What should I do?

[ScubaSteve]

......The 3 minute safety stop is strongly recommended but optional whereas a 3 minute deco (decompression) stop is mandatory and only used for technical diving and when recreational divers exceed recreational limits during a dive.......

Just for clarification because a lot of new divers posts and read this section, this statement is not entirely true. Any diver can go into a mandatory decompression stop situation any time they deplete their NDL time. This absolutely does not require exceeding any recreational depth limits. It is a matter of residual notrogen loading at the start of the dive (if applicable) and the accumulated nitrogen from the current dive. A diver could do many dives over many days, but unless their body was able to eliminate all the nitrgen from the previous day's adventures, then it just compounds and gets added. This is why when doing tables, we have an end of dive group and a start of "subsequent dive" group (based on the length of the surface interval).

 

[Tigerman]

Just for clarification because a lot of new divers posts and read this section, this statement is not entirely true. Any diver can go into a mandatory decompression stop situation any time they deplete their NDL time. This absolutely does not require exceeding any recreational depth limits. It is a matter of residual notrogen loading at the start of the dive and the accumulated nitrogen from the current dive. A diver could do many dives over many days, but unless their body was able to eliminate all the nitrgen from the previous day's adventures, then it just compounds and gets added. This is why when doing tables, we have an end of dive group and a start of "subsequent dive" group (based on the length of the surface interval).

Also emergency deco is not 3 minutes (atleast according to PADI) but minimum 8 minutes at 15 ft if you are less than 5 minutes into deco obligations and minimum 15 minutes if youre more than 5 minutes into deco obligation..

 

[jupitermermaid]

Tom, you've gotten some great advice from everyone. Is this a new buddy you're diving with or someone you know (hence, know that (s)he is prone to push the limits of your plan? I've dove with both types. The first one knew she got narced easily, so we made a plan that if she felt she was getting looney then she would hold my hand and we would ascend about 10' or so at a time till she got her bearings back (which we ended up doing and had a fantastic dive together). The other one decided she liked doing her own thing and didn't care about "plans", so I stuck to the original plan and stayed close by other divers while she played and got bent. I still dive with the first diver whenever she comes down this way; the second diver I will not dive with again. If you chose to dive with this buddy and aren't sure which way he'll go, why don't you invite another person or two along with you so you don't end up solo in the worst case scenerio? Just a thought. In any case, your safety comes first.

 

[4sak3n]

I once went into deco by mistake and incurred an 11min deco stop with an instabuddy - however we'd discussed hand signals so I was able to ask him to stay with me, so it is a good idea to go over hand signs for things like deco stops, and safety stops.

Just out of interest could you tell us this story in detail? Were you using a computer or diving by tables? Was that a precisely calculated 11 min of deco or did you just exceed your NDL and decided to spend a good amount of time and padded your deco stop to be safe?

I ask because 11 mins of deco is a LOT to get into accidentally. Its not a matter of spending 1 or 2 mins extra at 30m ... it is a lot longer than that.

That and diving stories are fun so any excuse to hear one is a good excuse!

P.S. Sorry for the hijack.

 

[Sas]

Just out of interest could you tell us this story in detail? Were you using a computer or diving by tables? Was that a precisely calculated 11 min of deco or did you just exceed your NDL and decided to spend a good amount of time and padded your deco stop to be safe?

I ask because 11 mins of deco is a LOT to get into accidentally. Its not a matter of spending 1 or 2 mins extra at 30m ... it is a lot longer than that.

That and diving stories are fun so any excuse to hear one is a good excuse!

P.S. Sorry for the hijack.

Sure no hassle.

I calculated my maximum bottom time off dive tables (SSI, if that makes a difference): at 24m/79ft (max depth of the dive) I would have 30 minutes. I was diving with air.

I did not realise, however, that my Smartcom computer when set to Level 0 (the least conservative actually) only gives me 27 minutes at 24m/79ft.

Anyway, I reached a max depth of 24.2m/79.4ft and I stayed at that depth (pretty much 24m/79ft the whole time, was a square profile) for 29 minutes. It showed me a deco time of 7 minutes at this stage, which increased to a deco stop of 11 minutes at 3m once I hit 15m/49ft, the dive time had reached 31 minutes. Overall the dive time was 49 minutes so I did more than 11 minutes actually. Whilst I knew I had followed what the tables said, I thought I better follow the most conservative route and do what my computer said. My buddy said his computer showed no deco incurred (but it did show a 3 minute safety stop, which is the default) but he was happy to do the stop with me. I should have really been watching my computer more closely but because I knew what the tables said, I never checked the NDL time, only the dive time.

