Hi All Today I was advised, I hope incorrectly, of the very sad news of a very recent rebreather fatality whereby a solo diver using a DPV in a cave knocked his head causing Loss of Consciousness, subsequently resulting in death by drowning. First of all my apologies if I am referring here to a family member or friend in such impersonal terms, I don't mean to but the only information I have is what I have recited above, which may well be inaccurate. If it is true, it is again another very sad loss and so without wishing to appear insensitive, whilst avoiding the subjects of solo diving and the wearing of helmets with a DPV in an overhead environment, I thought I would start a dialogue on a subject I have been an advocate of since my very first days of rebreather diving some 22 years ago - that of the use of a mouthpiece retaining head-strap. For those who may not have read a paper I wrote last year titled A Survival Guide To Rebreather Diving (available from the downloads section of Haynes Marine Ltd web-site) I have pasted the paragraph on this subject below and would be interested to hear what the current consensus is amongst the membership. Rgds Paul Mouthpiece Head-Strap Looking at rebreather incident reports and in particular the excellent rebreather fatality analysis undertaken by Diver’s Alert Network (DAN), although the triggering events and the problem that disables the diver are perhaps most important in understanding accidents and how to prevent them, the fact remains that in most cases the eventual cause of death was drowning. In at least some accidents a disabling problem (such as an oxygen toxic seizure) might not have led to drowning if the diver had been wearing a mouthpiece head strap. Unless used with a full face mask, every military rebreather I can recall, both of classic and contemporary design, uses a mouthpiece retaining head-strap. The reason for this is simple, in the event of Loss Of Consciousness (LOC) there is a reduced likelihood of dropping the mouthpiece and of subsequently drowning. In other words a simple strap, similar to a mask-strap, secured to the mouthpiece, when worn correctly increases the chances of surviving the most common cause of rebreather deaths. Yet it appears that its use is resisted by both sport rebreather manufacturers and the majority of non-military rebreather divers I have discussed the matter with. Having a military rebreather diving background, I have been conditioned to use a rebreather mouthpiece retaining head-strap from day one of my rebreather diving career. I continue to do so and I encourage my students and diving buddies to do so. Besides its obvious potential benefit should you fall unconscious, a mouthpiece retaining head-strap relieves the physical effort and resulting jaw fatigue of having to hold the mouthpiece for extended periods. In contrast to common misconception, when removed, pulled down and placed on the upper chest, the use of a mouthpiece retaining head-strap does not prevent or hinder the quick removal of the mouthpiece should you need to switch to an open circuit bailout demand valve. Thirty years ago in the UK, there was considerable resistance from the motor industry and the motoring public to a proposed new law to make the use of car seat belts mandatory. Thankfully, despite this resistance the law came into force and driving accident fatalities immediately dropped by a significant amount. Today very few of us would consider setting off in a vehicle as either a driver or passenger without wearing a seatbelt, the use of which has become part of driving safety culture. In my opinion it is likely that the rebreather fatality list would not be so long had the use of a mouthpiece retaining strap been common practice. Again I say be a thinking rebreather diver, use a mouthpiece retaining strap and the probability of encountering the hazard of drowning, the single largest cause of rebreather fatalities, will be reduced.
Hi Paul, I think you have opened a can of worms here regarding personal liberties and personal responsibility. Making an actual law to force seatbelts is a violation of personal liberties. No one should be forced to use protective equipment if they don't want to. At the same time, they should be held personally responsible for the consequences of not using said safety equipment, and not try to place the blame on everyone but themselves. Consider this, wearing a helmet while driving a car is safer than not wearing one. Yet I bet you: 1) Don't drive with a helmet 2) Don't want laws forcing you to wear a helmet when driving. 3) Probably will choose to wear a helmet when doing riskier activities like racing a car on a racetrack. People have the ability to weigh up risks and decide what level of risk they are personally comfortable with. Taking a paternalistic attitude to law making leads to nanny states like the one I'm living in now (where rebreather diving on charter boats is so regulated as to be functionally outlawed). Laws that I would support, however, are those that would give legal backing to personal responsibility when carrying out activities that are dangerous only to oneself. Thus if you do something at your own risk and things go wrong, the courts put the blame squarely on you and nobody else. So informing people to use a FFM or gag strap is all well and good as long as it stays as informing and does not develop into enforcing. -Marek
The same as is on the Draeger Ray. The first place I saw it was on the LAR-V. All rEvo's come with the Ray one installed, Paul R. is smart abnout that. Have a pic Paul? I'm out in the field and cannot photograph one. Dave .
