Snap shackles or Carabiners

[BladesRobinson]

Thanks for reading this far down the post... And thanks for the "thanks."

I realize that working under vessels constitutes an overhead environment but again, we need to remember, "never say never."

My opinion is this constitutes the need for a team decision with everyone being well informed of the risks and benefits. Some are going to be die hard fans, others are going to be die hard opponents. As a team though, ALL must support the majority and make a decision and stick to it.

In a working seaport and under vessels, I may be concerned by the search line being pulled into an open sea chest, wrapped around a turning prop or fouled on a moving vessel. I am not certain I would stick with a hard fast rule of "never say never" when previously I mentioned that we would "never" use a quick release snap shackle in an overhead environment. I this case I may choose the snap shackle or I may choose the locking carabiner.

I would like to ask my teammates what their concerns are for both pieces of gear and make a sound decision based on their input. With an open mind I see the benefits to both! And I see the potential risks of both!

(Good luck Keith and I hope you ankle gets better!)

 

[muddysquirrel]

Thanks for the comprehensive reply Blades, I really appreciate the combination of real-world experience and statistics. This thread (like many on here) has given me a lot more to think about something I thought I had thought about.

 

[BladesRobinson]

Muddy, each year I am fortunate to sit among a group of "egg heads" and give these issues deep thought. We debate the pros and cons of these issues in an effort to have the best/safest training programs possible and offer direction to fellow public safety divers.

We look at accident reports to guide us in the "what if" scenarios and in doing so, we pay tribute to those who have paid the ultimate sacrifice. All of this is in hope that we can prevent the tragic death of a fellow public safety diver. I will apologize in advance if some feel that is self serving but our goal is to help ALL public safety divers. I am proud to say that I think we have been very successful over the years and I vow though that I will never quit learning. I appreciate the smart people on this forum too for sharing their opinions.

If anyone is interested in sharing this opportunity in "real time" I would encourage them to attend the International Public Safety Diver Conference sponsored by the IADRS. The next conference is planed for September 21-24, 2010 in Charlotte, NC. Details can be found online at IADRS.org.

International Association of Dive Rescue Specialists - IADRS

Regards,

Blades Robinson

 

[ChainSaw0069]

Our team switched from the line being fixed to us to using the snap shackles. I like the idea of being able to break free of the line in an emergency.
Im hoping to send a couple of my team to the IADRS Conference this year.

 

[bridgediver]

Hi Blades

I appreciate your passion for the snap shackle and I further applaud your efforts for trying to improve things. We've debated this before and I have given it much thought but I still don't see the locking carabiner as the smoking gun in all these accidents. Like any PIA, each incident will have a whole multitude of factors that usually point to training, safety and procedures well before equipment is a factor.
The biggest question I'd have is do you approve of the use of a snap shackle for ice diving? If not, why would the safety procedures used in ice diving be inadequate for any other PSD dive? Why would we not dive a "system" that works in both environments with no more risk than the other?

I will also mention that snap shackles have been in use for many years in the swiftwater rescue community

A difference between us and the swiftwater guys is that we cannot see our guys if and when they disconnect - we might loose them

The snap shackle was added to the Dive Rescue International curriculum after studying line of duty deaths and the realization that 13% of the Public Safety Diving line-of-duty deaths were attributed the diver being held underwater until he drowned. There were multiple cases where these divers were secured to their "safety lines" by way of carabiners. We know that a diver cannot release out of a carabiner when it is under load and the quick release snap shackle offers a viable option.

Good procedures and practiced contingencies can prevent this as well which will make releasing the connection point irrelavent. There are other options

CCTX50 references a scenario where a diver might pull "the shackle open without the diver knowing until it is too late."

Consider what might happen in 99.99999% of the cases if this very unlikely scenario played out... The diver would come off the safety line and ascend to the surface. That is not a big deal.

