Dr. Lecter
Contributor
Or just a couple button-presses on a Shearwater. 
ing tap interface 
ing tap interface 
Emergency Descent During Deco
- Thread starter dumpsterDiver
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
MalibuJerry
Contributor
Dr. L, that is correct if...The Shearwater is working correctly and you are not just adding task loading to an emergency situation. But you are diving quickly to get out of the way of a boat, you have a regulator dangling and who knows what else is going on, perhaps a wicked current? I would start with Centrals ratio deco (depending on the depth of my dive -- perhaps 3:1 if a deep dive) and then when the ship is passed begin my ascent, or blow another bag and then begin my ascent. I can always return to my computer for confirmation of my decision, but I don't have to be tapping while I could be doing other things. The point is, one should be prepared to use the computer between the ears as a first resort as it diminishes task loading and therefore increases safety.
lindenbruce
Contributor
In this scenario if you had to ditch your first SMB/reel for fear of it becoming snared by the offending ship to dive down to avoid said ship that's about to turn you into a bug on it's bow, you will have a second bag/reel to help complete your deco and signal your attending boat of your location once you resume said deco. B.
The reality is that if you are using a computer OR tables to control your dive/ascent, you will be in complete breach of the built-in algorithm by suddenly making a radical deviation from the plan. I think there's a very good chance you'll end up on oxygen and then in a chamber, but that's still preferable to the alternative in the cited scenario.
I watched a diver do something very similar some time ago, having run pretty well up to the limits on a recreational dive he dropped back to maybe 50ft from his final stop ("safety stop") to photograph something he'd just spotted on the bottom. That was a costly mistake. He returned home about a week later than he had planned, and some $40k poorer. He hadn't thought he needed dive insurance - he was wrong.
---------- Post added July 12th, 2013 at 09:00 PM ----------
Your comment was far from a general one. You implied that using a computer was a cop-out and a real "tech" diver wouldn't need/use one. That is supreme arrogance. Whatever a "tech" diver is, (s)he should be equally comfortable in either case, but interested in using a computer because of the greater flexibility it permits. I was using myself as an example of many experienced divers out there - I have neither the need nor the desire to justify myself on a message board.
I watched a diver do something very similar some time ago, having run pretty well up to the limits on a recreational dive he dropped back to maybe 50ft from his final stop ("safety stop") to photograph something he'd just spotted on the bottom. That was a costly mistake. He returned home about a week later than he had planned, and some $40k poorer. He hadn't thought he needed dive insurance - he was wrong.
---------- Post added July 12th, 2013 at 09:00 PM ----------
Your comment was far from a general one. You implied that using a computer was a cop-out and a real "tech" diver wouldn't need/use one. That is supreme arrogance. Whatever a "tech" diver is, (s)he should be equally comfortable in either case, but interested in using a computer because of the greater flexibility it permits. I was using myself as an example of many experienced divers out there - I have neither the need nor the desire to justify myself on a message board.
You know, I belong to the "no computer" group of technical divers. I think you should have enough of a plan that you don't need an "on the fly" device to sort things out for you; if you are using "on the fly" mental computation, it pretty much requires you to keep your dive within some narrow parameters.
But the places where I think computers are useful are places like this -- where an unforeseen and possibly unforeseeable event occurs which requires a truly significant deviation from any kind of normal profile. I THINK I understand deco well enough to incorporate a deviation like this into my plan, but I wouldn't be a bit unhappy to have the backup of a device capable of doing iterative calculations much faster than I can, to make sure the answer I come up with is at least somewhat rational.
(Wild up and down cave profiles are another place where I think computers are probably a good idea.)
But the places where I think computers are useful are places like this -- where an unforeseen and possibly unforeseeable event occurs which requires a truly significant deviation from any kind of normal profile. I THINK I understand deco well enough to incorporate a deviation like this into my plan, but I wouldn't be a bit unhappy to have the backup of a device capable of doing iterative calculations much faster than I can, to make sure the answer I come up with is at least somewhat rational.