Nobody is enforcing anything, and it's hardly likely that posts here will cause a uproar in Parliment causing hasty legislation to be passed... there's plenty of room for all opinions. Paul's made no suggestion of anything mandatory. Let's not argue about politics please? Gents? None of this: :argue: OK? Back to our regularly scheduled programme (note non-colonial spelling for Paul and our friends in the Antipodes) Paul is dead on... the safety notwithstanding, the comfort of a gag strap makes rebreather diving a more enjoyable experience. And I second Paul's statement about the strap not interfering with bailout: Just pull the DSV straight down and bail out... it'll be there under your chin when you want it again. Hmmm... not like the guy who's groping for his over his head. And as another good part of the equation, a DSV pulled down like that, even unclosed, will not vent the loop out immediately with resulting huge buoyancy loss and immediate total flood on those rigs sensitive to such things (Mark-15, KISS, rEvo, etc). Just another tool in the box, actual mileage may vary. Dave .
Perfect, thank you Peter! Note the very soft foam surrounding the mouthpiece. This seals against the outside of the divers lips. When correctly adjusted you can do a full mouth-open yawn and still breathe. No need to even bite down at all on the bite piece. Totally relaxes your jaw. If you have any TMJ it's especially nice to find your molars are still lined up after a long dive. Dave .
I did have trouble when I was using the gag strap with a DSV. I was pushing it up when bailing to OC. Now I am running a BOV and have yet to give it a go. I willl put it on tonight and see.... I will say that I loved the gag strap for longer dives. Quite relaxing. If you want to look around, just look. No need to hold the mouthpiece in place. Peter
I don't dive the stock Draeger DSV on my rEvo anymore, as I use a Shrimp BOV now, so don't know if pulling it straight down is possible or not so won't argue that point. I do know that I can't pull the Shrimp straight down without it digging into the bottom of my neck/chin. Anyways, even with the stock DSV it's just a simple thing to remove the strap and bail. Did it countless times during MOD1. I do prefer bailing on the Shrimp though :thumbsup: Franco
Great post... Thanks for sharing. I took my gag strap off when I installed my shrimp but now I'm thinking otherwise. Anyone know if it fits on the shrimp without any issues or modification?
Thanks for the pics I used to use a simple Velcro strap but it wasn't great ... this looks much much better
I use a gag strap on my JJ and my Inspo with no problems. just pull down to use offboard bail very comfortable n better for scoots Sent from my iPhone using Tapatalk
The only thing I find slightly annoying with the gag strap is when I'm doing some drills, remove the strap & when I put it back on, grabbing those little tabs with heavy gloves on to cinch it up. I usually initially grab the other small tabs and try to give those a yank and when there's no give, I realize I have the wrong tabs. Other than that, I don't even realize it's there. +1 for no mods needed for it to fit the Shrimp. Franco
I have never used a gag strap before. Wondering how it seals if you go unconsious? Your mouth/jaw/lips relaxes how does it prevent water from entering?
I don't know about all of them, but the stock rEvo one has some extra bit of sealing surface around the actual mouthpiece. As the strap holds the mouthpiece in place it also holds the seal to your lips. It does not form a perfect seal, but it helps. Personally, I could not stand it and removed it immediately.
Box it up and send it here then, I need a second for Jitka's Meg. PM me and let's wrangle a deal. Dave
How easy is it to fit the Drager / rEvo one to a BOV such at the Shrimp? Dav Sent from my iPad using Tapatalk HD
