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Old 25-07-2016, 12:29   #16
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Re: Forestay failure on mast crane

Interestingly enough the retaining pins were installed correctly and remain perfectly intact now that they are back on deck As to the integrity of that section of the mast as you have suggested, may well be the issue.

It is going to be so very interesting to reveal the broken area to all of you when the mast is down and I am able to post the photographs - and your comments will be intriguing.

I will move with this as quickly as I can.
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Old 25-07-2016, 12:35   #17
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Re: Forestay failure on mast crane

This is an old Proctor mast so the Selden idea is good - I'll do that thank you Barnakiel
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Old 25-07-2016, 14:43   #18
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Re: Forestay failure on mast crane

I used to have a boat where the masthead was a cast shoe that sat in and ontop of the tube. It had paths in it for stainless straps to run fore + aft and port + starboard, the ends of those straps were attached to the shrouds + stays. This masthead assembly had no welding whatsoever.

Come to think of it, thats exactly how my spruce mast worked too, minus the shoe.

Just another possibility for masthead hardware which may or may not be of any use to you whatsoever.
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Old 25-07-2016, 16:55   #19
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Re: Forestay failure on mast crane

With aluminium welding, the weld is always the weakest link . On the other hand ,with steel the weld is always the strongest link.
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Old 26-07-2016, 05:12   #20
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Re: Forestay failure on mast crane



http://snowpetrelsailing.blogspot.co...l-variety.html

Interesting to see if its a similar failure mode. Alloy in tensile is much more prone to problems like this than a mast in compression.

Weilding in new material might be possible, ideally make it thicker! Or a bolt on plate could be used of some sort? Another possibility would be to put a stemball tyoe fitting on the top or a solent stay type fractional forestay fitting near the top, losing some forestay length.

Id check the backstay plates as well, and maybe reinforce them as well.

Interester to see more pics.
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Old 26-07-2016, 06:10   #21
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Re: Forestay failure on mast crane

Snowpetrel, good points. Hope it's okay if I embelish a bit.


Quote:
Originally Posted by Snowpetrel View Post


Snowpetrel Sailing: Fatigue... of the metal variety

Interesting to see if its a similar failure mode. Alloy in tensile is much more prone to problems like this than a mast in compression.

Weilding in new material might be possible, ideally make it thicker! Or a bolt on plate could be used of some sort? Another possibility would be to put a stemball tyoe fitting on the top or a solent stay type fractional forestay fitting near the top, losing some forestay length.

I think where you're talking about a Solent Stay attachment fitting, your referring to what riggers call a "nose". It's a piece that has a cross section & shape which matches that of the mast, but only covers about 40% of the masts circumference. Though in addition to the bit which mates up with the mast, there's an integral stout tab/beak looking piece on it's front side, which sticks out like a nose. To which the stay is connected.

Also, to put it politely, socketed mast fittings for the most part, are known for frequent failures, & also their short service life. As many often fail with little to no warning, even when having led a gentle life. Something which racers have learned the hard way, going back a couple of decades. As T-balls & the like get used on go fast boats to save weight aloft, vs. conventional wire terminals.

The Cates (Ann & Jim) both were very lucky, & very sharp recently, about catching a T-ball which had cracked in a rediculously short time between inspections. And had they not caught it, they'd be mast shopping right now. It happened all of 2 weeks ago. Here - Norseman fittings sources?

Id check the backstay plates as well, and maybe reinforce them as well.
Yep, I would agree on this!

Interester to see more pics.
I too was thinking that if it was actually a piece of the mast which the OP had fail, then it's time to change things up there. Meaning replace them. And not just the one section which gave way, but everything. As odds are, all of it was made from the same batch of metal, & everything has seen the same service.
Plus, were it me, I'd pull every tang, bolt & fitting, & break out the dye penetrant & a magnifier.

The catch with the masthead itself, of course, as has been stated, is the welding issue. So to me, what makes sense would be to pull the old cap off, & put on a new one. That way the masthead is again all one piece, & likely it's been annealed after fabrication. So when it's installed, the welding which is needed won't (or shouldn't) be in an area which is being pulled on directly (in tension). But instead, is mostly under a bit of compression, & perhaps even then, not directly.

