Managing Task Loading - a matter of priorities

[jerryn]

for the scenario that is given us here, I would do pretty much what has been suggested. But there are a lot of situational dependent strategies.

Assume light current:

Check my own air and my buddies, signal where is the up line?

when he srudges his shoulders, start heading up. At about 50' or perhaps shallower depending on the current, send up a smb -- one only. I agree with Mike on this one.

continue a normal ascent.

I think it is important, especially if you are getting a bit low on air, to get shallow first and then worry about the smb. From 100' to 50' or 40' can be only one minute so little is lost with this, but you have nearly doubled your breathing air.

An exception would be a ripping current which could drive you too far away from the boat to be spotted. Then I would use a closed cell bag and send it up from the wreck.

In a different scenario, where you have 50 minutes of deco off of a deep wreck and some current, sending up the smb first would be the priority -- but then you and your buddy should have plenty of back gas left so the gas situation would not be a stressor, only bottom time.

Jerry

 

[android]

So doesn't it boil down to "stuff that can kill you the fastest should always get the highest priority." ?

Same as Clint Eastwood in The Good, The Bad and the Ugly, you shoot the baddest bad guy first.

 

[Diver0001]

....snip....

The first 3 steps ABC are all good, D is normally where people try to solve too many problems at once ie launch DSMB whilst playing with something else that needs fixing, not maintaining buoyancy as they ascend etc, hopefully they used the C - communication part to organise the order in which they are going to deal with the tasks at hand.

This is a good point. As the situation gets more complex you might need to run through this cycle a couple of times and you should certainly try to deal with tasks in sequence. I think the cleanest way to do this is to choose a task, do it until completed and then move on to the next task. The issue here is time pressure caused by the nubmer of task you have.

Time pressure comes in two forms. Pressure from the NDL's (or your run times) and pressure from air supply. In the scenario I mentioned a diver might be feeling pressure from both. Both you and skull mentioned ways to back off the NDL time-pressure. He would do it by ascending and dealing with the DSMB in mid-water and you mentioned that you might go a couple of minutes over and deal with it in stops -- it should be noted, however, that his solution actually solves the problem and your solution would transfer solving the problem to another task further down the chain (longer deco and maybe more time pressure based on air supply) -- these "chains" of things mounting up or getting delayed are better avoided. It's possible to get your "chain" bunched up and you don't want that.

Moving along: If you're feeling time pressure by mounting numbers of tasks then you might decide to eliminate some tasks. For example suppose that, in our scenario, we also had a line laid out on the wreck and we needed to reel it in before ascending. The time needed to to this might get us in pressure both in terms of air supply and NDL so you might need to eliminate the task and leave your spool on the bottom and pick it up on the next dive.

Similarly, another search for the upline might leave us with more time pressure in terms of NDL and maybe gas. In that case you might not have the time to deal with the DSMB on the bottom and you may need to delay this task (as skull did) until you reach your first stop. This is also a case of moving a task down the chain so I would tend to not search for the upline and deal with launching the DSMB while you still have time. That way, the task is done and out of the chain.

Practicing a set order of doing things also helps to keep your tasks sorted.

The DSMB is a special case. I mentioned in my solution that I would launch the DSMB from the bottom and I think I would do that if I were inside the NDL's and all I needed to do is control my ascent. However on a deco dive I find it much easier to delay this task until the shallow stops. That way you don't have your hands tied up with the reel while you're trying to read gauges, maintain exactly 10m/min ascent to the first stop, manipulate the inflator, make a clean first stop, make a gas switch, watch your run times etc etc. At your first shallow stop longer than 1 min you've got all that other stuff behind you and you have all the time in the world to launch your blob without it getting in the way. YYMV (Bit of a hyjack of my own thread happening here....)

The important thing is when you have a number of tasks that you know you'll need to do (or when preparing for scenarios) It's a good idea to sort them in order before hand so you don't need to think about it in time pressure.

R..

 

[simbrooks]

Time pressure comes in two forms. Pressure from the NDL's (or your run times) and pressure from air supply. In the scenario I mentioned a diver might be feeling pressure from both. Both you and skull mentioned ways to back off the NDL time-pressure. He would do it by ascending and dealing with the DSMB in mid-water and you mentioned that you might go a couple of minutes over and deal with it in stops -- it should be noted, however, that his solution actually solves the problem and your solution would transfer solving the problem to another task further down the chain (longer deco and maybe more time pressure based on air supply) -- these "chains" of things mounting up or getting delayed are better avoided. It's possible to get your "chain" bunched up and you don't want that.

I completely agree with you and the Skull about ascending being preferred, in my example, in a cave, that isnt always possible, but in OW i would certainly be all for ascending a bit if not up to a stop once anything life threatening were sorted out.

