Friday, November 15, 2013

Broken forestay

On our way south from the Bay of St. Vincent we were beating into 20 knot winds with squalls when all of a sudden there was a terrific bang. Our first thought was that we had hit an under-water object, but then I looked up to see the roller furling foil and jib swinging crazily off to one side and I realized that our forestay had broken.

We quickly adjusted the wind vane to run off downwind and I rigged a spinnaker halyard to steady the mast. We were unable to furl the jib at first, so I tried to drop it, again without success, because the jib halyard was the only thing holding up the foil and trying to lower the sail just lowered everything. So instead we tightened the halyard and rolled in the sail using a winch to assist.

On closer inspection, the roller furler drum unit was bent out of true and the bearings and seals wrecked, the Spinlock clutch holding the jib halyard shattered, and the wind indicator at the masthead was destroyed. We motored with the 2-reefed main to steady us into a nearby harbour, choosing our destination so as to have a comfortable angle to the swells to minimize the motion of on the damaged rig. After lunch Rani hoisted me to the masthead to inspect and make repairs if possible. From the top of the mast I noticed that the halyard anti-wrap unit had disappeared when the stay broke. The stay had broken off just inside the swage that was flush with this unit. Far worse, I noted that the top portion of the mast is rippled from the shock of break when the back stay pulled back on the mast. I added a line to secure the sail directly to the forestay tang and reduce the chafe on the jib halyard. I also duct taped the furled jib to the inner stay to dampen its swinging. I should have run a line in a spiral all the way down the length of the jib to tie it off to the spinnaker halyard as this would have steadied things a lot, but I only thought of this once back on deck.

I am not sure how much the top section of the mast has been weakened. I think we can replace the forestay, repair the furler, and make our way south to New Zealand under staysail and reefed main. When in NZ we should be able to repair the mast, hopefully with a sleeved in top section only. The only question is can we fly a jib, too, on the way south or is the weakened mast portion too damaged for that? The ripples in this mast section are maybe 1/8 inch - 1/4 inch out of true, spread out evenly over the column at intervals of a foot or less, with no visible cracks. The mast section does not appear to be bent port or starboard.

People here have been very helpful, with advice and assistance from friends on Akimbo, Papillon, and Sir Francis in the last two days. We now have a contact for a shop here that sells rigging materials and can hopefully make us a new forestay. The main issue is that our current rig is 9/32 inch where the French use only Metric wire. We currently plan to replace the forestay with larger 8mm wire and to use a Norseman fitting on the bottom and maybe the top also. The current stay is 9/32 and is not available here so we would need to replace the old 9/32 Norseman on the bottom of the stay with a new metric one, too. And then this might necessitate replacing the turnbuckle which is an English Gibb unit and may not be metric threaded either and hence may not interface with a metric Norseman. If this is the case it may be cheaper and easier to have order a 9/32 forestay in New Zealand assuming the NZ riggers have access to such stuff.

We should be ok to make the trip between the two of us assuming I can make these repairs in the next week or two. Rani has a flight out of Auckland in a month. We will fill up the diesel tanks and plan to motor as needed.

Lessons learned - one should inspect the difficult to access parts of the rig before any larger trip. This could have happened a week later on passage to New Zealand in big seas and with far worse results. We should probably have replaced at least the forestay earlier. The rig was last re-done late in 2001 and despite sitting in a boatyard in Mexico for 5 of those years is now 12 years old. Finally, the furler foil puts a side load on the top of the forestay. There is a toggle at the mast, but this only handles fore and aft motion. A ball toggle would be much better here as it would allow the stay to bend in line with the furler foil on each tack. It is this repeated side stress that probably resulted in the failure. I have talked to others who have had stay failures and it seems that this kind of forestay failure with roller furlers is not uncommon.


Ann Adams said...

From Charisma: FWIW, I saw a forestay repair that used cable clamps to form an eye on the top of the broken wire and chain to adjust the length and terminate to the masthead. Crude, but if you can't get other materials it works.
What a bummer. Good luck. Hope we see you down here soon!

Anonymous said...

Hi Chris, Bad luck but well handled, good for you!
For what it's worth, Ka'sala has 9/32 Norsman fittings all round fitted to 7mm wire. My understanding is that this is acceptable and it may save you some hastle in sourcing bits. There is a slight difference (0.12mm) but the compression inherent in the Norseman fitting handles it.I replaced my Furlex headstay furler two years ago with a Scheafer 2100 and installed a toggle at the mast head. Side loading on a swage is not good, as you found out.
Whether mechanical fittings such as the Norsman or Stay Lock are better than swages is one of those on-going debates which keep the bar flies at the Yacht club entertained. IMHO either will do if it is properly made - I know I can do a Norsman fitting but I can't always be so sure about a swage done by a strange rigger in a foreign port.
Take it easy.