So it wouldn't hurt to think about whether or not it would be nice to incorporate any other features into the new masthead, sheave box, & cranes setup. Ditto on adding any new halyards or stays. Like a Solent Stay & halyard, an extra sheave or bail on the mainsail side, for a Topping Lift which can double as a 2nd Main halyard, etc.

Edit: I forgot to mention it, but the type of "nose" fitting which I mentioned gets affixed to the mast wall via numerous small machine screws. And sometimes they're glued in place, in addition to the fasteners.
Plus there are a few other methods of attaching stays that don't go to the masthead.


PS: I bet blowing out that fitting in the pic was "fun" Occurences like that which can cause gravity storms, bite!
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Old 26-07-2016, 07:27   #22
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Re: Forestay failure on mast crane

I had to read this post, but must admit it brought back a bad memory. Last November our forestay failed in 35 kt. winds and 90 miles offshore....of course it was midnight on Halloween - but who is superstitious. We had to cut the rig free and lost the sails etc. Fortunately, other than the rig and enclosure, the rest of the boat was undamaged and more amazingly, nobody hurt (thanks to our arch). Since our rig is now at the bottom of the Gulf, I will never know exactly what happened, but from the way it came down (fell backwards) and the fact that we had to cut everything at deck level, it had to be the forestay, or a fitting, or attachment point at the masthead. All of this happened despite a visual inspection by a trusted rigger shortly before the trip. We replaced everything using a replacement US Spars mast. I did note that the new masthead was a different design and appeared more substantial than the old one, which makes me suspicious and interested in this type of failure. The new rig now has a removable inner forestay which is attached at all time offshore.
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Old 26-07-2016, 10:05   #23
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Re: Forestay failure on mast crane

These are the photos of the forestay and as revealed the fittings at the attachment point are still intact.
Attached Images
      
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Old 26-07-2016, 10:45   #24
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Re: Forestay failure on mast crane

I expected to see a piece of the masthead still attached, if a weld failed.

But I don't. So maybe it did pull right through the holes in the plates, much like Snowpetrel's chainplate pics. Wow.

Love to know the following, when you get a look, if you get the chance:

- The thickness of the masthead plates that the headstay attaches to

- The diameter of the holes for the headstay pin

- The distance of the holes from the edge of the plate (smallest, worst case). Well, actually, I suppose that's probably obliterated and impossible to tell now. And they look pretty well situated anyways in your first pics.
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Old 26-07-2016, 11:36   #25
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Re: Forestay failure on mast crane

That's a unique one. I wonder what else we'll come to know, as this seems a bit out of the ordinary, at least for moi.

Were it me, I'd leave all of the incorporated pieces together, & just as you recovered them. You never know if you might need to present them to someone for inspection or analysis. Be it a rigger, lab, or the insurance folks.

Saddens me to see them, "live", & to know that your boat & rig are out of the game pending being mended.
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Old 26-07-2016, 13:57   #26
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Re: Forestay failure on mast crane

Quote:
Originally Posted by Frontiersman View Post
These are the photos of the forestay and as revealed the fittings at the attachment point are still intact.
The pictures seem to show an intact pin and flat washers with little or no damage. So my guess is that dissimilar metal corrosion between the stainless steel hollow pin and the masthead aluminum weakened the aluminum. The pictures in the original posting seem to show the aluminum is the thinnest right where the pin applies its load to the holes. Also, it appears the toggle can apply a side load to the pin when bashing upwind. Not a great design IMO.
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Old 26-07-2016, 14:20   #27
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Re: Forestay failure on mast crane

Frontiersman,

Something that might help would be getting in touch with a Moody owners group. Even if none of them have had this kind of failure, i am sure the others would be interested in yours, and if it is a well known flaw, there may also be a well known fix.

Good luck with it, it looks to me like an annoying job.

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Old 27-07-2016, 02:19   #28
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Re: Forestay failure on mast crane

I really struggled with the posting and inclusion of photographs last night but I must succeed in order to do this subject justice - so this then is the result of going onboard yesterday to photograph the hardware that was up on the top attachment point on the masthead when it failed.
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Old 27-07-2016, 03:00   #29
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Re: Forestay failure on mast crane

I am overwhelmed by the generosity of all your replies, your time and care you have all given so freely to this matter, I am most greatful to you.

What remains then, is to photograph the offending bits when the mast comes down and then to reveal the repair - or however the mast is finally restored -and then try to salvage something of this summer's sailing, such as it is.
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