Tether Snap Hook Failure - Clipper RTW race

[mike cunningham]

The current issue of Practical Sailor provides some insight into how the Clipper RTW race sailor was detached from the boat and subsequently died.

It's an interesting article. The supposition is the sailor's Spinlock Race Clip which was attached to the jackline was brought up hard under a midship cleat. The dynamics of the way the clip was jammed under the cleat caused the clip to be subjected to a very high side load as the weight of the victim was applied. The clip basket bent open as a result. The tether and MOB detached from the boat and it was over.

Apparently this type of load is common and well understood in the climbing world so climbing equipment is manufactured accordingly.

A long time ago I purchased tethers equipped with Kong Tango snap hooks. I always felt pretty good about these because they are climbing rated gear and are easy to use, although you must always check and maintain them and the rest of the tether hardware.

https://www.kong.it/en/2-products/items/f1-carabiners/p57-tango

Their strength is borne out in the PS testing which looked at side and load found the Kong capable of withstanding more that 1100 pounds while the Race Clip failed at about 300 pounds. One other point about the Kong, while we all know that you must not connect the unused tether of a two legged tether to your harness and, by doing so, defeat the harness quick release, the nose of the Kong is small enough to clip into the fixed crown of the quick release snap shackle (the bit to which the tether is permanently attached). This is really handy for getting the unused leg out of the way.

The other interesting factoid was a second sailor on the bow was also thrown overboard but clambered back aboard partly due to the fact he was clipped in on a three foot tether. The sailor who got separated was on a six foot tether. This reinforces the "shorter is better" mantra.

In any event, the article is worth reading with lots of instructive pictures.

 

[jamottep]

A long time ago I purchased tethers equipped with Kong Tango snap hooks. I always felt pretty good about these because they are climbing rated gear and are easy to use, although you must always check and maintain them and the rest of the tether hardware.

That's what I use too. But this past Tuesday when I was sailing something puzzling happened. I was doing stuff at the bow, can't remember what but nothing that involved contortionism. When I sat down in the cockpit I noticed that my tether was on the foredeck ... It's time to buy a backup.

 

[mike cunningham]

That's what I use too. But this past Tuesday when I was sailing something puzzling happened. I was doing stuff at the bow, can't remember what but nothing that involved contortionism. When I sat down in the cockpit I noticed that my tether was on the foredeck ... It's time to buy a backup.

Interesting. The biggest problem I have had with day to day tether use has been the snap shackle at the harness end. I have found them very easy to accidentally release by snagging or whatever. Although I have never had to test release under load, it is my understanding this can be just the opposite. When you want to release it is very hard to do. Now I am thinking about it, I might just run a personal test to find out how hard it actually is.

I used to work in the satellite building business where loaded release mechanisms were critical (separation rings, solar array release, antenna release, etc.). We had a group of engineers whose job it was to design such mechanisms. Mind you, most of these did the deed using pyrotechnic cutters. I often pondered talking to one of them about designing a mechanism for a marine tether (excluding the pyrotechnics). My supposition is no one has seriously worked on such a mechanism due to liability issues?? I don't know. I am pretty sure most climbers would look at a snap shackle and say "are you kidding me?".

Spinlock wants you to use their tether cutter to release - so you fall off, are now in a washing machine on fast cycle and you are going to find the cutter and cut through the tether Uh huh...

The only other quick release I have seen is similar to what is used for parachutes and one must be careful to repack the release cord properly after testing. Nope, not at sea on the third day of the SHTP.

Another school of thought is if you wind up off the boat you are screwed, so don't wind up off the boat. Not sure how you accomplish this when the boat falls out from under you .