I have always been told, "there is only one real emergency, OOA, the rest you can work through".

 

[Diver0001]

I completely agree with you and the Skull about ascending being preferred, in my example, in a cave, that isnt always possible, but in OW i would certainly be all for ascending a bit if not up to a stop once anything life threatening were sorted out.

I have always been told, "there is only one real emergency, OOA, the rest you can work through".

I'm not really qualified to talk about how to apply this in a cave. I would think navigation would have it's own special needs.

R..

 

[Laser]

IMO, one marker per team is enough and more can just make a mess out of things. you don't need a line in your hand to control stop depths although a visual reference is nice.

I agree.

Getting back to the line is great but it won't help if you don't have the gas to get back to the surface. When you hit gas limits you head up even if it means landing in cuba or someplace.

Again agree

 

[Doc Intrepid]

Only two observations:

1. On many east coast wrecks if there is surge or current along the bottom the vis can be 80' or more just up off the top of the wreck, but be 15'-25' down adjacent to or inside the wreck. If you can't locate the upline, sometimes ascending 10' or so may put you in clearer water.

2. We do a lot of deco dives on wrecks in between 110' and 170'. Your original scenario included this parameter: "Amidst the confusion the current is slowly pushing you and your buddy a little over the top of the wreck and you begin to drift...". I put this exact debate to two boat captains operating out of Morehead City, NC: "Blow the bag on the wreck, or wait and blow the bag at 70' or shallower?" Both captains gave me the same response.

They said (essentially) they "watch bubbles". One said: "I can pretty well track the locations of the divers by where their bubbles are. BUT if one pair gets blown off the wreck and the seas are up, 2' to 4' or so, I may not notice their bubbles trailing away off the stern because I'm thinking they're with the others. If those divers wait until they hit 70' or 50' or whatever to send up their SMB, and they're being carried away by current, by the time that bag hits the surface it could be 100 yards off my stern. With 2' to 4' waves I'd never see it. So send that bag up as soon as you know you have a problem. Then I can watch that bag go off, maybe put a call out on the radio, and after I've got the others aboard I can come and find you."

My personal protocol is clear. If my buddy and I are blown off a wreck, we get a bag up immediately. You only need one, but let the captain know you're having a bad day and you're gonna be doing drift deco. Don't wait until you're up past your 70' gas switch to finally try to tell somebody you're gone. By that time its too late.

 

[hobodiver]

The first priority is always having something to breath and controling position...like pilots say...aviate, navigate and then communicate. Getting back to the line is great but it won't help if you don't have the gas to get back to the surface. When you hit gas limits you head up even if it means landing in cuba or someplace.

I know this is a really old thread, but I stumbled across it, and found it very thought provoking, and thought it would be useful for others to read.

Also, I wanted add one thought to this particular part of the conversation:

Generally, I agree with the "head up when low on gas" thinking, but what if you knew there was more gas waiting somewhere along the upline (like other divers and/or regs or tanks hanging from the dive boat)? Would it make sense to spend a little bit of time trying to find/get back to the upline, or would it be better to still send up the SMB?

 

[Sas]

You're diving on a large wreck in 100ft of water. The visibility is relatively poor and there is a slight current. You're down to 80 bar and within 3 minutes of the NDL when you suddenly come to the realization that you the upline isn't where you thought it was. You're disoriented, getting a little low on air and you need to leave the bottom. You have to collect your buddy, launch at least one DSMB and upon looking at your buddy he's looking stressed. Amidst the confusion the current is slowly pushing you and your buddy a little over the top of the wreck and you begin to drift a little deeper.

I thought the OP was interesting but I am wondering about a few things such as why losing the upline is a big deal? I never dive with an upline, sometimes there is a shot line but it can be removed middive if the captain feels like it. For a dive to that depth, I would swim around until I was done with the dive, ascend from whereever I happened to end up to 10m, do a 1min safety stop there where I would launch an SMB, then do another stop at 5m, then ascend to the surface. Then the boat would come get me.

Usually slackwater is over by the end of the dive when I am ascending so most of my safety stops are done drifting midwater in a current so I am curious about the need to launch an SMB at the bottom? Especially if I had a buddy that was a bit stressed or was close to NDL. I would put that last, ascend with my buddy a bit so he calmed down and then worry about the SMB. Also why would one launch two of them? And why would they be needed for stability? Anyway, I guess the scenario is foreign to me as I don't have to worry about finding an upline, but I won't always be diving locally so interested to hear more reasoning.

Someone mentioned that a captain mentioned it is helpful for them if you launch it immediately, however on dive briefs the captains were I dive request that we put up an SMB during a safety stop or deco stop unless we make it back to the shot line (though usually this is quite hard if slack water is over). So again, that is different to people's experiences here so was wondering about that...

 

[Deefstes]

Excellent thread!