Sharing a Dive Computer

[Sas]

So basically what I'm hearing in this thread is NEVER, EVER dive without a computer?

I wouldn't agree to this. I have seen people forget their computer and do dives anyway. The dives were shallow and NDL was not ever going to be close. It depends on the situation really.

It's not ideal but I would do this if I forgot my computer and wasn't going to be anywhere near decompression, just to get the run time and depth! But yea, there are a lot of dives where it is really best to have your own way of checking depth and time (not necessarily a computer, I could get by quite well these days with my computer in gauge mode) so try to get another computer as soon as possible or at least a depth gauge/timer and then dive according to tables.

 

[Notso_Ken]

New diver here, my wife and I are just finishing up our PADI OW and have scheduled a trip to Belize - we're also just getting started on our equipment purchases. We just bought a Suunto Gekko dive computer that we're hoping we can share to start out. Since we will be doing all of our diving together I suspect that while not ideal that this isn't too big a problem. Any things to be wary of or to take into account when sharing a computer with your dive partner? I plan to be conservative on the numbers to ensure there are absolutely no issues.

What's wrong with planning your dive using the tables from whatever agency you have tables for, and dive the plan. No need for any unreliable computers (at least according to some of the posts on here you'd think they're unreliable).


Ken

 

[Mike Boswell]

When it comes to breaking a rule I always ask myself two questions:

First, did the people who made the rule know more than me?

Second, what is the risk/reward ratio?

For the first question, I doubt anyone would dispute that the diving experts and scientists and engineers at PADI and Suunto know a lot more than me.

For the second question, the only thing to be gained by breaking the no-sharing-computers rule is a few hundred bucks, and the thing to be lost is obvious.

 

[LeadTurn_SD]

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?

Good points Peter.

Regarding sharing computers: I understand the basic reasoning behind "Each Diver Must Have Their Own Computer"... but with the right buddy pair or "team" I have no problem when in a recreational, shallow, NDL setting violating that "rule" (and have done so without concern on every dive for the last two years since returning to diving).

Each diver needs a depth gauge and timing device, but not necessarily a "dive computer" that is tracking their nitrogen loading.

I do think where it becomes risky is on repetitive, multilevel dives that begin to approach NDL's, especially on the 2nd or 3rd dive following "short-ish" surface intervals.

The "square-profile" tables will not have credited the multilevel profile of the previous dives, and the diver(s) using tables-only will be forced to either dive a "trust-me" dive following the diver with the computer, or follow their tables and significantly curtail the depth and time on the 2nd and 3rd dives.

Best wishes.

 

[LeadTurn_SD]

What's wrong with planning your dive using the tables from whatever agency you have tables for, and dive the plan. No need for any unreliable computers (at least according to some of the posts on here you'd think they're unreliable).


Ken

Nothing at all wrong with using tables-only.

The potential problem comes on a dive charter when you mix "square profile" table users with dive computer users on a trip with deep multilevel dives.

The dive computers will credit you for the time spent at shallower depths during the multilevel dive, and the tables will not. This often results in less "bottom time", especially on the 2nd and 3rd dives, or even on the 1st dive if it starts fairly deep then moves to shallower levels.

Best wishes.

 

[halocline]

On guided dives in the caribbean, divers share computers all the time. Typically this is happens with divers using rental equipment that does not have a computer, they simply follow the DM, and don't exceed his depth/time on the dive. A competent DM in this situation will avoid any sort of profile that pushes the limits.

This is only safe, of course, if the profile of the dive is WELL below any NDL concerns. Likewise for ascent rates; since computer alarms can be very helpful to new divers especially, if you dive without one, you have an increased challenge in monitoring and controlling your ascents.

Safe dive profiles are the same regardless of computer use. Multi level planning can be easily done on the wheel; if you can still find one.

The irony is that the divers that have enough experience and control to plan and execute safe profiles are likely to be the same ones that either own computers or have done extensive dive planning with multi level tables.

I can see why the agencies don't allow dive computer sharing, but that doesn't mean that it's inherently dangerous. Diving deep, pushing NDLS, and ascending fast are dangerous. Using a computer is supposed to help you avoid those behaviors, but there are other ways of doing that.

 

[The Chairman]

It's apparent PDC wasn't covered

That is not apparent. The rest is a simple reiteration of the previous arguments (ad nauseum) and only augmented with another series of ad hominem attacks.

To recap my position:
If your buddy skills are reasonable.
If you follow my earlier caveats.
Sharing a PDC is preferable to missing dives.

This is true for a couple only able to afford one PDC or for anytime a PDC craps out during a dive leaving only one in your buddy team.

Of course, if your buddy skills are less than reasonable, you should be working on that anyway.

 

[syntaxerrorsix]

Well add nauseum is certainly a suitable sentiment. Feel free to justify poor ideas all you like. Know for sure I will point them out every time you do. Have a great day.

 

[hbhobby]

I can say that when I started diving I had no depth gauge or SPG or BCD, just a regulator backpack and a J-valve, so I will agree with the "is it possible yes is it preferable no" side of the argument here. we dove for years (and I am still alive) without the all of the "stuff" we have today. it is MUCH safer today that when we would wing it! do I recommend diving "sharing" a computor no, but like previously stated that is essentially being done by ending the dive when the first computor says to end.

 

[The Chairman]

From Divenewswire...

SSI Moves Dive Tables in the Open Water Diver Student Manual

SSI Provides the Ultimate in Diver Training

Fort Collins, CO January 2010. Scuba Schools International (SSI), the premier scuba education and business support company announces their decision to move the dive tables to the Appendix in their SSI Open Water Diver Student training materials.

"Just like technology has entered our daily lives with the many advancements at our disposal — i-phones, laptops, etc. — dive computers have also become mainstream in recreational diving. For this reason, SSI has chosen to focus on the use of dive computers in our Open Water Program," stated Doug McNeese, SSI President and CEO.

McNeese continued, "We are not eliminating dive tables from the manual. We are simply placing them in the Appendix. This will allow Dive Centers and Dive Professionals the option to use the tables if they choose."

For the past 2 years, SSI has given Dive Centers and Professionals the option to train with either dive tables or computers. We moved the tables to the index and left the information on the DVD so that divers will still have the information.

The dive tables can still be used as another way to help students understand how we absorb, eliminate and track nitrogen. Then students will have the knowledge they need to complete their recreational dives with a computer.

SSI will continue to bring you these types of innovations to help you stay on the cutting edge of training and education.

“SSI, Where Your Business Comes First”

So now, there are at least three agencies which prefer to teach PDCs over tables: SDI, PADI and now SSI. Knowing tables is no longer a given. Now, I wonder what the standards are for classes for PADI and SSI are?