Where to go from here? [Archive] - BSAC Scuba Diving Forums

TerryH

03-01-2005, 17:38

Ok we've discussed this before, but we now have an awful lot
of divers who are in this dilemma.

We are a club with a bunch of Dive Leader/Advanced divers
who average 50-70 UK dives each per annum. The vast majority of
these are quality UK extended dives in the 35-45m range with
limited deco (usually around 15min max) and we are looking at
dive times about 60 min+. Most of us use twins of
various configerations and some also use stages. As a VERY
stringent training/diving club we train doing shutdowns,
mid-water deploy etc. at almost every opportunity. This also
includes workup dives (a gaggle of our mob have been at Vobster
playing with twins over the last two days).

The club's divers are automaticly taught BSAC Advanced Nitrox
as soon as they finish Sport, so all the above will be at this
level.
So we have a bunch of pretty reasonable DL/Adv who are ok to
50m + deco and can use upto 50% Nx.

So we can ...

Pay a shedload of dosh to do BSAC ERD and get 80% + accelerated
deco and nothing new that we dont already do.

or

Get a knockdown TDI Adv Nx (already have BSAC Adv) and get
100% and accelerated deco.

The badge is irrelevant, what it allows you to do is more
important, the question is "where to go from here?"

TerryH

iainmsmith

03-01-2005, 18:15

So we have a bunch of pretty reasonable DL/Adv who are ok to
50m + deco and can use upto 50% Nx.

So we can ...

Pay a shedload of dosh to do BSAC ERD and get 80% +
accelerated deco and nothing new that we dont already do.

or

Get a knockdown TDI Adv Nx (already have BSAC Adv) and get
100% and accelerated deco.

The badge is irrelevant, what it allows you to do is more
important, the question is "where to go from here?"

For the diving you are already doing, IMO, where you ought to be going is towards trimix. Hence any course you do should be a step in that direction.

As I'm sure you're not going to accept a recommendation to go down the GUE Fundamentals/Tech 1 path, I would suggest finding out whether BSAC ERD or TDI ANX is accepted for entry to any trimix courses. I have a feeling that the latter is, but the former is not, but am not certain about this.

If it simply comes down to 80% vs 100%, I would suggest going for the TDI course, purely because it gives you the flexibility to use O2 if you choose. Equally, if you choose to stick with 80%, you can do so.

However, I wouldn't necessarily expect that either qualification will allow you to do a great deal that you can't already do with your existing tickets, other than access to high FO2 gases. What you will find is that if your current diving is planned on BSAC '88/Nitrox tables or done by following wrist computers, so-called "accelerated" deco is likely to be longer than your current deco. Unless you have expensive multi-gas dive computers, accelerated dives get planned on software and are "accelerated" compared to the back-gas profiles generated by the same software. These are pretty much universally more conservative than '88s/Nitrox or wrist computers.

Hence you may even be able to justify doing "accelerated" dives within the limits of your existing qualifications, as the resulting profiles are likely to be more conservative than what you could do on the tables!

Whichever course you go for, the key thing is the instructor. To establish a foundation for advanced diving (and, IMO, even for this level) you need someone who is prepared to take you, your knowledge and your skills to pieces in a constructive fashion!

Or you could just wait for the BSAC Trimix course to come along.

Iain

janos

03-01-2005, 18:34

The badge is irrelevant, what it allows you to do is more
important, the question is "where to go from here?"

Not an expert on this at all, but why not have a chat with a 'technical' instructor you trust. Half a dozen of us in my club are going to do ERD / trimix (some doing each course - the trimix is an extra day) with Jack Ingle later this year. Personally I'm not (yet) interested in huge depths, but believe that the additional skills will make my diving in the 30m / 40m range safer, especially for longer durations.

As you say, the badges aren't really important, so if there's a lot of you why not talk to someone and see if they can tailor something to your needs.

Laters,
Janos

TerryH

03-01-2005, 19:33

For the diving you are already doing, IMO, where you ought to be going is towards trimix. Hence any course you do should be a step in that direction.

As I'm sure you're not going to accept a recommendation to go down the GUE Fundamentals/Tech 1 path, I would suggest finding out whether BSAC ERD or TDI ANX is accepted for entry to any trimix courses. I have a feeling that the latter is, but the former is not, but am not certain about this.

If it simply comes down to 80% vs 100%, I would suggest going for the TDI course, purely because it gives you the flexibility to use O2 if you choose. Equally, if you choose to stick with 80%, you can do so.

However, I wouldn't necessarily expect that either qualification will allow you to do a great deal that you can't already do with your existing tickets, other than access to high FO2 gases. What you will find is that if your current diving is planned on BSAC '88/Nitrox tables or done by following wrist computers, so-called "accelerated" deco is likely to be longer than your current deco. Unless you have expensive multi-gas dive computers, accelerated dives get planned on software and are "accelerated" compared to the back-gas profiles generated by the same software. These are pretty much universally more conservative than '88s/Nitrox or wrist computers.

