InTheDrink
Contributor
Wasn't sure whether to post this but thought might as well in the end.
Some of you may remember Mr Rumsfelds (in)famous quote regarding the known knowns, known unknowns and unkowns unknowns ?
Well I thought I posit some thoughts on this philosophical ditty, but in relation to scuba diving in general and currents in particular. Im hoping that responses from some of the more experienced divers on this board will move some of the unknown unknowns into the known knowns camp, particularly for those of modest diving experience like myself.
I'll start by way of a fairly trivial anecdote about when I was diving in South Ari Atoll in The Maldives last November. I had about 60 dives under my belt at this point, but was diving with my DM buddy. We had rented a boat with a local experienced guide. On the second dive on the first day, in a channel, about 20m down, the current picked up and kept moving up the gears at an alarming rate. I'd been in strong currents before but never anything remotely like this. The three of us were separated by maybe 5 metres each and were holding (clinging?) on to the wall beside us. I found the experience somewhat concerning, but nothing compared to when I started breathing in water not many seconds later. I was still able to breathe some air, but a lot of water was coming in too. I checked my gauge and I still had lots of air. I had no idea what was going on. Just that it wasn't good and to be honest, thought this could be quite serious. Trying to manoeuvre to get my octopus didn't seem attractive as I thought this might make things worse and for fear of getting swept away by the current. Moreover - and I feel this is important - in the heat of the moment, when waters coming in thick and fast, it didnt feel like there were many moments to be playing around with frankly.
I decided I needed to do something so let go of the wall and balooned over to the guide, who could see something was amiss. He ascended us immediately without a safety stop. Back on the boat, I had to ask him what on earth had happened (which in itself annoyed me and is part of the rationale behind this post). He said the pressure of the current had depressed the purge on the second stage which let in the water. This seems to make sense to me, but would be interesting if anyone had any thoughts on whether this could be so or not. And if this was the case, is this the expected behaviour for a second stage or a malfunction?
If so, I must say that I find it strange that in environments with strong currents that they don't tell you certain things:
a) your reg may open up to the water in a strong current
b) if this happens, put your hand over your second stage and/or turn your face away from the current so the second stage isn't getting the full force of the current.
I feel that this kind of incident could become fairly serious fairly quickly, particularly in a current that strong, where maintaining contact with a buddy up-current is nigh on impossible. If there had been a few DSDs or newly trained OWs in tow, and all regs had had the same behaviour, this could have become quite serious indeed.
But my main thrust here is - what other 'unexpected events/situations/gear quirks (malfunctions?)' are there in strong currents that aren't commonly mentioned that maybe should be? Obviously its easier to deal with a situation if you are aware that this situation can happen.
You can think to yourself OK, free flowing reg. Ive read/trained this I can breathe on this and ascend (or share if possible).
Or, mental current, reg letting in water - turn face away from current. Etc.
But trying to work out what to do, never mind executing it, the first time, under stress, is difficult.
Another example - I carried my first reef hook on my trip a couple of weeks back (also to the Maldives and, incidentally, on the Stingray, a sister boat to the Baani Adventure, the day after the accident happened but this is immaterial to this post [though I may have some words to say on this also in another post]).Anyway, I also carried my first knife, after reading about that poor girl on Palau that died, her hook still attached into her BC. I carried the knife having read the following thread on SB (http://www.scubaboard.com/forums/basic-scuba-discussions/25725-lessons-learned-death-palau.html) and even though the currents were much more gentle on this trip, I could see that it makes utter sense to be able to cut oneself free from the reef hook/line attached to your BCD - but only after having read about it here. Otherwise I would have just carried the hook.
So here are my newbie three things that people not experienced in a strong current might want to know:
1. Second stage purges can let in water in a very strong current
2. This will stop if you turn your head away from the current or put your hand over the second stage
3. If using a reef hook, make sure you carry a knife in case the current is too strong to detach yourself from the hook/line (it clips into a d-ring on your BCD)
Now - are there any other lessons about currents that people could learn here, safely, rather than have to learn directly from experience, where their safety may be in jeopardy? What other tips and tricks should one be aware of when going into waters where extremely strong currents are possible?
Or if what Im saying, my lessons learned as it were, are incorrect, Id certainly appreciate feedback on that!
