Sports Divers and Limited Decompression

[AndyMCrowe]

Hello

In the definition of a Sports Diver it says that they are qualified to do limited decompression dives. However I'm having trouble finding a definition of the limits on limited decompression. The only reference I've come across is from rebreather notes saying a maximum of 10 minutes and 6 metres. Does this hold for Sports Divers too?

This may also vary from club to club and I was wondering what (if any) limits on decompression diving clubs tend to put onto their sports divers.

Many Thanks

Andrew

[Matt-75]

No idea what the official limits are.

I did 1@9m and 7@6m after an unhappy moment last year, and several 3@6m from just general dives where ive come up through a cave at a normal ascent rate but with a steeper ascent angle. Out of those, only one was planned. :(

Its not a recommended way of diving for good reason, but deco happens. Its better if you add it in to your plan as a contingency or backup plan, maybe as an egress route should something go wrong, then at least if it does go pear you can just swap to an alternate plan to get you out asap. Not planning for the unexpected is a good way to get hurt.

[Nick Argue]

Hello

In the definition of a Sports Diver it says that they are qualified to do limited decompression dives. However I'm having trouble finding a definition of the limits on limited decompression. The only reference I've come across is from rebreather notes saying a maximum of 10 minutes and 6 metres. Does this hold for Sports Divers too?

This may also vary from club to club and I was wondering what (if any) limits on decompression diving clubs tend to put onto their sports divers.

Many Thanks

Andrew

Where did you see this? In my copy of the Instructor manual under the SD definition it just says "plan and conduct dives requiring mandatory decompression stops"

[MattS]

I remember this from the old Club Diver / Sport Diver syllabus. I thought it had been dropped beacause it encourages SDs to use the most aggressive profile they can come up with.

[AndyMCrowe]

On the BSAC website:

http://www.bsac.org/page/276/sports-diver.htm

To add to my previous post, in the club I did most of my training in there was an attitude to err on the side of caution and not to have sports divers routinely do decompression diving. Mainly it was viewed as required knowledge and ability so that the appropriate just deeper/longer/worst case scenarios can be planned and performed. Most people didn't consider planning to do deco as part of the normal dive plan until they were dive leaders. The club I joined recently are a little more relaxed about decompression dives, so i was wondering how other clubs deal with this.

Andrew

[Nick Argue]

On the BSAC website:

http://www.bsac.org/page/276/sports-diver.htm

To add to my previous post, in the club I did most of my training in there was an attitude to err on the side of caution and not to have sports divers routinely do decompression diving. Mainly it was viewed as required knowledge and ability so that the appropriate just deeper/longer/worst case scenarios can be planned and performed. Most people didn't consider planning to do deco as part of the normal dive plan until they were dive leaders. The club I joined recently are a little more relaxed about decompression dives, so i was wondering how other clubs deal with this.

Andrew
Ah in the top paragraph, the rest is as per the manual. No idea what limited means in this context. Mind you I would describe myself as someone who does limited deco, normally no more that 15min, which is my boredom limit more that anything else.

Nick

Nick

[Hamish]

Andy wrote
In the definition of a Sports Diver it says that they are qualified to do limited decompression dives. However I'm having trouble finding a definition of the limits on limited decompression.

Andy,

I'm not sure so is best to get it from the horses mouth so to speak, but I suspect that it referes to keeping to depths/times and decompression stops as laid down in the BSAC 88 tables up a maximum depth of 35m.

Otherwise a SD could use his computer and step outside the limits as laid down by the 88 tables.


Hamish

[Luke K]

Hello

In the definition of a Sports Diver it says that they are qualified to do limited decompression dives. However I'm having trouble finding a definition of the limits on limited decompression.

Is the Sport Diver Lecture ST4, The slide before the summary states the following

"Advisable to limit decompression stops to a total of 20mins within a 24hr period"

I hope this helps.

[Paul Morris]

Is the Sport Diver Lecture ST4, The slide before the summary states the following

"Advisable to limit decompression stops to a total of 20mins within a 24hr period"


Yes, I'd always interpreted this as "limited" to the planning of BSAC tables. i.e. 20/21 mins decompression (the edge of the tables).

Remember these are PLANNED deco dives. Most dive computers do not allow you to plan deco dives, so this is what they should be using for indicative planning (until they actually do the dive and find their Buhlmann computer want's far more :D but thats another story).

Anything more than this requires you to use something other than BSAC 88s' for planning, and that will be taught in the Extended Range course. A sensible course for anyone regularly doing 15min+ deco. (when you then find out the "quickest" tables for accelerated decompression were in fact the 88s' :eek: )

[MattS]

Yes, I'd always interpreted this as "limited" to the planning of BSAC tables. i.e. 20/21 mins decompression (the edge of the tables).The 20m advisary is from Page 4 of the 88s. It does not necessarily mean you are diving at the edge of the tables. 34mins @ 33m, 2Hr SI, 31mins @ 21m, is not on the edge of the table. That used to be a fairly typical day for me.

Remember these are PLANNED deco dives. Most dive computers do not allow you to plan deco dives, so this is what they should be using for indicative planning (until they actually do the dive and find their Buhlmann computer want's far more :D but thats another story).Do not agree. You 'should' use the same table for planning decompression as you do for decompression diving. We seem to agree on the why of it.

I do not recall anything in BSAC materials that indicates an SD can not use a dive computer for decompression diving. Many do indeed allow decompression to be planned. Alternatively the Buhlmann tables can be easily downloaded or purchased. And of course there are Buhlmann PC, PDA and mobile phone based decompression applications available. The algorithm in a dive computer may not exactly match Buhlmann, but it will be close enough for planning purposes...unlike BSAC 88s.

Anything more than this requires you to use something other than BSAC 88s' for planning, and that will be taught in the Extended Range course. A sensible course for anyone regularly doing 15min+ deco.For SDs that are racking up 15mins+ of air decompression the Advanced Nitrox course would seem a sensible route. 15mins+ of Nitrox 88s decompression in the Sport Diver depth range accounts for some pretty serious bottom times. ERD comes into play when bottom depth increases, Oxygen content decreases and stop times are otherwise unavoidable. For Sport Divers the safest option has to be not to take on the Nitrogen in the first place.

Personally I went a different ERD route - the BSAC courses had only just launched at the time. So I had to learn Buhlmann tables and ERD. I would say it is sensible knowledge for anyone involved in ERD to accquire. PC based dive planning tools (as used during BSAC ERD training) are well and good but you can't use them underwater ;)

when you then find out the "quickest" tables for accelerated decompression were in fact the 88s' :eek: )Well the 88s did not bend me...but I no longer fall asleep with a screaming headache on the way home ;)

[MattS]

The club I joined recently are a little more relaxed about decompression dives, so i was wondering how other clubs deal with this.Get them Nitrox trained as soon as possible. Preferably before qualifying as SD. Once they qualify as SDs I prefer the first steps into decompression to be carried out using Nitrox following an air schedule. When they have a bit of experience we can start thinking about real decompression ceilings, Advanced Nitrox and gas switching to 50% for safety.