Recommend me a deco course.

[kaerius]

So I've got somewhere over 400 dives now, and on my last dive trip I went deco accidentally for the first two times. I just ended up having to trust my computer.

I'd really like some better training to deal with deco, both for future accidental deco, and for planned deco. I don't have much interest so far in going to tech depths, or carrying 80kg worth of tanks, but a good grounding in deco theory would be nice. I'm a padi instructor, and I know about tec-rec, but I figure I'd open up for any agency.

 

[KD8NPB]

Check out Mark Powell's "Deco for Divers" for a good book on "intro to deco theory".

Unfortunately, the 80 kg worth of tanks a necessity for safety's sake.

After reading Deco for Diver's, I've made a habit of carrying an AL40 of an oxygen rich mix on deeper dives. I perform the safety stop on this mix to accelerate N2 offgassing, in case I pushed into my safety margin too much.

 

[TSandM]

You might consider contacting Richard Lundgren, who is a GUE instructor in Sweden. He is a really nice man, and he teaches both Fundamentals (GUE's entry level class) and Tech 1, which would be your first step into decompression diving. Both classes would be instructive and probably help polish your skills, as well.

 

[boulderjohn]

I wrote a Distinctive Specialty that has a section on what you describe. If you send me your email in a PM, I will send you the chapter. It is by not remotely as complete as Powell's book, but it may tell you enough to get you started at least.

 

[kaerius]

Unfortunately, the 80 kg worth of tanks a necessity for safety's sake.

Note again that I'm still sticking to rec depths(max 40 meter) for now. It was a bit tongue in cheek, but I'm not going to be running into any multi-hour deco obligations anytime soon. More interested in "how do I plan this to incur less than half an hour deco" situations. In the two dives so far where I've ended up deco, my longest obligation(according to my suunto vyper) was 13 minutes.

Thanks for the recommendations everyone.

 

[DevonDiver]

kaerius - the requirement for gas redundancy isn't variable with 'severity of deco'.

If you conduct planned decompression you lose access to the surface. That means you have to deal with any/all foreseeable problems at depth. That means (1) effective redundancy and (2) using at least rule of thirds gas management. Those two factors necessitate 2x tanks, at least.

Tech/deco isn't for everyone. If not prepared to make the commitment in effort, time and expense, then simply avoid exceeding NDLs... no problem.

 

[Dive-aholic]

More interested in "how do I plan this to incur less than half an hour deco" situations. In the two dives so far where I've ended up deco, my longest obligation(according to my suunto vyper) was 13 minutes.

Thanks for the recommendations everyone.

How about planning your dives to not incur any decompression obligation. Suunto dive computers are notoriously very conservative and it could be that you did plan those dives without any deco but your Suunto put you in deco anyway. If that's the case it may be time to get a new dive computer. If that's not the case and you didn't plan your dive and found yourself in deco then that is a result of poor planning. Time to start planning your dives so this doesn't happen.

 

[PfcAJ]

Note again that I'm still sticking to rec depths(max 40 meter) for now. It was a bit tongue in cheek, but I'm not going to be running into any multi-hour deco obligations anytime soon. More interested in "how do I plan this to incur less than half an hour deco" situations. In the two dives so far where I've ended up deco, my longest obligation(according to my suunto vyper) was 13 minutes.

Thanks for the recommendations everyone.

Are you posting to tell us you already know how to do these dives or to ask how to do/learn to do them? Your first post seemed to suggest that you wanted to learn something, and this post you sound like you've got it all figured out. A 30min deco obligation is a 3 tank deal.

This stuff isn't a game, and you can get hurt really bad if you mess up. Take the advice from the people who have been there/ done that. When they make suggestions, they're doing it for a reason.

 

[kaerius]

Sorry if I came off wrong.

I understand the redundancy requirement. When I spoke of 80kg, I was envisioning a deep dive 6 tank rig. Baby steps, make my way up to two tanks first, at recreational depths. Heck I had no idea 30 minutes deco was a 3 tank deal, I was figuring 2, I guess it's the rule of thirds? There's a reason I'm seeking training... I simply don't know much on the subject.

Dive-aholic: I was descending to see what my buddy who was significantly deeper was looking at, noticed I ended up with 1 minute no deco time, and while ascending back to shallower depth I tripped over to deco, oops. Similar story for the other accidental deco, though that time I was following a divemaster until my NDL was too short, tripped deco while ascending.

Suunto being too conservative. Maybe, though my buddy's poseidon computer was even more conservative, so much so that she was resigned about it, computer ordered deco stops were the new norm for her. Seriously, first dive of the day, if we dove the same profile, and I was well within NDL, her computer was usually showing deco. She said it was one of the least conservative when diving nitrox though, usually giving her more time than anyone else.

 

[PfcAJ]

The two tanks on your back are enough for you on the bottom and hold the reserve to get you and your dive buddy to your deco gas. For the bottom times and depths you're talking about, a single tank just isn't enough volume, not to mention is provides no redundancy at all.

The 3rd tank is a deco bottle. It behooves you to use one as is reduces your deco time and reduces the amount of gas you need to carry on your back. An al40 is a good starter tank and works well for 50% or 100% o2 with deco times up about 30mins.

As Lynne mentioned, get into a GUE Fundamentals class ASAP. Even if you decide to take another training route later on, it will give you a solid foundation and get you started in the right direction. You've got a great GUE cadre in Sweden, too. After Fundamentals, Rec 3 or Tech 1 will become options that could fulfill your needs, and those options are best discussed with an instructor.