I think Cerich could be right with the octo and Miketsp could be right on with the folded exaust caused by entry. I wouldn't be a bit supprised if the LDS finds nothing wrong with either regulator.
Scubapro failure at depth
- Thread starter gotsand
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The odds are against it being anything other than water in the tank.
Having two exhaust valves fold simulaneously and then also have neither one of them unfold itself during the dive is extremely unlikely. An identical failure in both second stages is a very, very low probability occurence anyway, which leads up the chain to a possible first stage problem.
But...any hole, leak or damage to the first stage that would let large amounts of water in would not happen as the same problem would first let large amounts of air out - and flooding would not be an issue until you were out of gas anyway, so that indicates it was clearly not a first stage problem. When first stages fail it is almost always in the form of passing excess gas past a damaged seat or orifice. In exceedingly rare cases where a mainspring may break, a first stage could possibly fail closed and deliver no gas at all. Everything else that is possible just results in fairly minor amounts of gas leaking past a bad o-ring.
That leaves the tank. And a situation where both regs deliver water when you are in a head down position is a classic example of having either an awful lot of water in the tank or, a still impressive amount of water in a tank with a missing dip tube (which normally keeps a small to moderate amount of water from finding it's way into the reg.)
Tear down of the reg in this situation should show signs of flooding and possibly contamination from corrosion products, salt, etc that may have been in the water. The filter would usually show evidence of this on an external examination.
If it happended to me, my first act on surfacing and getting back aboard would be to disconnect the tank, invert it and crack the valve to see what happens. If you find your self holding an impressive imitation of a super soaker, you've found the problem. Finding (or proving) that same problem is much harder after your annonymous rental tank finds it's way back into the rental tank rack.
If water in a rental tank caused the problem, the shop needs to cover the cost of the teardown, drying and annual service of your reg (and I'd do a full annual service as bits of rust, corroded aluminum, salt, etc, do bad things to o-rings and seats and they should be replaced.
Having two exhaust valves fold simulaneously and then also have neither one of them unfold itself during the dive is extremely unlikely. An identical failure in both second stages is a very, very low probability occurence anyway, which leads up the chain to a possible first stage problem.
But...any hole, leak or damage to the first stage that would let large amounts of water in would not happen as the same problem would first let large amounts of air out - and flooding would not be an issue until you were out of gas anyway, so that indicates it was clearly not a first stage problem. When first stages fail it is almost always in the form of passing excess gas past a damaged seat or orifice. In exceedingly rare cases where a mainspring may break, a first stage could possibly fail closed and deliver no gas at all. Everything else that is possible just results in fairly minor amounts of gas leaking past a bad o-ring.
That leaves the tank. And a situation where both regs deliver water when you are in a head down position is a classic example of having either an awful lot of water in the tank or, a still impressive amount of water in a tank with a missing dip tube (which normally keeps a small to moderate amount of water from finding it's way into the reg.)
Tear down of the reg in this situation should show signs of flooding and possibly contamination from corrosion products, salt, etc that may have been in the water. The filter would usually show evidence of this on an external examination.
If it happended to me, my first act on surfacing and getting back aboard would be to disconnect the tank, invert it and crack the valve to see what happens. If you find your self holding an impressive imitation of a super soaker, you've found the problem. Finding (or proving) that same problem is much harder after your annonymous rental tank finds it's way back into the rental tank rack.
If water in a rental tank caused the problem, the shop needs to cover the cost of the teardown, drying and annual service of your reg (and I'd do a full annual service as bits of rust, corroded aluminum, salt, etc, do bad things to o-rings and seats and they should be replaced.
Hank49
Contributor
gotsand:
DA Aquamaster, as usual your post is right on except for this statement he made in a previous post. Unless they didn't tell the truth, which, if they had to pay for any reg cleaning, could be the case.
halocline
Contributor
I'm starting to like the theory that your primary 2nd stage flooded (exhaust valve) and you just didn't purge the alternate adequately, but not as much as I like the water in tank theory. (Maybe the LDS did not really inspect the tanks that were used) Of course, there is the "sabatoge to both 2nds" theory. Anybody on the boat that would have a reason....oh forget it. Just kidding!
Liability avoidance and other conspiracy theories aside, after getting shots of water with both second stages on more than one occasion durign the dive it's possible the tank finally went dry.
I guess the reason that I would question the "water in the tank" causing the problem would be the fact that it was salt water. I agree that a close inspection of the first stage screen should reveal if there was water in the tank. I am curious to see what the LDS finds.
We have some history to keep track with for Mk20, right?
"water in the tank?" maybe less possible, because you don't see the problem until 85 feet, by that time, you've probably done different gestures during the dive (=> different tank orientation). Maybe pressure triggered for something in marginal condition.
My guess is the 1st stage.
I would also think that the 2nd stages are probably alright, because the probability for both of the 2nd stages failing at the same time is relatively low.
"water in the tank?" maybe less possible, because you don't see the problem until 85 feet, by that time, you've probably done different gestures during the dive (=> different tank orientation). Maybe pressure triggered for something in marginal condition.
My guess is the 1st stage.
I would also think that the 2nd stages are probably alright, because the probability for both of the 2nd stages failing at the same time is relatively low.
There is just no way for water to enter the first stage upstream against 120 to 145 psi of pressure to get into the intermediate air passages and eventually into the LP hoses and second stages.
However you are implying cracks in a Mk 20 first stage body, where the yoke retainer screws in, could allow water in. That would mean the water is traveling into the regulator against potentially 3000 psi of air pressure. It's not going to happen - ever.
In reality any first stage failure would mean lots of gas escaping the reg through any crack, hole or failed o-ring. Water is just not going to enter the reg until the tank is bone dry - and then you'd still have to continue going deeper to create a negative pressure gradient across the crack.
It's either water in the tank or a bizarre situation with holes in both second stage diaphgragms and/or torn or folded exhaust valves in BOTH second stages, which is again very unlikely.
However you are implying cracks in a Mk 20 first stage body, where the yoke retainer screws in, could allow water in. That would mean the water is traveling into the regulator against potentially 3000 psi of air pressure. It's not going to happen - ever.
In reality any first stage failure would mean lots of gas escaping the reg through any crack, hole or failed o-ring. Water is just not going to enter the reg until the tank is bone dry - and then you'd still have to continue going deeper to create a negative pressure gradient across the crack.
It's either water in the tank or a bizarre situation with holes in both second stage diaphgragms and/or torn or folded exhaust valves in BOTH second stages, which is again very unlikely.
R
redacted
Guest
DA Aquamaster:
At least one of which worked OK until the diver got to depth and assumed a head down position. Then it takes on water until he raises his head again. :light:
captain
Contributor
DA Aquamaster:
Exactly, if the problem was only with the primary second than maybe it could be a regulator issue but the odds of both seconds having the same problem at the same time are astronomical.
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