard wrap might occur when I told my cousin to pull on the sheet to unfurl the sail. In my opinion, the lay of the halyard should be such that 'birdcaging'/unravelling is more likely when furling the sail, rather than unfurling. You have to pick one -- you'll either be more likely to unlay the forestay when unfurling or furling the sail. In my (definitely non-expert) view, it's better to be in a position where unlaying the forestay is likely to occur when furling rather than unfurling. My thinking is that you can always control the furling of the sail via the furling line. If you get a halyard wrap, you just stop furling, unfurl the whole sail and drop. But with unfurling, you're at the mercy of the wind -- if it's blowing ,your sail will try to unfurl, and if a halyard wrap does occur, the force of the wind might just be enough to unravel your forestay. In all likelihood, this did not happen in my case, it was pure muscle force that did it in benign conditions. But it could easily have been a strong wind instead.

This is a tale involving no winches. As far as I can tell, my cousin (through no fault of his own, it was his third trip on a boat) managed to unravel the forestay by just pulling on the sheets vigorously. It never occurred to me that *unfurling* the sail might damage the forestay, or indeed that a forestay could be defeated by muscle force alone.

To summarise:
1. A 6mm forestay can be fatally weaked by muscle power alone, no need to involve winches.

2. Halyard wrap can occur when unfurling a genoa, not just when furling.

3. In an ideal world, the forestay lay should be such that unravelling is a risk when furling a sail, i.e. halyard wraps when furling rather than unfurling threaten the stay. You can control the force applied to the furling line better than you can control the force on the sheet when unfurling a sail in breezy conditions.

I realize that I'm probably overthinking this, and that a well-installed system won't have to contend with these issues. I certainly hope that a new roller furler installed by an experienced rigger will put my mind at ease. In any case, this is my experience, and these are my thoughts, and hopefully at least one pearson will find them useful.