I do not think that 11 minutes of deco is a long time to incur actually? From my dive tables and what I learned in my OW course: "Should you exceed the Doppler No-Decompression Time Limits by less than 5 minutes on any dive, it is recommended that you ascend normally to 5m and stop for at least 10 minutes or longer if your air supply allows".

Hope that helps

 

[NadMat]

I am diving with my buddy and we plan to hit about 100.. play abit and gradually cruise up to 60 then 30 with a stop at 15. Well at 100 it drops quick and get cold and dark. What am I supposed to do if he startes to flirt to 120....130 and just starts to ignore me and my signals.

I've also been in the position where my instabuddy decided it was time to head to the surface and my 3 min deco wan't finished,or even properly started.

for the first I would have grabbed him before 110 and shown them their depth and come up to agreed upon depth, or even shallower if they seem narced.

for the second instance, if it was 'deco' I would definitely finish my deco, if it was just a safety stop I would probably still finish it unless my buddy seemed to be in some distress that might need my attention.

I am there to help my buddy prevent/recover from minor 'oops'. I will do so to whatever extent possible without making myself a victim. If my buddy has willfully violated the plan and my attempt to correct them then I will finish my dive solo since they have decided to dive without me.

JMHO,YMMV.

 

[ScubaSteve]

Sure no hassle.

I calculated my maximum bottom time off dive tables (SSI, if that makes a difference): at 24m/79ft (max depth of the dive) I would have 30 minutes. I was diving with air.

I did not realise, however, that my Smartcom computer when set to Level 0 (the least conservative actually) only gives me 27 minutes at 24m/79ft.

Anyway, I reached a max depth of 24.2m/79.4ft and I stayed at that depth (pretty much 24m/79ft the whole time, was a square profile) for 29 minutes. It showed me a deco time of 7 minutes at this stage, which increased to a deco stop of 11 minutes at 3m once I hit 15m/49ft. Whilst I knew I had followed what the tables said, I thought I better follow the most conservative route and do what my computer said. My buddy said his computer showed no deco incurred but he was happy to do the stop with me. I should have really been watching my computer more closely but because I knew what the tables said, I never checked the NDL limit, only the dive time.

I do not think that 11 minutes of deco is a long time to incur actually? From my dive tables and what I learned in my OW course: "Should you exceed the Doppler No-Decompression Time Limits by less than 5 minutes on any dive, it is recommended that you ascend normally to 5m and stop for at least 10 minutes or longer if your air supply allows".

Hope that helps

The one and only time I have exceeded my NDL (by seconds I might add because I looked down at my computer and watched it flip from 1 minute remaining to "Go to ceiling of 10 feet for 10 minutes". I dive a Suunto Cobra and was apparently not quite as religious at checking my guages (definitely my bad) but will never not follow it if it tells me to stop for some reason unless it is an emergency. Extra stop time (as long as air is sufficient for the situation and possibly problems) is never a bad thing.

 

[4sak3n]

Thanks for sharing! :bounce2:

It sounds like your computer is very conservative. I have exceeded an NDL by two mins once or twice dunce on my Vytec and my deco obligation has either cleared before I reach 3m or I only have 4 or 5 mins left.

To give you an idea, I simulated a dive to 24m on my Vytec and had to go 7 minutes beyond the NDL before I got 11 mins of deco.

 

[Sas]

Thanks for sharing! :bounce2:

It sounds like your computer is very conservative. I have exceeded an NDL by two mins once or twice dunce on my Vytec and my deco obligation has either cleared before I reach 3m or I only have 4 or 5 mins left.

To give you an idea, I simulated a dive to 24m on my Vytec and had to go 7 minutes beyond the NDL before I got 11 mins of deco.

Yes I believe it is conservative, a number of people have told me this. It has levels from 0 to 5, at L5 it gives 4 minutes at 24m to give you a comparison. To be honest, when I bought it, I was pretty new to diving, it was second hand and cheap so I never gave a thought to how computers vary in their conservatism. So quite pleased I got a conservative one!

 

[diver 85]

I am diving with my buddy and we plan to hit about 100.. play abit and gradually cruise up to 60 then 30 with a stop at 15. Well at 100 it drops quick and get cold and dark. What am I supposed to do if he startes to flirt to 120....130 and just starts to ignore me and my signals.

I've also been in the position where my instabuddy decided it was time to head to the surface and my 3 min deco wan't finished,or even properly started.

In reality that's why every diver should be prepared for a 'solo dive' of some sort @ any time----no one promised you this human being you're diving with will make it for the whole dive, many things could make your dive plan go out the window......Just remember the very ultimate part of every dive plan is for you to make it back home that day safe and sound, your buddy may or may not, depending on his sanity--- ie some people are just plain stupid(sounds like you've had your fair share of the latter).........better luck in the future......