Forestay Failure

[r.fairman]

Whilst removing the genoa from the foil the forestay failed on my 2007 Mac M.Near disaster but managed to control the fall of the mast and only sustained gooseneck damage. All the stainless wires had failed where they enter the top swage of the forestay. This could have happened at sea with serious consequences. The mast has been up since 2007 and not be subjected to any serious stress The wires has not pulled from the swage but parted where they enter the swage. All seem to have parted at the same time as the fractured ends are clean and shiny. Perhaps the swaging machine had pinched the wires? I am now doubtfull about all the swaged terminals on the boat. I will post photos later.

any comments

[Catigale]

I suspect the forestay was too loose, and this was a fatigue failure, not a failure under tension

I dont think a swage tool can compress a multiwire shroud enough to a shear failure mode.

[Russ]

Please post some close up pictures. The mechanical engineering types might have some interesting opinions.



--Russ

[restless]

Eeeek... seems you had your guardian angel close by. We had a similar thing... nearly. De-rigging after our first outing I noticed the top swage was a bit frayed. My blood ran cold when I looked into it further and realised we'd been sailing with 2 strands holding the whole rig up !!!!!!!!!!
My theory is that when the mast comes down, the forestay+furled sail puts a nasty kink at exactly that point. For that reason whenever I step the mast (every time I launch) I unclip the top and stow the foresail assembly along the deck. Bit of a fiddle, but when I think of the mast coming straight into the cockpit I just get on with it!

[Doug91mac26s]

I have a CDI furler, with internal halyard, freeing up the original jib halyard. I use the unused halyard as insurance, attaching it to the bow pulpit where the base of the mast attaches while trailering. If the forestay lets loose that halyard connection will keep the mast from falling.

Also while trailering I make sure the furler is fastened securely to the mast, flat, with no unnecessary stress pulling to the side, I haven't had any trouble so far.

[DaveB]

Ck to see if there is a toggle on both ends of the stay, this is a must for CDI roller furler. The wire will fatuge at the swag point if there is no Toggles and snap the 1x19 strands. Put some dye over the swag fittings to see if hair line cracks appear.
If you have the standard 1/8 wire redo with 5/32 , this wire will also fit the CDI#2.
Ck page 7 to see if this is how your toggles are.
http://www.sailcdi.com/sailpdf/FF2%20manual%207_06.pdf
Dave

Whilst removing the genoa from the foil the forestay failed on my 2007 Mac M.Near disaster but managed to control the fall of the mast and only sustained gooseneck damage. All the stainless wires had failed where they enter the top swage of the forestay. This could have happened at sea with serious consequences. The mast has been up since 2007 and not be subjected to any serious stress The wires has not pulled from the swage but parted where they enter the swage. All seem to have parted at the same time as the fractured ends are clean and shiny. Perhaps the swaging machine had pinched the wires? I am now doubtfull about all the swaged terminals on the boat. I will post photos later.

any comments

[waternwaves]

The mast has been up since 2007 ...........

in the water? on on a trailer?

the top of the forestay failure is probably the most common failure locations. (at least every forestay, backstay wire failure I have had has been up top.)

dont discount corrosion here. between the bird poop, and the infrequent inspection when the mast stays up, it is pretty common.

and if on a mooring ball the pumping can be severe if one or more shrouds or stays is loose

[Terry]

If you have the standard 1/8 wire redo with 5/32 , this wire will also fit the CDI#2.
Ck page 7 to see if this is how your toggles are.
http://www.sailcdi.com/sailpdf/FF2%20manual%207_06.pdf
Dave

Whilst removing the genoa from the foil the forestay failed on my 2007 Mac M.Near disaster but managed to control the fall of the mast and only sustained gooseneck damage. All the stainless wires had failed where they enter the top swage of the forestay. This could have happened at sea with serious consequences. The mast has been up since 2007 and not be subjected to any serious stress The wires has not pulled from the swage but parted where they enter the swage. All seem to have parted at the same time as the fractured ends are clean and shiny. Perhaps the swaging machine had pinched the wires? I am now doubtfull about all the swaged terminals on the boat. I will post photos later.

any comments

If one is going to upgrade the wire to 5/32, then one should also consider upgrading the 1/4 turnbuckle to a 5/16 turnbuckle, the next size up. This is what I did to accommodate my Schaefer CF700 Snapfurler and it really gives me peace of mind to know I have a stronger setup. The larger turnbuckle should also fit the CDI furler.

[Doug91mac26s]

That's exactly what I did. When I installed my new CDI FF2 with a 150 genoa, I had a new 5/32 forestay made with 5/32 hardware, with toggles. But keep it flat and secure bungee'd to the mast while trailered.