Am I the only one that dives with 2 computers?

[RJP]

I'm willing to bet that the OP with the Luna and the Zoop will have to be most careful with making sure the Zoop isn't violated. Now, you dive the Luna as your primary and it says you have 35 mins NDL but the Zoop only says 28 mins. Zoop will likely lock you out .

Hang the zoop on the line when you get out of the water. Or do an extra seven minutes on your safety stop... that's when the leprechaun riding a while shark is going to come by anyway.



But seriously... where are you getting the 35min vs 28min NDL example?

People love to beat up on how ultra conservative the Suunto algoritgm is. My buddy dives an Oceanic, I dive a Suunto. So effectively, he is diving a Suunto as his backup. We probably have somewhere on the order of 300 dives together.

My Suunto has never - NEVER EVER - limited our dive time on a recreational dive or caused us to need to leave the water earlier than his computer. On a recent dive in Bonaire to the Windjammer (+200ft) my Suunto gave me ONE extra minute of deco on a dive with 89 minutes of total run time. (And I hit 210ft while he only hit 198ft.) So if you want to consider that to be overly conservative... so be it. Personally I can't imagine a dive profile where my Suunto is going to give me 7 minutes less bottom time than my buddy's Oceanic.

 

[tstormdiver]

I dive 2 Petrels at all times, with no worries.

 

[DogDiver]

For Roatan 4 dives a day 6 days in a row. I keep an older DiveRite in my BC pocket. Never had to use it yet, but the inconvenience of loosing an afternoon of diving in case of a primary failure is peace of mind.
For all you table guys out there. I also carry a NAUI Ean 32 table in my BC pocket. Along with my primary Uwatec Tec2G I have my trusty Citizen pro master dive watch bottom timer. [emoji41]


Sent from my iPhone using Tapatalk

 

[RJP]

Could I survive without a computer that has a record of my ridicule load? Most likely, but why should I.

What model is that? I usually need to manually track the amount of ridicule I get during a dive trip.

 

[Jim Lapenta]

Shearwater Predator and OMS bottom timer or Oceanic Veo as back up for recreational. In my wet notes are the Navy tables. I also have a written plan, even for recreational dives, figured on v planner. So if the Predator would die I'd switch to the Veo or go to tables cut on v planner with a bottom timer. No need to sit out for 24 hours or even 12 hours if I actually did what every diver is supposed to do and plan the dive and follow the plan.


Where one could get into trouble is if they allowed someone else to do all the work of planning and conducting the dive, then blindly followed that person like a sheep to slaughter. Even with a computer that's working, too many people seem to think between that and a guide or DM they can abdicate all responsibility for themselves.

That's where you get the ridiculous statements about being out for 24 hours after a couple recreational dives. When you don't train divers to be divers you can get away with that kind of nonsense.

 

[Dirty-Dog]

What model is that? I usually need to manually track the amount of ridicule I get during a dive trip.

Is that measured in RPM (Ridicules Per Minute)?


Sent from an old fashioned 300 baud acoustic modem by whistling into the handset. Not TapaTalk. Really.

 

[EFX]

Ridiculous...Figure a square profile, pad the surface interval, and run it on tables with the appropriate group. Amazing that this stuff has been forgotten, hilarious even.Geez, you guys realize we used to dive WITHOUT computers at all right? You're telling me you can't go backward because the computer fails in the middle of a dive instead of starting a dive without one? Wow.

Get your max depth from your buddy, known depth of the sight or from the sonar on the boat, you know how long you went down for, boat captains and mates are tracking this, as well as your dive buddy. Depth and time, that's all you need. Geesh.

Actually, you don't need to know the actual depth at all. What you will need is a timer or stop watch and your buddy's computer. Assuming you stayed reasonably close to your buddy during the last dive and came up together have him go into into planning mode on his computer. Get the SI time from your buddy and start your timer. You will need to track ongoing SI. Have him go to 60 ft and give you the max BT for that dive. This doesn't have to be your actual depth for the next dive. Go to the repetitive dive table for 60 ft and find the max BT (on PADI's table this is the bottom number). Read up to the surface interval credit table and find the SI your buddy gave you. Read across to the NDL table. The group designation between the NDL and SIT is your group at the end of the last dive. Now, plan the next dive. If you plan to descend in x total minutes of SI, subtract the SI your buddy gave you from this total. The result will be the remaining time of SI as shown by your timer. To find your starting group for the next dive (at the end of your SI) start at the NDL table at the previously calculated group and read across to the SIT to the time of the total SI. Read down to the bottom to get your new group designation. It sounds complicated but if you follow it on actual tables it's easier to understand.

 

[tbone1004]

Ray, numbers were pulled out of thin air as an example. It is unlikely that they will be significantly far off, but the difference is really what you think of as a backup, which implies it has the same functionality as the primary allowing you to continue uninterrupted, or a spare where you end up having to dive differently whether significant or not, because they function differently.

 

[RJP]

Ray, numbers were pulled out of thin air as an example. It is unlikely that they will be significantly far off, but the difference is really what you think of as a backup, which implies it has the same functionality as the primary allowing you to continue uninterrupted, or a spare where you end up having to dive differently whether significant or not, because they function differently.

Not nitpicking the numbers per se, but using an "out of thin air" example that may well be 500-700% off from reality doesn't help anyone. In the real world you might see a one minute difference on a recreational dive with a run time of 35min.

Sure, while theoretically it would make the most sense to buy computers with the same/similar algorithm... the practical implications of a recreational diver using a backup computer with a "more conservative" algorithm are effectively meaningless. Someone who already owns a Suunto would be perfectly happy with an Oceanic BUD as a backup... or buying any manner of new primary and relegating the Suunto to backup status. There'd be no reason for that person to buy TWO new computers in order to have the same algorithm.

 

[Superlyte27]

Actually, you don't need to know the actual depth at all. What you will need is a timer or stop watch and your buddy's computer. Assuming you stayed reasonably close to your buddy during the last dive and came up together have him go into into planning mode on his computer. Get the SI time from your buddy and start your timer. You will need to track ongoing SI. Have him go to 60 ft and give you the max BT for that dive. This doesn't have to be your actual depth for the next dive. Go to the repetitive dive table for 60 ft and find the max BT (on PADI's table this is the bottom number). Read up to the surface interval credit table and find the SI your buddy gave you. Read across to the NDL table. The group designation between the NDL and SIT is your group at the end of the last dive. Now, plan the next dive. If you plan to descend in x total minutes of SI, subtract the SI your buddy gave you from this total. The result will be the remaining time of SI as shown by your timer. To find your starting group for the next dive (at the end of your SI) start at the NDL table at the previously calculated group and read across to the SIT to the time of the total SI. Read down to the bottom to get your new group designation. It sounds complicated but if you follow it on actual tables it's easier to understand.

My way is safer.

Buddies never seem to stay close enough (in open water anyway) that I'd rely on their computer for profile. How many times have you or your buddy been 20' above you looking down at you and your task? However, the bottom is the bottom.