The yacht SAILABOUT dismasted and lost.

I might add that if you do somehow manage to snap the freestanding mast off, the only things left holding it to the boat are, at most, a halyard or two and possibly a couple of sheets. These are easy to release even under load. When the stayed rig fails, the remaining strong shrouds and stays keep the mast, now a dangerously sharp and heavy projectile, in close proximity to the hull. If the mast is going to go down, I'd sooner it go down and stay behind, than go down and follow the yacht until I can dig out the bolt cutters.

 

I can kind of agree with that logic. The average sailboat, on the other hand, will be around for a long time and all of the problems associated with fully stayed rigs---- crevice corrosion, expense, time-consuming inspection, mast breakage leading to other escalating problems, will also be around.
Dismasting is bad enough without the mast attacking the boat. Anything that could be done to limit such catastrophes by designed-in features should be considered.
Unstayed rigs are catching on, in any case. The do have big diameter masts, however, which bothers some people. The influence of racing, like with cars and motorcycles, has led the average sailer to look at speed as the primary goal, leaving reliability, low cost, safety, and ease of ownership by the wayside. Reasons I have a gaffer, which has no turnbuckles, no mast tangs, and no manufactured parts except a few small pieces of bronze. If it breaks, I make a new part myself.
Nowadays, it seems the only thing left you can make yourself and then travel thousands of miles is a sailboat. The unstayed rig is a step in the right direction, that's for sure.

A.

 

Some nice nameless person gave me negative feedback for my post above and called me a "Pratt" if you have a ***** with something that's been posted for christsake it's a forum ....air your grievance and let people have an opportunity to either correct their post or argue their case........OK

 

The old (well, fairly recent I guess) neg-feedback thing rears its head again.... I got a red mark on mine too last week, with the comment "totally wrong information"... in response to a polite request for more details about a newbie's electrical troubles. Might there be an anonymous troll who's simply out to stir up dissent? I vote we simply ignore said anonymous troll.
As for the chainplates and rigging... I'm afraid Mike's post on the previous page is dead right. Sound engineering has gone the way of the dodo in many fields and I'm awfully scared to think that boatbuilding might be heading down that path. We, the boaters, need to demand and expect better.

 

Mike,

I thought your post was excellent and very informative. My guess is that the person providing the feedback couldn't understand it or is just one of those shallow people who get off on being irritating. There's no shortage of either personality disorder anywhere, so I guess we just have to live with them. I agree it's irritating, though. Consider the source and just ignore it. We've got boats to design and play with.

Bill

 

The yacht Sailabout dismasted ......

Interestingly the RAF experimented with simple sharpened steel rods as an anti-submarine weapon in the early days of WWII.

 

Neg rep from unidentified people, only qualify themselves for the worst. Usually big egos, little brains and cowardice. Don't worry and go ahead. All of us know who are the interesting and collaborative members to these forums and who are not.
Cheers.

 

Something else on 'Sailabout' case:
http://www.mmsn.org/events/sailabout.html

 

"Damage to the bow when the forestay was lost"

But the mast did not fall. I wonder if the pulpit and/or bobstay carried away? Anyway, holes in the boat are what sinks them. Seems the mast was still up and she was afloat when abandoned.

 

Mike,

I agree with you completely. No question it has got to be most frustrating when nameless folk can reduce a rep simply by checking "don't approve". Personally I'd like to see that whole system changed. As it is now it does not appear to serve the purpose intended,. A bored teenager, for example, can reduce the forum "reputation" of an experienced sailor or designer, with no basis whatsoever, merely by clicking a button, and not be held accountable. Something is wrong here. The people who do this are wrong, but having a system which facilitates their actions is equally wrong.

Moving on to the more important issues ... Your own post, in my humble opinion, was well thought out, and the sample photo you gave illustrated your point perfectly. That particular chainplate was obviously a victim of "cost engineering", and failed in a manner I would have predicted, for several reasons:

1. The metal is too thin, allowing "working" movement leading to fatigue failure.

2. It is welded rather than cast or forged as a single piece (saves weight and cost, but introduces and enhances stress).

3. The brown spots are evidence that it was not pickled and passivated properly. Failure to remove microscopic iron particles on the surface of stainless steel following welding will weaken its resistance to corrosion. The importance of this process, too often omitted to reduce costs, has been highlighted by recent research. It has been common knowledge for a long time that even minor contact with mild steel (wire brushes, storage racks, welding tables, etc.) deposits iron particles on stainless steel surfaces. More recent study, however, has revealed that minute amounts of iron are evaporated during welding of even low carbon stainless steels, and this evaporated iron condenses on the stainless steel surface near the weld. http://www.future-fab.com/document.asp?d_id=3726

4. For cruisers and liveabords who spend most of their time in warmer climates, a new factor has been discovered which multiplies the effects of these poor design and fabrication practices. Research prompted by increasing evidence of corrosion failures of even low carbon austenitic stainless steel pipe and fittings in SWRO installations (SWRO = seawater reverse osmosis) has revealed the previously unrecognized role of even moderate increases in temperature in accelerating chloride corrosion. http://www.swcc.gov.sa/files\assets...EHAVIOR OF AISI 316L SSIN ARABIAN GULF SE.pdf

In other words, fabricated fittings that may resist seawater corrosion very well in water temperatures of 25 deg C (77 deg F) and below will corrode much more rapidly in water temperatures of 30 deg C and above. The maximum acceleration of corrosion occurs between 25 and 35 deg C. The practical effect is that the most popular cruising waters are much more corrosive to stainless steel fittings than temperate or colder waters. In the reverse osmosis desalination industry the problem has been addressed with the introduction of a variety of more costly alloys. Marine fitting suppliers, however, seem not to have changed from 316L and similar low carbon austenitic stainless steels.

The inevitable result of any one condition described above is premature failure. Combining the four in one fitting is a recipe for disaster.

The more recent report from MMSN posted by Guillermo is significantly different from the initial report in that there is no mention of the mast failing. If this report is accurate, the damage was in the bow. The photos of Sailabout show 2 forestays, which may explain the fact that there was no dismasting. What little evidence there is seems to support your theory that this accident was precipitated by the failure of a fitting.