Forums, Mast, Rigging and Sails, Backstay attachment

eldredh at 05/10/2012 17:12:48
We recently had a potentially serious, but in fact inconsequential, failure on Drumbeat when the backstay broke away from whatever it attaches to in the stern of the boat (somewhere in the back locker). Without a detailed examination it appears that 2 or 3 bolts have sheared/broken or come undone. The bolts seem to have attached a piece of metal (shaped like an inverted tuning fork) which is attached to the backstay to something in the boat. Does anybody know exactly how this arrangement works? Should we all be checking these bolts on a regular basis? Perhaps they had come loose and ultimately failed.

George Isted at 08/10/2012 10:03:24
There is a knee that is bonded between the transom and the aft deck, the lower end of the backstay (as identified as an upturned tuning fork) is bolted to this knee. I would imagine that these nuts/bolt could work loose over a period of time. Like all rig fixings I imagine it is worth checking these from time to time, you can see this knee by sticking your head in the stern locker.

Richard Ritchie at 08/10/2012 10:30:25
This is a single point of failure, but not difficult to check. I was pleased I did: peace of mind.
When replacing shroud eyebolts I also replaced these as a matter of safety after 30 years.
As George describes, two stainless bars pin either side of the backstay, pass through the deck and are bolted either side of a glassed in knee between the transom and aft deck. This has a wood core.
My concern was with the bolts, which looked small and were not lock-nutted. And I wanted to check the holes in the knee for wear, since the backstay takes a large stress, and can wobble around when left slackened.
I used new bars (may not be necessary) and larger diameter bolts, long enough for lock-nuts, through new holes (filled the old ones).
It was not a long job but some contortion needed

eldredh at 09/10/2012 15:23:42
Thank you both very much for your input. I’ll get to work. Sounds as though these bolts should be on a regular check list.

moongirl at 04/11/2012 19:49:25
Hi Eldredh
Did you sort out your back stay fixing? We heard the call to the Coastguards as we punched our way on Muscadet back towards Gosport (we diverted into Cowes as it was not seaman like to carry on given the sea state etc)
I would be very surprised if the ‘knee’ was wood cored given that those that support the cap shrouds are solid laminate. given your experience I will check ours when the boat comes out of the water.
Is it snowing in the Front Range?