Most of the time, I agree. Surfacing is not a big deal but I know of at least 1 incident where a diver had a secondary entanglement (preventing surfacing) during an ascent after disassociating with his line (fortunately he was able to disentangle himself before running out of air). Not only is the diver trapped but now we cannot find him because he disconnected.
If we check with DAN, most dive accidents occur upon ascent. We need to know 100% where our diver is at all times (especially if he's in trouble!). I don't think assuming he will just surface by himself is good enough in PSD
We all know that entanglements happen a lot and sometimes in more than one spot - not always just the line

Dying is a big deal and we know that there are multiple cases where the carabiner was a component in a system that held a diver underwater until he died. The quick release snap shackle offers a better option than the "dive knife & carbiner" option.

Where was the back-up diver? redundant air source? -- I just don't think its as simple as that, sorry
minor point but for this debate but - I wouldn't use a knife if it came to that either. Shears are much safer and faster

Additionally, remember that the diver is holding onto the search line and the quick release snap shackle is attached to the center pivot point on the chest harness.

Many teams use both hands to search so aren't holding onto the line (you can search twice as fast with 2 hands)

IF the snap shackle were to release by accident, in most cases the diver is still griping the search line. For many years this was the only way the diver was attached to a search line and I do not recall one fatality that was caused by a diver losing his grip on the line.

Lastly, consider the number of sailboats that use a quick release snap shackle as an integral component of their sail systems. Tens of thousands, if not hundreds of thousands of these quick release snap shackles are in use and the incidents of failure are practically non-existent. If a failure is reported, it is typically corrosion and the failure of the shackle to open easily. Essentially, IF they fail, they fail in the "safe" (closed) position.

I know of one person from New York who states that she has witnessed hundreds of failures and I find it ironic that thousands of people I know, including myself have NEVER seen a failure.

I would encourage you to try the system yourself and make your own determination.

Respectfully,

Blades Robinson[/QUOTE]

Not going to debate statistics with you because I don't really have them but evaluating statistics will rarely produce the same outcome every time. We all intrepret things differently.

 

[bridgediver]

It surprises me that many of the discussions on the online forums reference worst case scenarios that require a back up to the back up, and a back up to the second back up, and another back up to the third back up ... with one thing backing up another and and another thing backing up another ... you get the point.

Why? The old boy scout moto: be prepared.
The searching and diving is the easy part. Running through sfaety drills and contingency stuff - that is the real meat and potatoes of PSD IMO. It creates huge amounts of confidence in the team in that they know they're ready for any problem

There are divers who carry redundant pony bottles with diverter valves to the full face mask in case they forget to monitor their air supply, their tender fails to monitor their air supply and the back up diver, safety officer, team leader and others fail to monitor the diver's air supply. Then the diver carries a spare mask in case he has to doff the full face mask, and he has a spare second stage if the primary second fails and another second stage on the redundant in case the diverter valve or full face mask fails. And all of this is to cover an unlikely event.

Unlikely, yes. But planned, practiced and prepared for nonetheless.
BTW - the redundant air supply isn't used as a crutch for failure to montior air supply...

Based on 50 years of line-of-duty death research, the facts prove that a diver is far more likely to drown because his search line/carabiner holds him underwater..

How about because his team was unable or didn't know how to free him safely?

 

[muddiver]

The commercial diving community (in the U.S. anyway) has been using spinnaker shackles for many years on the divers umbilicle. The reasoning is that a commercial diving (and Navy diving) umbilicle is very difficult to sever. If it becomes fouled the diver might not be able to cut through the air line, rope, comm line and pnumo hose. Therefore the use of the spinnaker shackles (not to be confused with a snap schackle or bolt snap that can snag) is used to allow the diver to ditch his line to the surface and go on bailout to escape.

In the PSD world it might not be that difficult to slice through your safety line, if that is all it is, a line, or rope. If you are using hardwire comms to the surface than the story might be different and a quick release connection might be in order.

Either way spinnaker shackles have been used safely for many, many years since the transition from the old Navy MK IV heavy diving dress to the modern commercial diving rigs where the diver's umbilicle is tagged to a body harness.

Oh, and carabiners where never designed to be used underwater. The non-locking type will snag and foul on everything, and the locking type can and do often jamb closed from grit or suger sand getting in the screwdown lock. Also the springs are normal spring steel that can and will fail from corrotion that you can not get to because the springs are inside the shackle porting of the carabiner. Stick to high quality stainless steel or bronze graer with stainless steel springs.

