Hi all

This is a MAIB bulletin regarding tethers that is worth reading

assets.publishing.service.gov.uk/media/5a535cfe40f0b648c72358ff/SB1_2018.pdf

Regards Don

Ramona said..

Donk107 said..
Hi all

This is a MAIB bulletin regarding tethers that is worth reading

assets.publishing.service.gov.uk/media/5a535cfe40f0b648c72358ff/SB1_2018.pdf

Regards Don

Robin Knox Johnston commented on this in one of the Pommie yachting magazines. He reckons that any of the clips would have failed in that situation. None of them can handle side loadings like that that occurred in that accident. The clips only work correctly with direct pulls at full loads.

That doesn't sound right to me. A tether should work 100% of the time regardless of the load direction.
If I knew my tether would have failed under side loading I would have ditched the clip and shackled on to the Jacklines. FFS the tether should be the most reliable and over engineered piece of equipment on the boat. The findings were BS the clips should be able to withstand side loading. Saying they should be setup to avoid any side loading is ridiculous. Make fffing clips stronger!!!!

What Andy said.
Whilst we're on the subject, a bit more idiotic tether trivia...d you know if you're racing in any Sailing Australia sanctioned race (read nearly all), you are only allowed to use a tether that is fitted with all snap hooks.
Stupidly, having a quick release shackle for where the tether attaches to your harness (see pic below) is not allowed.



It's nuts, if you're getting dragged, you have near zero chance of getting a hook undone off your harness, a quick release shackle is so much more logical it's laughable. I have 10 tethers on board to cover for the crew when racing, and I have to buy the snap hook style ends just to be compliant, even though that is potentially endangering the crew.
Sorry, idiot regulation rant over, back to normal programming!

shaggybaxter said..
What Andy said.
Whilst we're on the subject, a bit more idiotic tether trivia...d you know if you're racing in any Sailing Australia sanctioned race (read nearly all), you are only allowed to use a tether that is fitted with all snap hooks.
Stupidly, having a quick release shackle for where the tether attaches to your harness (see pic below) is not allowed.



It's nuts, if you're getting dragged, you have near zero chance of getting a hook undone off your harness, a quick release shackle is so much more logical it's laughable. I have 10 tethers on board to cover for the crew when racing, and I have to buy the snap hook style ends just to be compliant, even though that is potentially endangering the crew.
Sorry, idiot regulation rant over, back to normal programming!

Dunno, SB. YA had been fighting with Standards Australia for years to allow hooks on the inner end of harnesses, prior to the loss of Waikikamukau. Because of SA's attitude, when the Moo Cow started to sink the crew on deck, who were all clipped on, had to get out of their harnesses or reach the clips at the outer end of the line. At least one of them managed to get enough slack to get out of the chest harness itself. I can't recall how the other got unclipped. One crew member never got unclipped and went down with the boat.

The lesson from that (and we got it very early since some of our crew went to see their mate, the sole survivor, in hospital after we were all told to abandon the search as conditions worsened) is that you CAN normally get enough slack for a brief time if the boat is sinking or inverted.

We all know times when snap shackles have come undone. Surely the risk of a snap coming undone, especially if you have been dragged across a deck and lifelines with all the potential snags that means, is greater than the risk of not being able to unclip.

One other point that came out of the '98 Sydney-Hobart inquest was that in some ways, the ultimate strength of a harness is irrelevant. The force required to snap a harness can cause such severe internal injuries that the wearer is not going to survive anyway. I was there when a doctor was giving testimony and I believe he said something to the effect that one of those who died after going overboard and breaking a harness would have had to have been in a fully equipped emergency operating room without 10-15 minutes to have had a chance of surviving after suffering such crushing forces on the abdomen.

Good points Chris It's obvious you know more than me about this. But it seems to me when you look at the pics of the bent hook it seems obvious that it's designed for a straight pull and it doesn't seem that much force was needed to bend the flat stainless laterally.
Shaggy I'm with you on the quick release why can't someone invent something more reliable than a snapshackle that will release under pressure, it can't be that hard

andy59 said..

That doesn't sound right to me. A tether should work 100% of the time regardless of the load direction.
If I knew my tether would have failed under side loading I would have ditched the clip and shackled on to the Jacklines. FFS the tether should be the most reliable and over engineered piece of equipment on the boat. The findings were BS the clips should be able to withstand side loading. Saying they should be setup to avoid any side loading is ridiculous. Make fffing clips stronger!!!!

I tend to believe Robin Knox Johnston's assessment. If you jam any of the top line clips by the lower third and pull upwards they will fail at something like 20% of their rating. These clipper racers are carrying paid "passengers" and all their stuff is top gear. I'm sure their insurance bill is astronomical!
Jam the hook of one of those Wichard clips in a vice and pull sideways with a short bit of rope. I reckon 50 lbs will do it!

It seems the Clipper yachts have wrapped rope around the cleats to prevent further mishaps with clips.

andy59 said..

Ramona said..
It seems the Clipper yachts have wrapped rope around the cleats to prevent further mishaps with clips.

Well that will probably stop that particular instance happening again. Its almost like the tether should come with a warning like "this tether will fail under side loading." it just seems like a negligence case waiting to happen to me.
Free Radical its seems pointless having a short and long tether if you have to be hooked on to the short one all the time.
Why not make hooks that can withstand 500kg side loading?? Would they be too large or heavy??
Edit: a webbing or spectra failsafe loop would do it.

Should be a very easy task to engineer a clip to withstand a 500kg side force, for example a standard ultra light weight alloy non locking rock climbing carabiner can withstand 8Kn side load, which I believe in layman terms is around 800kg.

BlueMoon said..

andy59 said..

Ramona said..
It seems the Clipper yachts have wrapped rope around the cleats to prevent further mishaps with clips.

Well that will probably stop that particular instance happening again. Its almost like the tether should come with a warning like "this tether will fail under side loading." it just seems like a negligence case waiting to happen to me.
Free Radical its seems pointless having a short and long tether if you have to be hooked on to the short one all the time.
Why not make hooks that can withstand 500kg side loading?? Would they be too large or heavy??
Edit: a webbing or spectra failsafe loop would do it.

Should be a very easy task to engineer a clip to withstand a 500kg side force, for example a standard ultra light weight alloy non locking rock climbing carabiner can withstand 8Kn side load, which I believe in layman terms is around 800kg.

It would be the lever action from how the hook was snagged that would be the issue, pretty easy to multiply the load substantially.

Andy, I don't like those uneven tethers, this is what I think is best

I have changed to a central jackline system with "fixed" tethers, as shown in this link:
www.morganscloud.com/category/safety/
So my tethers have a variety of boat-end clips, including some climbing screw-gate karrabiners, and other strong clips. I have conventional double-action clips on harness ends - but I hate them! Any heavy spring clip will do! Much easier for one-handed changes. Sorry no pics.

The rule is: do not go over the side EVER !!