Shortening the forestay

[SimonD]

Just concluded a depressing conversation with my rigger and would appreciate me learned friends' views.

It appears that at some time the previous owner of my boat shortened the roller reefing foil. This has resulted in the top bearing running on the forestay which in turn has led to the forestay 'unravelling' at the top. The rigger's has suggested two options: splicing in a new section of foil (fiddly and therefore expensive) or shortening the forestay to match the foil length and adding a 4 to 6 inch strop at the bottom to make up the missing length. This sounds fine in principle except that it lifts the drum (and hence sail) a further 4 to 6 inches off the deck.

Does anyone see any problems with this solution. In particular, will the genoa sheets still lead back at a reasonable angle etc.

 

[vyv_cox]

If you really need to shorten the forestay, why not add the strop at the top. In this way the sheet angle will not change at all. But will the luff of the sail accommodate this shortening? If no, then just shorten the sail and kill two birds with one stone.

The main cause of forestay unravelling in my experience is that the halyard to forestay angle is too small. When furling the sail the halyard wraps itself around the forestay instead of applying a tangential force to the bearing on the foil. Usual solution is to run the halyard through a bullseye fairlead lower down the mast. I assume that the bearing does not lift right off the foil, or you would not be able to lower the sail. Maybe adding a bullseye will solve the problem.

 

[tony_brighton]

Raising the forestay on a strop would raise the centre of effort of the sail- which may affect balance (both of the boat and the sail trim); depending how sensitive your boat is. On the plus side it may improve visibility.

 

[Guest]

Bit puzzled about what your rigger has said. On both my boats the top bearing has run on the wire (as it was designed to do) and without problem. If you have managed to un-lay some stainless wire rope, then the force required would be generated by the bearing seizing, not just by it running on the wire. Recommend you investigate further.
Dont ignore the route of replacing the forestay. It is easily done as a diy job using stalok or norseman fittings, and it is likely to be cheaper than the combination of a strop and sail alterations. If you try this, then shop around for your wire and fittings. Riggers seem to think that rrp = compulsory selling price.

 

[Miker]

That\'s how I lost my mast

My boat when new was incorrectly rigged by the supplier, now defunct. The foil was shortened to meet the length of the genoa with the swivel being too far below the halyard restrainer. The result was that the halyard twisted around the forestay when the genoa was wound and unwound and put a twisting motion on the forestay. Finally one good tug to wind in the genoa snapped the forestay and brought everything crashing down on top of me. Luckily I was just outside of the marina and was quickly towed in by the RNLI in front of a large watching crowd on the shore.
The rigger replaced the forestay and fitted a longer foil to bring the swivel near to the restrainer and attached the genoa to the swivel by a rope strop. This happened about fout years ago. since then, genoa has wound in and out without any difficulty.
I also quickly went out and bought an emergency aerial (I now also have a back-up hand held VHF) and bolt cutters as if it had happened the previous week in strong winds I could have been in trouble.
My advice would also be to replace the whole forestay.

 

[SimonD]

Re: That\'s how I lost my mast

Many thanks for the helpful comments. I shall certainly replace the forestay, but I am also confused by the rigger's comments. He says the top bearing should "run on the swage, not on the wire." I'll take another look at it.
The idea that the swivel is too far below the halyard and hence at too shallow an angle to exert sufficient turning moment makes sense. Looking at various manufacturers' websites, this seems to be a recognised risk (referred to as "halyard wrap"). The cure is some sort of block above the swivel to hold the halyard off; I can see that a fairlead would do the same job.
Unless a second look suggests otherwise, I think I'll replace the forestay, check the swivel is free and adjust the halyard angle. All much cheaper than the £250 quoted! Thanks again.

 

[Guest]

Re: Check your Genoa Halyar

After you sort out the weared forestay problem, check your geona halyard tension in the future.

In the past, someone told me that the geona halyard should always be losen and only use the back stay to control the forestay and geona tension. As a result of insufficient geona halyard tension :
a) the halyard easily got wrap around the forestay when furling/unfurl the sail,
b) when the foil turns the upper bearing is pressed on the forestay and wearing both the bearing and the forestay.

I now tighten the tension on the halyard before furling / unfurling the geona and the problem solved. I also apply W40 on the head swirl unit everytime I climb the mast to check the fittings.

Hope that it can help you to prevent future problems on the furling gears.