Sharing dive computer

[Exxilon]

Hi there,

Long time lurker. Tried to find an answer to my question but couldn’t find it through searching the forum. So I’ll try it through a post here.

I will be diving alternating days with my partner. One looks after our kid while the other goes diving for a day. We’ll do three dives a day in Komodo for 10 days total without hitting NDL’s. Just recreational dives no tech or 40m+. We both have a dive computer but only mine has a integrated air transmitter. We’ll be travelling light and only bring one BCD and regulator set.

I want to leave the analoge air gauge at home because it weighs a bunch and only use my AI transmitter. Is it possible to lend my partner my dive computer when we dive alternating days? I don’t want to compromise my next dive day. I don’t see any problems but I rather hear from the more knowledgeable divers.

Modern diving computers will track "multiple dives" over several days.

Sharing the computer in the way you are proposing will be "safe" for both divers but it will result in shorter NLD's

 

[DiveLikeAMuppet]

The computer will “offgas” overnight so there should be no problem, worst case one of you might see mildly shorter no-stop time. Just don’t share it on the same day, that would actually be dangerous.

Try it yourself. Plan few dives, stick in 12 hours surface interval and see that it doesn’t really impact your no-stop time at all, not at these depths.

Same situation when you rent a computer from a dive shop - someone might have used it the day before, doesn’t matter.

If I were you, I would take an SPG too (get one without the funny console and clip it to a D-ring) and the second computer, in case that something breaks. Or at least the second computer as you could rent an SPG.

 

[Exxilon]

The computer will “offgas” overnight so there should be no problem, worst case one of you might see mildly shorter no-stop time. Just don’t share it on the same day, that would actually be dangerous.

I'm not sure I follow your logic. Two divers sharing one computer on multiple dives per day should result in progressively shorter calculated NDL's.

How did you reach the conclusion that this would be dangerous?

 

[DiveLikeAMuppet]

View attachment 867072
Red Flag!!!!

Not safe. As was said earlier, you could have your dives cut short based off what your partner did the day prior. You could end up being locked out because of it. With the lack of info about the gear, as a divemaster, I would be suggesting only one person per computer. Your profile will be different from the other person. Just not a safe situation.

As a DM, you get 4-6 people diving a random mix of computers, with a random mix of decompression algorithms, with a random mix of “conservatism” settings that half the group doesn’t understand, at least one diver didn’t read the manual for their brand new computer and at least one diver programmed a nitrox mix.

Someone having that 1% extra saturation on the computer from previous day is really the last thing that should worry you . Also, there are divers who might not dive alternative days, so unless OP hires a private DM, they would still be limited by the other divers (that little saturation that didn’t clear overnight).

 

[DiveLikeAMuppet]

I'm not sure I follow your logic. Two divers sharing one computer on multiple dives per day should result in progressively shorter calculated NDL's.

How did you reach the conclusion that this would be dangerous?

It’s not. Someone else mentioned it is.

 

[The_Menn]

Thank you all for the replies and lively discussion!

I thought I didn’t leave out any information but seeing some comments I did.

I’m bringing a Suunto Eon Core with pod and my partner has an Aqualung I330R. I didn’t change any settings on both computers so everything is on factory setting.
Our reason to not bring an SPG is weight as mentioned before. I didn’t add the reason why that is important. We’ll be doing a lot of travelling, hiking and jungle trekking so we have to haul everything including our 2 year old.

Some comments are on the more conservative side and others made a more nuanced statement. I’m inclined to conclude that in the end it is possible and wouldn’t matter too much. It could be that the NDL limit is reached a bit faster in theory but in practice there will be a bunch of other divers so on average it will be more or less the same. The liveaboard comparison is a good example.

Would that be the right conclusion or am I reaching?

 

[JMarc]

Your concerns about the weight of an spg is very odd, unless you've got muscular dystrophy

Divers concerned about weight while traveling are usually concerned about airlines limits on luggage, not about their capacity to carry them.

 

[Khoujo1]

As a non-dive professional, your plan strikes me as unduly risky. Diving is a sport that benefits from redundancy. Many divers have a primary and backup computer on each dive. Many divers that use AI have an SPG for backup (our favorite guide in Hawaii recently told us she would never go down with just an AI to rely on).

I understand trying to trim weight, but surely there is something you don’t need to bring that weighs the same as the SPG.

I would listen to previous responses from actual dive professionals and those who have traveled to Komodo. Bring both computers and the SPG.

 

[johndiver999]

As a practical matter, for recreational type diving, the computer doesn't care much at all about prior dives that were 18 hours ago. However, using a computer in this manner (every other day) will inject some small degree of conservatism in the displayed results.

I think I would bring another computer however. What if one diver violates the computer (for some reason) - it might lock up for a day and then the next diver scheduled to use the computer has an issue and might not have access to a working computer.

 

[lexvil]

While the overall plan seems nuts (all that hiking stuff) and may I offer perhaps a simpler idea, leave the Suunto and pod at home and bring the AL 330 and the SPG and pick up a second simple wrist type computer.