Diving Doubles

[jonnythan]

Doubles allow me as a non-deco diver to do two deepish (100 foot) dives to the NDL without having to switch tanks or leave 15-20 cf on the surface in the "mostly empty" tank.

More efficient use of gas, more redundancy, etc etc.

 

[HybridDiver]

so the only longer way to get longer time under the water is enriched air knowen as nitrox right? yes yes im new to the advance stuff but OW i know well.. cause i want to start diving doubles this summer i want to get into the trimix tech diving stuff one day 2 heehee i want to go deep

 

[jonnythan]

so the only longer way to get longer time under the water is enriched air knowen as nitrox right? yes yes im new to the advance stuff but OW i know well.. cause i want to start diving doubles this summer i want to get into the trimix tech diving stuff one day 2 heehee i want to go deep

The only way to get more bottom time without going into deco, yes.

But don't rush into anything. Most of the interesting stuff is relatively shallow

 

[DiverBuoy]

Decompression isnt something to be scared of. Despite some agencies trying to scare people off contrary to what they want people to think it isnt that difficult, isnt that dangerous and you dont die on entering decompression. At its basic level anyone capable of buoyancy control is capable of a decompression dive with the right equipment.

It is a choice however, to cross over to a scenario where direct ascent to the surface is not longer possible with out more serious consequences ... which is why it is not a choice for everyone. That said, decompression diving is enjoyed by many people and while you may get bored listening to the same old mp3 songs hanging on a deco line for an hour, it will afford you access to more places and for longer periods - so it definitely has a certain appeal.

 

[Henryville]

Using Nitrox 36 you could do 100ft for 35min with only 2 minutes of deco at 10ft

Like this.

Dec to 100ft (2) on Nitrox 36.0,
Level 100ft 33:00 (35) on Nitrox 36.0
Asc to 10ft (38) on Nitrox 36.0,
Stop at 10ft 2:00 (40) on Nitrox 36.0
Asc to sfc. (40) on Nitrox 36.0

Anything longer and it would be best to take an higher % nitrox for deco gas.

Or, if you wanted to use air, using VPlanner (decompression software - make sure you have proper training) I get about 40 minutes of deco on air with a conservatism rating of +2. At a conservative SAC rate, I'd use about 150CF of gas to do the dive. I wouldn't want to use double 80s for that (cutting it a bit too close for my taste,) but I might in 95s or larger tanks.

In other words, as others have said, with proper training 40 minutes at 100 is quite doable in doubles even without carrying high FO2 gas for an accelerated deco.

You will want to get some more experience before seeking the training you will need to do something like this safely.

 

[HybridDiver]

heehee thats what im talking about i dont want to see fish i just want to go deep i dunno its my type of rush i see fish all the time i work at a marina. my rush is going deep thats i want to get into deco diving i just want to start with normal gas to get used to it thats why i was asking how deep can i go and for how long type of thing.

 

[Don Burke]

heehee thats what im talking about i dont want to see fish i just want to go deep i dunno its my type of rush i see fish all the time i work at a marina. my rush is going deep thats i want to get into deco diving i just want to start with normal gas to get used to it thats why i was asking how deep can i go and for how long type of thing.

In my opinion, that is backwards.

A Nitrox certification will let you dive for longer periods with no mandatory decompression stops.

Once you have worked out the details of longer dives, you can get into dives requiring stops.

 

[HybridDiver]

oh ok my bad my bad. see im learning before ima start deco diving i want to get into i downloaded V-planner to mess around with lol ima take it lil bit at a time

 

[Don Burke]

All dives are decompression dives, it's only a question of whether your decompression is made above or below the water

Actually, all dives involve decompression above and below the water.

The question is whether the ascent needs to be modified to slow offgassing.

 

[HybridDiver]

k lets say ima do a dive to 100 feet with doubles ima stay for about 40 mins when its time to go up ima stop at 80 for a min then 60 for a min then 45 for 50 secs then 25 for 50 secs then ima sit at 15 for couple mins then surface depending on air? type of thing?