Deco vs. Drift?

[O-ring]

I saw a troubling occurrence on a dive boat this weekend and I wanted to get your take on it (Mods: if this is posted in the wrong area, feel free to move it).

We were on the Lobster Wreck (AKA Porta Allegra) off Morehead City, NC. If you haven't been there, it is a really nice wreck...3 people in our group brought back lobster...the largest being about 8-9 lbs. We saw a huge sand tiger and several lion fish as well. Anyway, I digress...

The wreck lies in about 120 fsw and you will definitely hit 120 fsw as a max depth since the wreck doesn't have much relief anymore (only the boilers) and you have to get under the plates to find lobster. The first thing we noticed when we dropped in was that there was a very strong current near the hangbar. We had to really work to get to the line and although the current diminished somewhat at depth, there was still a strong current on the wreck. Vis was about 60' and temps were about 74 F top to bottom. The wreck is nicely laid out and fairly easy to navigate.

One guy on the boat, diving singles and air, had a problem on his dive. Apparently, he was away from the anchor line and not sure where it was when his computer showed him he had hit NDL. Rather than incur a deco obligation and search for the anchor line, he chose to make a free ascent from 120 fsw. I don't know if he completed his required safety stop or not (I didn't ask him), but he surfaced quite a ways from the boat and had to be helped back aboard.

What are your thoughts on this scenario? Incur the deco and find the anchor line or do a free ascent with the current being what it was?

 

[raxafarian]

shoot a bag, free ascent.

Where was his/her buddy?


We had a hell of a current on the Duane a couple of weeks ago. Plan was descend the bow line (pulling down hand over hand to 110ft) drift the wreck and catch the stern line. Told the captain if we miss the line, I would send up my bag....

If I didn't have a bag, I would be leary of drifting too far while doing a free ascent, but that's one reason to carry a bag.


If they were having a problem it was probably best to head up without the line, rather than spend more time at depth TRYING to find it...no guarantee... then if you don't find it, you'd be drifting further while doing your stops.

 

[O-ring]

raxafarian once bubbled...
shoot a bag, free ascent.

Where was his/her buddy?

I should have addressed these in the original post...good questions.

1) I don't know where the buddy was...he was one of two divers that raised their hands when the cap'n asked if anyone needed a buddy. They were supposed to be buddied up, but to my knowledge he was solo diving...this is speculation on my part, but since they only had to get one guy out of the water, obviously his buddy wasn't with him.

2) I don't think he had a bag...just a guess based on my talk with him on the way out to the site (he was sitting next to me and I asked about his camera).

 

[raxafarian]

I was editing while you were replying


to re-state: Better to head up without the line.

1. no guarantee you will find the line

2. time for stops (and therefore time to drift) increase with deco obligation

3. Single tank: possible lack of air for extended time at depth/deco




Hopefully they had (OR should have had), as a minimum: safety sausage and dive alert to try and signal the boat. I think everyone needs to carry these 2 items on any open ocean dive.

 

[AquaTec]

O-ring
it is hard to comment on this perticular situation as i wasn't there.

I would love to discuss this in the tec area

as for basic scuba, and as a basic scuba diver

I would need to consider the following

1 - boats ability to pick me up if i drift
2 - the reason he has aborted the dive
3 - vis, current, possibility of finding the line
4 - gear i have, bag, sasauge, etc.
5 - my own diving experience
6 - my knowledge of decompression procedures

I think either way has pros and cons and would depend on the situation.

 

[swimndive]

Let me see if I got this right. There was a big surface current that day, which only the divers seemed to notice when they got to the hangbar. Because of this or perhaps due to some other reasoning, the dive boat was actually secured to the wreck which was at a depth of 120 fsw. Then a single tank air diver was actually allowed to enter the water and do this dive with out any sort of plan, buddy or the requisite emergency equipment or knowledge. What should he have done? He should have bought a lottery ticket that day, he's the luckiest man alive. Sounds like a real recipe for disaster. He and his buddy should have aborted on the way down especially if they never made it to the anchor line. I'm amazed that he decided to use all his ndl time to look for the line, and I wonder also what his pressure gauge read.

 

[reefwreck]

Good points made already by raxafarian and AquaTec. The only point I would like to add is if he had a reel (which I doubt) and the current was manageable, he may have been able to rig his own ascent line attaching one end to the wreck, reeling it out as he ascends and using it as a "point of reference" as he swims against the current to keep him from drifting away from the wreck. He slowly ascends in this manner and does all stops. Assuming it is not too big a wreck, he should hopefully surface in the general vicinity of the dive boat. At the worst, it might cost him some lost reel line.

Assuming this wreck is not particularly large, and as O-ring describes:

the wreck doesn't have much relief

Vis was about 60'

The wreck is nicely laid out and fairly easy to navigate.

This diver was in over his head in more ways than one if he couldn't find the line.

 

[MikeFerrara]

IMO,
Most recreational divers have no business on that wreck in those conditions and that diver proved my point. If he hit his NDL, how much gas did he have left? He shouldn't have lost the line. He shouldn't have pushed his NDL. Anyone who incures a deco obligation with no redundancy is an idiot.

He made so many mistakes there just wasn't a graceful way out but in his case he needed to get to the surface. My guess is that if he had tried to find the line he may not have had the gas to complete the required dece wether he found the line or not.

A free ascent is no big deal if your equiped (reel and bag). Alittle extra hang time is no gig deal if your trained and equiped for it (enough gas and redundancy).

these are all contingencies we plan for and are prepared for. He wasn't prepared and he hadn't planned and he shouldn't have been there.

 

[O-ring]

To help AquaTec make up his mind:

1 - boats ability to pick me up if i drift

No inflatable on board, 65' boat, tied into the wreck. They did have an Apollo they could have used to go get you though...

2 - the reason he has aborted the dive

He was afraid of exceeding NDL, AFAIK. I don't know how much gas he had left.

3 - vis, current, possibility of finding the line

See above for all the info I have... 60' vis, pretty good current, wreck nicely laid out, mate tied a reel going from anchor line to bow and left it for the divers.

4 - gear i have, bag, sasauge, etc.

Based on my discussion with him, I am pretty sure he didn't have a liftbag/spool/reel. He may have had a sausage and a whistle, not sure.

5 - my own diving experience

He had a lot less than you . Asked me if I was nitrox certified and then asked if nitrox was air with additional nitrogen in it. Said he hadn't been on a boat with all this nitrox stuff before. Not intended to flame him, just giving you some of the context I was using to make my assumptions to fill in the facts I don't know.

6 - my knowledge of decompression procedures

See #5..

 

[WreckWriter]

He was clearly "out of his depth"....... Under the circumstances I guess he did the best possible thing. See "The Last Dive" for Bernie Chowderry's tale of what can happen if one spends too much time looking for the line....

Tom