Beware lunatic divemasters

[nimoh]

It's also possible the DMs were not in deco, but the OP was per his computer. There is a broad grey area where various algorithms and implementations can have pretty different outputs.

seems pretty clear that this was not the case, it wasn't the OP that was in 20 minutes of deco.

When our DM finally climbed aboard with a 12 year old diver in tow, they told us the story about how they went into 20 minutes of deco. So our DM took a Junior OW diver into 20 minutes of deco.

 

[Russoft]

was it really deco dives? I've heard divemasters joke about going into deco if they see something nice, but never actually did it. How close were you to deco when you called the dive? Diving on some of the walls in GC we really pushed the deco limits @ >100 feet but never actually went into deco... did add'l/extended stops @ 30-20-10 feet just in case but it was all precautionary (I wonder if another person would call that going into deco?)

I didn't see the DM's computer after the dive, but I assume they didn't do 20 minutes of deco stops for kicks. The dives weren't exactly deep relative to what I've dived before (20-27 meters), so I imagine the only ones with deco obligations were the ones with low air consumption and long bottom times.

 

[RJP]

Although I agree that running up 20 minutes of deco with non-deco trained divers (and I assume on a single tank) is pretty dubious,

I didn't see the DM's computer after the dive, but I assume they didn't do 20 minutes of deco stops for kicks. The dives weren't exactly deep relative to what I've dived before (20-27 meters), so I imagine the only ones with deco obligations were the ones with low air consumption and long bottom times.

It's essentially impossible that either the DM or the Jr OW diver had enough gas with them to spend enough time at 24m to rack up 20 min of deco.

According to V-Planner, a diver with good air consumption diving 21% would need to spend 50 minutes at 24m to rack up 20min of deco. V-Planner further says that such a diver would need 134cf of gas to complete such a dive. Not going to happen on a single tank dive... I don't care HOW GOOD your consumption rate is.

 

[BRT]

Russoft, we spent a bunch of time hanging above this guy because we were trying to preserve air or getting too close to deco. You still are responsible for yourself. I remember spending evenings playing chess with another shop owner. He would ask where we had gone and what we had done that day. When we told him he would respond "very dangerous!". The chess player is still running a dive shop and still hates to dive. It is just a business for him. I like to talk to him but I don't dive with him.

 

[phoenix31tt]

According to V-Planner, a diver with good air consumption diving 21% would need to spend 50 minutes at 24m to rack up 20min of deco. V-Planner further says that such a diver would need 134cf of gas to complete such a dive. Not going to happen on a single tank dive... I don't care HOW GOOD your consumption rate is.

this is what i'm saying myself... that's why i asked the OP to clarify how much no deco time HIS computer showed him as he indicated he surfaced early to avoid going over the NDL...

how long was your dive and at what depth?

 

[TSandM]

RJP, we have to consider that it might well not have been the first dive of the day, and from the story, certainly wasn't the first dive of a series of days. Some computers get downright parsimonious on bottom time when you've got some residual nitrogen on board.

However, I think being able to rack up 20 minutes of deco AND do it on a single Al80 is pretty unlikely, and very stupid.

 

[The Chairman]

Why question whether they were in deco or not? They were there and you weren't. I'm going to go with the eye witness on this one. I bet they were diving a Suunto PDC at that. Easy to rack of lots of deco on air on one of those.

 

[phoenix31tt]

Why question whether they were in deco or not? They were there and you weren't. I'm going to go with the eye witness on this one. I bet they were diving a Suunto PDC at that. Easy to rack of lots of deco on air on one of those.

Because that's what I do when some parts of a story seems weird... the "EYE" witness wasn't an eye witness at all.. he "heard" they were in deco... they "say" they would go into deco if they saw something nice... That's why i'm asking what did his computer show... not there's. He doesn't know if they were really in deco or not. Since he says he aborted the dive prematurely so he wouldn't go into deco i'm expecting to hear he was close to it... If i don't have two sides of a story i like to make sure the one side i have makes sense

 

[The Chairman]

Because that's what I do when some parts of a story seems weird...

Interesting. What's 'weird' to you, sounds quite reasonable to me. Many are quick to second guess others. I'm sure that there are all sorts of reasons, but it just comes across as petty and self serving.

 

[Nemrod]

I try to take people, even strangers at their word, until proven otherwise. I bump into deco regularly on an aluminum 80 even on nitrox. Of course as soon as I see and anticipate it about to happen, I move up in the water column. I was on the Spiegel just a week and a few days ago, definitely went into the deco but I also moved up immediately and by the time I reached the mast the boat was to and reached 60 feet, did a stop and it cleared into the yellow, by the time my 3 minute safety stop completed I was green on the bar. I consider this to be routine. If push came to shove and I wanted to get bent I am quite sure I can do it with an 80cf tank and then some. Of course that would be very stupid.

If a diver, like our OP does not understand or agree with the dive plan, again, the time to discuss that is before the dive. I realize though that unexpected things happen. More than once I have been told we are going to do blah, blah and not drop below max of 100 feet blah and immediately saw the guide at 130 plus. Years ago I told my wife to stay with the guide, in Cozumel, I was infatuated with my new Nikonos III, I looked around, after being told we would stay above 100 feet and sure enough he and my wife were at a good 150. I nearly had my head explode I was so mad and rushed down and grabbed her up. Now I tell her to stay with the guide if I leave her a minute but I also give her our own briefing and max depths and turn times etc.

It is good the OP questions these things, I would probably do the same. Some places are indeed known for "cowboy" diving. We want to have fun, not get hurt and spend our vacation in a chamber (do they have a chamber?). Cowboy Diving, Yahooooo, then have a cowboy in SCUBA riding a deco computer graphic, you know that would make a good tee shirt, a few nice ideas lately.

N