Diving off another's computer

[Crazy Fingers]

Of course the general rule is not to use another's computer. But the other day I found myself in a situation where I felt it was okay to have others dive off of mine since they didn't have any. (Sadly, these people didn't even have a watch or timer....) We were in an "OW cavern", and I was first in to the water and stayed deeper than the others at all times. I couldn't see how they could accumulate more nitrogen than me, so I took on the responsibility of when to tell everyone else to surface so that my partners could actually dive.

What do I think? I think it was safe but those guys need to get at least a bottom timer! What do you think and why?

 

[sasscuba]

I dived for years off my dads computer when I was younger. Always stayed 5 feet above him and to his side. Not ideal but it worked and I am still here.

 

[miketsp]

Of course the general rule is not to use another's computer. But the other day I found myself in a situation where I felt it was okay to have others dive off of mine since they didn't have any. (Sadly, these people didn't even have a watch or timer....) We were in an "OW cavern", and I was first in to the water and stayed deeper than the others at all times. I couldn't see how they could accumulate more nitrogen than me, so I took on the responsibility of when to tell everyone else to surface so that my partners could actually dive.

What do I think? I think it was safe but those guys need to get at least a bottom timer! What do you think and why?

In principle yes, however I have seen situations where two divers had identical computers and the one that was always shallower showed less remaining bottom time and required a longer SIT to obtain similar dive planning for the second time.
With computers like the Suunto range the algorithm will penalise you for fast ascents so if the shallower diver is only a little shallower and has poor buoyancy control thus subject to similar N2 loading but keeps doing fast ascents with more propension to micro-bubble formation.....

 

[Charlie99]

Although it doesn't have the stamp of approval by the certification agencies, your reasoning is correct. As long as they are at the same depth or shallower than you, your computer will be more conservative than their actual N2 loading.

In general, though, "trust me" dives are a bad idea. The others were relying upon you for controlling their deco status, when they should have at least bought a cheap waterproof watch and used tables.

 

[spectrum]

What do I think? I think it was safe but those guys need to get at least a bottom timer! What do you think and why?

Well you all took a chance and as mentioned your logic is valid. The mention of the depth consistency (buoyancy control) is an interesting twist.

Question... I am assuming that this dive profile did tease the NDL hence the "need " for a computer though the others had no timers. With their well being in your hands were you diving a table plan as a back-up and did you have a back-up timer?

I would defer diving with them until they are prepared to assume control of their own dives and get in a position to be mutually supportive as a back-up.

Pete

 

[tkdawg]

I would still make them use the tables, using your bottom time. Yes they do need some way to track time if they don't want to buy a computer.

 

[bradshsi]

Reading it I found myself wondering why your diving partners didn't have a watch or timer. Presumably they didn't have one due to lack of organization/planning or cost ? Neither is a good reason IMO. Diving is not a hobby for the disorganized or the corner cutter. Both approaches roll Mr Murphy's dice rather more than I would personally be comfortable with.

Assuming they stayed above you all the time and were in the water for less time, your computer times were probably ok. But from the sounds of your post there were at least two people diving with you.

How can you be sure they were both above you all the time ? I know from divng threesomes that keeping tabs on both partners is very difficult. What if one of them had got separated ? Did they know to go straight to the surface in that instance ? What if one of them had trouble with buoyancy and dropped below you for a significant period of time. Would they still be ok ?

Too much "trust me" for me I'm afraid.

 

[Dive-aholic]

What if something happened to your computer? Or to you during the dive? Then what? They shouldn't be diving if they don't have the proper equipment. Dive computers aren't necessary, but they should be able to at least keep track of their dive time and work the tables. Bad move on everyone's part. Especially in a cavern.

 

[dmmike]

IMHO, I feel you took on way to much risk:shakehead , in addition to what Dive-aholic said. What would you do if something happened to one of them. As we all know, there is still much to learn about DCS. If by some freak chance somebody takes a hit, where do you stand, legaly, because of your assumed role in dive leadership.

I've been asked and have said NO. It's not easy, but..............

 

[Crazy Fingers]

What if something happened to your computer? Or to you during the dive? Then what?

I guess if my computer took a dump I'd immediately call the dive and everyone would surface after a guestimated safety stop (which admittedly is very difficult to judge, at least for me.) If something really bad happened to me while diving, I would hope that breaking the NDL would be least of my partners' concerns... although you never know

As for legal implications if they got bent, I never really thought about it. I guess I believe too much in the justice system. :huh: