Sharing a Dive Computer

[syntaxerrorsix]

For those of you who are adamant that it is dangerous for a buddy pair to "share" a computer, will you please explain why it is dangerous?

Is it because:

a. One buddy doesn't have depth/time gauge? If she did, would it be OK?

If she monitored depth and time and could use that information to determine her SIT and repetitive dive with then yes.

b. One buddy won't know her decompression status?

The dive plan really takes care of that, another good reason each diver should have a timing device. Of course the likely scenario is new divers just fly the computer and ignore dive planning.

c. Do you believe that the decompression algorithms used by "recreational computers" are precise enough to actually indicate a bright line between having a strong chance of DCS vs. a very minimal chance of DCS?

After a few repetitive dives at different depths and times it could present a problem. Likely? Probably not but once again it only detracts from a point of risk assessment.

d. Do you believe it is ever safe for a buddy team to dive without any computer and without planning a table based dive? If so, under what conditions?

Absolutely, a good dive team with strong buoyancy characteristics and a good sense of overall awareness most certainly could. Is this common in a new divers? No. Is it better? No. Is it safer? No. Would I recommend it over the majority of the industry standards? No.

In my opinion it's unnecessary risk that doesn't have any benefits. It reduces redundancy in the dive team and detracts from what the diver learned from their instructor and agency.

 

[redacted]

At best, it becomes a "trust me" dive. That is, a dive where at least one of the divers does not have full control over his or her dive unless you are diving arm in arm. Beyond that, sharing the information from one computer is manageable, at least for a while. How long of a while depends on how closely one diver follows the other diver's profile. My wife and I stay fairly close but there is always a difference. Almost all the time, the difference is small and predictable. She is almost always next to me or not more than 5 ft above and next to me. (Yet, on rare occasions, I have found her noticeably below me.) I log our "ticks" on our Oceaniic computers (older models with 12 green ticks and 3 yellow ticks). We are usually the same for the first couple dives and then I run one tick more than her for the remainder of a trip. Should her computer fail, we would have no problem finishing our dive on my computer. Should her's fail, I'd have no problem finishing on hers but staying a bit on the conservative side.

I would not hesitate to finish a dive sharing a computer with my wife. While I'm sure it could be managed, I don't see us ever starting a dive in that mode. For one reason, I always carry at least one spare computer in a trip.

My interpretation of the "book answer" of follow the more conservative computer is that it has nothing to do with brand or algorithm, just follow the computer that is giving the more conservative answer (least NDL) at that moment.

For those of you who are adamant that it is dangerous for a buddy pair to "share" a computer, will you please explain why it is dangerous?

Is it because:

a. One buddy doesn't have depth/time gauge? If she did, would it be OK?

b. One buddy won't know her decompression status?

c. Do you believe that the decompression algorithms used by "recreational computers" are precise enough to actually indicate a bright line between having a strong chance of DCS vs. a very minimal chance of DCS?

d. Do you believe it is ever safe for a buddy team to dive without any computer and without planning a table based dive? If so, under what conditions?

 

[RJP]

For those of you who are adamant that it is dangerous for a buddy pair to "share" a computer, will you please explain why it is dangerous?

Sort of like the thread the other day about diving in general:

It's not "dangerous" but it is "risky"

 

[NCadiver]

Nor should you be discouraging them from diving! :homealone:

I am not discouraging them from diving only bad habits. And as a dive professional you should have recommended renting a computer or both use tables. I think even sdi say all dive need to monitor their own depth time and air with their own gauges.

oddible it fine to use two different algorithms just use the most conservative one so you don't have to do a deco stop or it lock up for violating the stop.
Thier are other threads about algorithms but both the oceanic and suunto,mares,uwatec have good algorithms.

 

[The Chairman]

Dude, now you're the one spreading myths and using scare tactics!

The issue is that each diver has his own timing/depth device. Noone suggests that all divers must use the same brand and algorithm!

No scare tactic here... they are a buddy team. They should rely on the most conservative PDC. The Gekko will be the one to go by between those two.

I have seen people disregard the more conservative computer and go with the more liberal one. It's just like diving with one PDC.

 

[The Chairman]

At best, it becomes a "trust me" dive.

With reasonable buddy skills, this is not even close to a "trust me" dive. It is a trust the PDC dive... does it matter whose arm it's on? Not really.

 

[The Chairman]

OK ok ok. Please stop, I'm really unhappy with the rising tension in this thread.

There is no name calling, just a lot of passion. That's some GOOD drama here on the Net. Hopefully, you have learned something of value in the process. Only YOU can/should decide on your comfort level. The same goes for your buddy.

 

[DiveNav]

OK ok ok. Please stop, I'm really unhappy with the rising tension in this thread......

Don't worry .... afterward they will have a drink together

Alberto (aka eDiver)

 

[syntaxerrorsix]

Don't worry .... afterward they will have a drink together

Alberto (aka eDiver)

And I'm bringing this

Hopefully Doc's up for IPA.

 

[rstofer]

OP -- THE "book answer" to this question (with a nod to NetDoc) is "Do not share" a dive computer. Interestingly enough, however, the "book answer" to the question of "Which dive computer should my buddy and I follow when buddies have different computers?" is "the most conservative computer." Pray tell, how is that different from the team diving one computer if the book answer is to ignore your computer (if it is not the most conservative)?

I think it is different in the sense that if the most conservative unit crashes, there is still a redundant, albeit less conservative, unit to get the divers home. Even the least conservative computers aren't known to kill divers. Maybe you take the personal prerogative to terminate the dive immediately, ascend in accordance with the surviving computer and then hang our at 15' for a while. But at least you have some numbers!

I come from a highly regulated industry (nuclear power) and worked in the electrical and general construction side of the facilities (not the power plant, the factory). One thing I learned early on: if the manufacturer says do it a certain way, do it that way. In fact, the National Electric Code (which has absolutely nothing to do with diving) actually states very clearly that manufacturer instructions must be followed.

I view the dive computer the same way. The manufacturer has a stated position (no sharing) and all but one agency has the same position. More important, the agency I trained with (before there were computers) is in the 'no share' camp. There is no way I want to explain how come there was an incident because I decided to do it a different way.

Do I think it can be done? Sure, by someone else. But I'm not going to be the one to recommend it and I'm not going to try it. There's no need, we all have computers.

Richard