 

[Chad P.]

I probably should stay out of this discussion as I have limited experience compared to several of the other people posting, but this will not be the first time that I have not done what I should and certainly not the last time either.

During the past 5 years I have been doing PSD, our team has always used a carabiner set-up. It is something I am comfortable with and has worked well for us. After reading this post, I am definitely interested in looking at the snap shackle as some very good points are offered. As in most things there are pros and cons to both the carabiner and the snap shackle.

Based on some of the comments made, there seems to be an either this way or that way attitude as to which one to use. Personally I do not believe this should be the case. Each situation we encounter as PSD's may be similar but there are almost always variations. What may be the preferred set-up for a dive today may not be optimal for a dive next week due to varying factors (location, water levels, weather, etc.). Training is the key to what we do, and I think we sometimes do ourselves a disservice by eliminating options. I have had instructors tell me you should always use a harness with the rope attached while another instructor said the harness will get you killed and you should only use the hand held safety rope method. I have had training in each method. Now it is my responsibility, and that of my team, to assess the situation before us and then determine what is the best set-up. Not because of what some instructor said, but based on knowledge of the task at hand.

Bridgediver used the example of "why would the safety procedures used in ice diving be inadequate for any other PSD dive?" (Not singling you out Bridgediver, just using this as an example.) The safety procedures might not be inadequate, but they may not be optimal. I'm in south Georgia. We don't get much ice diving this way. Our dive and procedures should be planned based on the conditions we are diving, not what works in some other environment. The same as with the member who posted about overhead environments. The equipment and set-up should be based on what will work best for that dive, and we should always remain flexible to change to a different set-up if it is more benficial. The only absolute should be to rule out that which is unsafe and not worth the associated risk.

 

[Thalassamania]

The commercial diving community (in the U.S. anyway) has been using spinnaker shackles for many years on the divers umbilicle. The reasoning is that a commercial diving (and Navy diving) umbilicle is very difficult to sever. If it becomes fouled the diver might not be able to cut through the air line, rope, comm line and pnumo hose. Therefore the use of the spinnaker shackles (not to be confused with a snap schackle or bolt snap that can snag) is used to allow the diver to ditch his line to the surface and go on bailout to escape.

In the PSD world it might not be that difficult to slice through your safety line, if that is all it is, a line, or rope. If you are using hardwire comms to the surface than the story might be different and a quick release connection might be in order.

Either way spinnaker shackles have been used safely for many, many years since the transition from the old Navy MK IV heavy diving dress to the modern commercial diving rigs where the diver's umbilicle is tagged to a body harness.

Oh, and carabiners where never designed to be used underwater. The non-locking type will snag and foul on everything, and the locking type can and do often jamb closed from grit or suger sand getting in the screwdown lock. Also the springs are normal spring steel that can and will fail from corrotion that you can not get to because the springs are inside the shackle porting of the carabiner. Stick to high quality stainless steel or bronze graer with stainless steel springs.

Like MudDiver I'm used to a wire rope strength member that precludes cutting your way through it with anything but power tools or a torch. Somehow the idea of using anything less for a strength member gives me the willies, perhaps we should start a separate thread on umbilicals?

 

[CCTX50]

Chad, keep on posting! Newbies to the most experienced bring something to the table (forum). That is why I started this thread to get everyones minds thinking and get some feedback as to what everyone out there does. We have used carabiners for years and years and have never had any issues with them. We clean them and replace them as needed. Normally we replace them before they need it due to dive team members loosing them all the time. So we have a healthy supply on hand.

Everyone brings up good points here. Our team also dives with hardhats and SSA. And Muddiver is right that it is VERY hard to cut 4 lines with anything that divers normally carry on them.

A lot of this falls back on training. TRAIN TRAIN TRAIN and then when you are finished... TRAIN somemore. You will do in an actual dive what you have been trained to do. You fall back on training if it has been retained and the key to that is to TRAIN.