Thanks,
John
Some of you may remember Mr Rumsfelds (in)famous quote regarding the known knowns, known unknowns and unkowns unknowns ?
Well I thought I posit some thoughts on this philosophical ditty, but in relation to scuba diving in general and currents in particular. Im hoping that responses from some of the more experienced divers on this board will move some of the unknown unknowns into the known knowns camp, particularly for those of modest diving experience like myself.
I'll start by way of a fairly trivial anecdote about when I was diving in South Ari Atoll in The Maldives last November. I had about 60 dives under my belt at this point, but was diving with my DM buddy. We had rented a boat with a local experienced guide. On the second dive on the first day, in a channel, about 20m down, the current picked up and kept moving up the gears at an alarming rate. I'd been in strong currents before but never anything remotely like this. The three of us were separated by maybe 5 metres each and were holding (clinging?) on to the wall beside us. I found the experience somewhat concerning, but nothing compared to when I started breathing in water not many seconds later. I was still able to breathe some air, but a lot of water was coming in too. I checked my gauge and I still had lots of air. I had no idea what was going on. Just that it wasn't good and to be honest, thought this could be quite serious. Trying to manoeuvre to get my octopus didn't seem attractive as I thought this might make things worse and for fear of getting swept away by the current. Moreover - and I feel this is important - in the heat of the moment, when waters coming in thick and fast, it didnt feel like there were many moments to be playing around with frankly.
I decided I needed to do something so let go of the wall and balooned over to the guide, who could see something was amiss. He ascended us immediately without a safety stop. Back on the boat, I had to ask him what on earth had happened (which in itself annoyed me and is part of the rationale behind this post). He said the pressure of the current had depressed the purge on the second stage which let in the water. This seems to make sense to me, but would be interesting if anyone had any thoughts on whether this could be so or not. And if this was the case, is this the expected behaviour for a second stage or a malfunction?
If so, I must say that I find it strange that in environments with strong currents that they don't tell you certain things:
a) your reg may open up to the water in a strong current
b) if this happens, put your hand over your second stage and/or turn your face away from the current so the second stage isn't getting the full force of the current.
I feel that this kind of incident could become fairly serious fairly quickly, particularly in a current that strong, where maintaining contact with a buddy up-current is nigh on impossible. If there had been a few DSDs or newly trained OWs in tow, and all regs had had the same behaviour, this could have become quite serious indeed.
But my main thrust here is - what other 'unexpected events/situations/gear quirks (malfunctions?)' are there in strong currents that aren't commonly mentioned that maybe should be? Obviously its easier to deal with a situation if you are aware that this situation can happen.
You can think to yourself OK, free flowing reg. Ive read/trained this I can breathe on this and ascend (or share if possible).
Or, mental current, reg letting in water - turn face away from current. Etc.
But trying to work out what to do, never mind executing it, the first time, under stress, is difficult.
Another example - I carried my first reef hook on my trip a couple of weeks back (also to the Maldives and, incidentally, on the Stingray, a sister boat to the Baani Adventure, the day after the accident happened but this is immaterial to this post [though I may have some words to say on this also in another post]).Anyway, I also carried my first knife, after reading about that poor girl on Palau that died, her hook still attached into her BC. I carried the knife having read the following thread on SB (http://www.scubaboard.com/forums/basic-scuba-discussions/25725-lessons-learned-death-palau.html) and even though the currents were much more gentle on this trip, I could see that it makes utter sense to be able to cut oneself free from the reef hook/line attached to your BCD - but only after having read about it here. Otherwise I would have just carried the hook.
So here are my newbie three things that people not experienced in a strong current might want to know:
1. Second stage purges can let in water in a very strong current
2. This will stop if you turn your head away from the current or put your hand over the second stage
3. If using a reef hook, make sure you carry a knife in case the current is too strong to detach yourself from the hook/line (it clips into a d-ring on your BCD)
Now - are there any other lessons about currents that people could learn here, safely, rather than have to learn directly from experience, where their safety may be in jeopardy? What other tips and tricks should one be aware of when going into waters where extremely strong currents are possible?
Or if what Im saying, my lessons learned as it were, are incorrect, Id certainly appreciate feedback on that!
Thanks,
John