(Wild up and down cave profiles are another place where I think computers are probably a good idea.)
Dr. Lecter
Contributor
I was just poking fun at a poorly executed 'innovative' interface. If I have to drop from my 10' stop to 100' because I realize I'm in/near a shipping lane and something big seems to be heading my way, the very last
I'm going to give will be about my computers' gas settings, much less adjusting them. I'm going to vent my wing, spit my deco reg, and stuff my bungieed backup in my face just as fast as I can--the computers can scream about pO2 all they want on the way down, and screw the pooch slightly on their nitrogen loading calculations, too, for all I care. Once I'm down where I want to be, I'll worry about setting the computers properly, think about what just happened and how I can best correct for it within available gas limits, and then see if the computers agree with my estimates. I may even break out the wetnotes and scratch out some math while doing my Das Boot impression...though I can't imagine having to stay deep long enough to seriously alter my deco schedule.
Hello, I said in my first post that I myself use an X1 - so according to you, I'm saying I'm not a real tech diver??
What I actually said was that if you can't do a tech dive without a computer, you weren't trained properly. Not that you shouldn't use a computer, or that you're not a tech diver if you do use one.
You then went on to tell me you've done more tech dives than I have dives /golf clap
Supreme arrogance would be inferring something that wasn't implied and not considering you might be wrong
Dsix36
Contributor
- Messages
- 1,701
- Reaction score
- 1,490
This question is really a no brainer for me. If it was a matter of getting hit by a boat (or propellers) or diving back to depth, my butt will be descending without having to think about it. Consider this - what are your probabilities of survival after getting chopped up by a spinning propeller? What are your odds of surviving another deep descent (even if you get bent)? My preference is to take a chamber ride!
I am not saying this without some form of merit. Recently during my 20 deco hang after spending 40 minutes at 170', our anchor line snagged on something below. With about 20 minutes of deco left, I decided to go back and release the line. I know that if I surfaced we would need to kill a lot of time before I could go back down and figured that my deco penalty would be a better option. I descended to 110' for another 5 minutes to deal with the line. I was only penalized by an additional 8 minutes of deco and suffered no ill effects.
Now, I know that the next time might very well get me bent and I will never tell another to take such a chance, but I still think getting bent is better than getting run through a blender.
disclaimer - I use a rebreather, so gas switches and gas volume is not a concern.
I am not saying this without some form of merit. Recently during my 20 deco hang after spending 40 minutes at 170', our anchor line snagged on something below. With about 20 minutes of deco left, I decided to go back and release the line. I know that if I surfaced we would need to kill a lot of time before I could go back down and figured that my deco penalty would be a better option. I descended to 110' for another 5 minutes to deal with the line. I was only penalized by an additional 8 minutes of deco and suffered no ill effects.
Now, I know that the next time might very well get me bent and I will never tell another to take such a chance, but I still think getting bent is better than getting run through a blender.
disclaimer - I use a rebreather, so gas switches and gas volume is not a concern.
w ripley
Contributor
FWIW, I've done a ton of tech dives on OC, down to 385 fsw. Cut tables & used a BT. Totally agree you don't need a computer to tech dive.
However, when I went to my RB it came with 2 handsets, both with computers. I've been diving that way for the last 6 years.
Bottom line (for me): Having dived both ways, I prefer using computers. Still cut tables and have them and a BT in my pocket, but computers are the tool to have when the unexpected happens. Real-time PPO2, depth & mix calculations offer options.
However, when I went to my RB it came with 2 handsets, both with computers. I've been diving that way for the last 6 years.
Bottom line (for me): Having dived both ways, I prefer using computers. Still cut tables and have them and a BT in my pocket, but computers are the tool to have when the unexpected happens. Real-time PPO2, depth & mix calculations offer options.
Similar threads
