Thalassamania(Offline)

We do a fair amount of what we refer to as blue water diving. This is open ocean work with no bottom. Orientation is critical, as is depth control. Early trials in this technique led to the development of the "blue water rig" which is explained in this publication. One of the things that we found was that we preferred to use spinnaker shackles for many applications that we had previously used bolt snaps for.



Bolt snaps were, in fact, implicated in the death of a diver due to the inability of a bolt snap to be positively released when under load.

Anyway, two questions:

1) What’s with this love of bolt snaps?

2) Is there any reason to not use spinnaker shackles instead?

__________________
“I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it.” Thomas Jefferson

Hybrid(Offline)

One reason (perhaps the most important) is that you can unclip and clip with one hand, without looking at the clip. Which means quick release and return of items without fumbling with them and using two hands, and eyes.

The spinnaker shackles are great for holding huge loads - hench the design - solid pin..etc.. This is which is not needed underwater as items don't weigh much as a rule.

I've used many different clips, before finding that these stainless gate clips are the easiest to use.

Thalassamania(Offline)

Please bear with me, it is not to be argumentative but rather to understand. I can easily clip and unclip a spinnaker shackle with one hand and my eyes closed, much easier in fact with heavy cloves on. Granted they are overkill in terms of load. Would I be looked at askance where I to use them instead?

__________________
“I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it.” Thomas Jefferson

Hybrid(Offline)

They are quite similar, I reckon that a gate clip is quicker to clip up too than spinnaker shackles. I don't have both to do speed tests on. I haven't experienced myself, but many DIR cave divers say other clips are entrapment risks. What is the price of a gate clip vs a spinnaker shackle? If they preform in a what you consider a similar manner. This is nit picking but the ergonomics of a gate clip is better too. You can hold the clip in your hand and clip and unclip without moving your hand position. - The action is the same. With the spinnaker shackles there would be more fiddling. Have you used SS gate clips?

peter_steinhoff(Offline)

It's possible that the shackles you use would be a good choice as well but we have standardized the use of bolt snaps and standardization in itself is very valueable.

We usually clip multiple items to one 2" D-ring and also use boltsnaps of several different sizes. Double enders (double ended bolt snaps) are also common for some uses. The only real load bearing situation is the use of tow behind scooters. They have about 60 pounds of thrust. Most of our other equipment is "kind of" neutral. Over the course of 20 years the bolt snaps have proven themselves as a very good choice for our application.

Regards,
Peter

__________________
Peter Steinhoff
GUE DIR-F, Tech1, Tech2, Cave1, Cave2, Cave3, RB80-1&2, DIR-F/Cave Instructor Candidate.
NAUI Tec Instructor (Trimix, Technical DPV, Technical Wreck Penenetration etc)
WKPP Support Diver, Halcyon Product Development Team, Gavinscooter Representative.
Various IANTD, NSS-CDS, NACD, PADI & NAUI.
----------------------------------------------
http://dir-diver.com
http://peter.steinhoff.se (swedish only)

Thalassamania(Offline)

Quote: (Originally Posted by peter_steinhoff)

It's possible that the shackles you use would be a good choice as well but we have standardized the use of bolt snaps and standardization in itself is very valuable.

Standardization is, indeed, not to be sneered at.

There was a blue water diving accident some years ago, a contributing cause of which was a diver's inability to release a bolt snap that attached the diver to a clump weight that ultimately dragged the diver to the bottom of the Monterey Canyon. At that time the Diving Control Board insisted that all clips that attach a diver to anything be capable of one handed, near-instant release, even when under heavy load. Thus we migrated from a two dollar bolt snap to a ten dollar spinnaker shackle (now more I'm sure). I'm very well drilled with the spinnaker shackles and hate to abandon that skill level, but I can see the logic of having a buddy that understands how to deal with the way in which my gear is put together.

__________________
“I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it.” Thomas Jefferson

BigTuna(Offline)

How does one operate a spinnaker shackle with one hand? On boats, a short lanyard is attached to the pull ring to make it easier to grasp and pull when the shackle is loaded. Do you use a lanyard? Please, I'd like to know!

I've seen spinnaker shackles fail when the pin is pulled too hard, leaving a handful of pieces. Has this been an issue for you?

For security, sailors "mouse" the straight pin to keep it from unscrewing. How do you approach this problem in a diving setting?

Thalassamania(Offline)

Lanyard with a small ball.
Not for diving, but then the stress on the shackles is so small when compared to it's rating.
Not an issue, I should have been more careful with the illustration I grabbed, the ones I use look more like this.

__________________
“I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it.” Thomas Jefferson

LCF(Offline)

I speak as shouldn't, because I don't have anywhere near the experience of the people involved in this discussion, but my bolt snaps are all tied on to whatever they're retaining with cave line. I carry a pair of shears AND a small, sharp knife, both of which are capable of cutting the cave line. I can't see any situation where I'd be tethered or carried to my death as a result of my bolt snaps getting caught on something.

Thalassamania(Offline)

Quote: (Originally Posted by LCF)

I speak as shouldn't, because I don't have anywhere near the experience of the people involved in this discussion,

Then you absolutely should speak up, I’m here to learn as I suspect you are too.

Quote: (Originally Posted by LCF)

but my bolt snaps are all tied on to whatever they're retaining with cave line. I carry a pair of shears AND a small, sharp knife, both of which are capable of cutting the cave line. I can't see any situation where I'd be tethered or carried to my death as a result of my bolt snaps getting caught on something.

Two things to consider:
1) The diver who died in Monterey was a highly experienced diver who couldn’t see any situation where he’d be carried to his death, believe me. But when a bolt snap is under tension, releasing the gate may not break the connection. Are you confident enough in your own skill and practice to reach, with your other hand, obtain a tool and use it before you sink too far? I'm not, and that's what concerns me. Perhaps I'm overly sensitive to this issue, but switching snaps will cost me a whole lot of pool time, and I hate the chlorine.
2) Standardization is important. But it should never override a better way. I don’t know if a change in the type of snap would be a better way or not … I just raise the issue for discussion and will make up my mind in time.

__________________
“I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it.” Thomas Jefferson