lamont
Contributor
This goes along with my previous post on failure combinatorics. What do you need to be thinking about during an ascent?
First thing is that you'll probably lose 3 posts. The failures may be what cause you to thumb the dive, blow a bag and ascend, or they may occur on the ascent. But the worst that happens is that 3 posts are gone. Usually, one diver OOG and another diver without a post. The fastest way to setup an ascent drill is to drop down (doing 1 minute stops every 10 feet on the ascent for practice) and then *bam*, *bam* get an OOG and a valve failure. Not terribly realistic, but it gets the team down to minimum resources and forces an immediate ascent.
After dealing with the failures, you need to get a bag shot if you do not have an upline. The least task loaded person (probably the diver not involved in an OOG) should shoot a bag. The team ideally needs to shoot the bag on the fly as deco is being called and the team is starting the ascent. With good awareness and buoyancy control there shouldn't be any need to shoot the bag while sitting on the bottom. The bag should be shot fast enough that its not an issue by the time the gas switch comes around. While the diver shooting the bag is task loaded the other divers (probably the OOG donator) needs to be calling deco. Someone always needs to be calling deco, and if you're not task loaded that person is You -- doesn't really matter what the plan was at the surface if the designated deco person is shooting the bag they'll be needing some help with calling deco...
On the ascent itself and timing deco, 1 minute stops means that you are leaving each depth 1 minute apart. 30 second slides and 30 second stops are one way of achieving this. 45 second slides and 15 seconds stops also acheive it. A 60 second slide means you keep moving as soon as you hit your stop depth and start moving. I've also been told that if you run over my 15 seconds on a stop (1:15) you can truncate the next one to 45 seconds to get back on track (obviously there's a limit to how much you can fudge things like this and not totally screw up your deco). As practice dropping down to 30 feet doing 30 second slides and 30 second stops and then ascending should take:
30 seconds to 10
30 seconds at 10
30 seconds to 20
30 seconds at 20
30 seconds to 30
30 seconds at 30
30 seconds to 20
30 seconds at 20
30 seconds to 10
30 seconds at 10
30 seconds to surface
= 5 minutes 30 seconds total dive dive
Once you get to your gas switch the diver with the most problems needs to switch first. OOG divers have the most issues, followed by unfixable manifold failures, followed by post failures. Switching needs to be quick, but precise. Pass the spool off to a diver not involved in a gas switch. After the OOG diver does a switch, the donator will need to clean up their long hose, so its better to have the other diver (probably with a valve failure) switch next. Watch the line during the gas switch in particular since it likes to find its way around manifolds (line is both crucial to our survival but completely toxic when it gets too close to our equipment -- it needs to be kept an arm's distance away).
Following that, do your stop and cleanup and get moving again.
Again, there is a limited amount of things going on during an ascent and none of it should be very surprising, all of it can be visualized beforehand -- then the occasional surprise can be adapted to.
So, in summary:
- deal with the critical failures
- keep the deco moving (be fluid on who calls it)
- establish an upline
- efficient gas switch
That is about all that is needed to exit the water and live to dive another day.
First thing is that you'll probably lose 3 posts. The failures may be what cause you to thumb the dive, blow a bag and ascend, or they may occur on the ascent. But the worst that happens is that 3 posts are gone. Usually, one diver OOG and another diver without a post. The fastest way to setup an ascent drill is to drop down (doing 1 minute stops every 10 feet on the ascent for practice) and then *bam*, *bam* get an OOG and a valve failure. Not terribly realistic, but it gets the team down to minimum resources and forces an immediate ascent.
After dealing with the failures, you need to get a bag shot if you do not have an upline. The least task loaded person (probably the diver not involved in an OOG) should shoot a bag. The team ideally needs to shoot the bag on the fly as deco is being called and the team is starting the ascent. With good awareness and buoyancy control there shouldn't be any need to shoot the bag while sitting on the bottom. The bag should be shot fast enough that its not an issue by the time the gas switch comes around. While the diver shooting the bag is task loaded the other divers (probably the OOG donator) needs to be calling deco. Someone always needs to be calling deco, and if you're not task loaded that person is You -- doesn't really matter what the plan was at the surface if the designated deco person is shooting the bag they'll be needing some help with calling deco...
On the ascent itself and timing deco, 1 minute stops means that you are leaving each depth 1 minute apart. 30 second slides and 30 second stops are one way of achieving this. 45 second slides and 15 seconds stops also acheive it. A 60 second slide means you keep moving as soon as you hit your stop depth and start moving. I've also been told that if you run over my 15 seconds on a stop (1:15) you can truncate the next one to 45 seconds to get back on track (obviously there's a limit to how much you can fudge things like this and not totally screw up your deco). As practice dropping down to 30 feet doing 30 second slides and 30 second stops and then ascending should take:
30 seconds to 10
30 seconds at 10
30 seconds to 20
30 seconds at 20
30 seconds to 30
30 seconds at 30
30 seconds to 20
30 seconds at 20
30 seconds to 10
30 seconds at 10
30 seconds to surface
= 5 minutes 30 seconds total dive dive
Once you get to your gas switch the diver with the most problems needs to switch first. OOG divers have the most issues, followed by unfixable manifold failures, followed by post failures. Switching needs to be quick, but precise. Pass the spool off to a diver not involved in a gas switch. After the OOG diver does a switch, the donator will need to clean up their long hose, so its better to have the other diver (probably with a valve failure) switch next. Watch the line during the gas switch in particular since it likes to find its way around manifolds (line is both crucial to our survival but completely toxic when it gets too close to our equipment -- it needs to be kept an arm's distance away).
Following that, do your stop and cleanup and get moving again.
Again, there is a limited amount of things going on during an ascent and none of it should be very surprising, all of it can be visualized beforehand -- then the occasional surprise can be adapted to.
So, in summary:
- deal with the critical failures
- keep the deco moving (be fluid on who calls it)
- establish an upline
- efficient gas switch
That is about all that is needed to exit the water and live to dive another day.