Hence you may even be able to justify doing "accelerated" dives within the limits of your existing qualifications, as the resulting profiles are likely to be more conservative than what you could do on the tables!

Whichever course you go for, the key thing is the instructor. To establish a foundation for advanced diving (and, IMO, even for this level) you need someone who is prepared to take you, your knowledge and your skills to pieces in a constructive fashion!

Or you could just wait for the BSAC Trimix course to come along.

Iain

Thanks for the response Iain, but a couple more points.
we use BSAC tables in early training and that's about it.
Trouble is that although many of us can easily cut tables etc.
There isnt a lot of point considering that every dive is
calculated via computer/same mix, even though we all know the
benefits of that actual higher percentage we use on the deco
stop.

So not really that bothered with the 80/100 argument, but
very much so with accelerated deco.

As for Tri? Well I can see one/maybe two doing it, but we are a
student club and I just cant see "group" as a whole spending
all that dosh. Seems to me and based on what's needed now,
that the awnser is a simple TDI ADV crossover.

I cant see the BSAC Tri making that much difference either as
based on the current parity with other TDI courses, it's not
likely to be any cheaper.

Sadly that inevitably will mean that these divers
will no longer bother with BSAC. That begs the question that
are we alone (I doubt it) and what (if anything) can BSAC do
to fill the gap.

TerryH

David Walker

03-01-2005, 20:13

all that dosh. Seems to me and based on what's needed now,
that the awnser is a simple TDI ADV crossover.

Not sure if you're talking about this anyway, but from the information i've got (i've been looking into doing something similar myself) then you'd be better off doing the combined TDI Advanced Nitrox & Deco Procedures - you need the Deco Procedures for the accelerated deco, and its usually only an extra ?50 or so on top of the cost of the ANx course anyway (and an extra day).

Sadly that inevitably will mean that these divers
will no longer bother with BSAC. That begs the question that
are we alone (I doubt it) and what (if anything) can BSAC do
to fill the gap.

I think BSAC do fine as a club up to Advanced Diver (excluding a few oddities, the training schemes up to there are generally very good... FCD doesn't seem to have any point to it so I missed that out) - the nitrox stuff is useful but there seems to be a growing opinion that the BSAC Nitrox stuff isn't really up to the standards of the more 'technical' agencies (which is to be expected I suppose). A friend of mine had trouble doing his rebreather course because of the 1.4ppO2 limit he had through BSAC (apparently you do the rebreather course based on your old nitrox certification, or something like that... not entirely sure how it works).

Anyway, I was looking to do something beyond BSAC AdvNitrox since I didn't think the course was all that useful - the dives were pointless (oooh, I can hold a deco stop, is that it?), most of the nitrox theory was nothing more than could be got from a bit of quick reading.
Maybe I'm just looking for something different to the average BSAC diver, but I just didn't find I got out of the nitrox course what I would have liked. Maybe a bit more about how things are done in reality (hands up who uses the BSAC tables for their dives...), or something about the types of equipment likely to be used for this type of diving (twins were actively discouraged on the regionally-run course I did).

As for trimix, I think BSAC would be better staying out of it in all honesty. The other agencies are doing a fine job of it as it is, i'd rather BSAC made sure everything else it already does is all OK before adding more new stuff. If it was going to add some new things, then something like safe (advanced) penetration techniques for wrecks (since thats what most of the dives around the UK are!). OK I would quite happily go on in and nosey around big bits of wreckage, wedging myself in small holes (oh dear...), but i'm fairly sure there's a better way to do it (ie less of the randomly swimming into holes), and apart from anything else i'd rather the people who I dive with had some kind of experience / training in it rather than just hoping for hte best (or usually not wanting to risk taking someone else in with me). As a primarily UK based club, with lots of deep and dark wrecks around our little island, something like that would be ideally suited to being a BSAC SDC surely?

David

David Walker

03-01-2005, 20:16

Not sure if you're talking about this anyway, but from the information i've got (i've been looking into doing something similar myself) then you'd be better off doing the combined TDI Advanced Nitrox & Deco Procedures - you need the Deco Procedures for the accelerated deco, and its usually only an extra ?50 or so on top of the cost of the ANx course anyway (and an extra day).

Oh, and the ANx/DecoProc combination is also entry level for the TDI trimix courses too.

David

David Bailey

03-01-2005, 21:13

I'm over in the US and as I'm planning on taking trimix classes this year I looked into BSAC equivalency. This info is direct from TDI UK and a TDI insructor over here.

TDI consider BSAC ERD to be equivalent to their Deco Procedures course. If you want to use BSAC ERD as an entry point to their more advanced courses you also need an equivalent to their Adv Nitrox (i.e. to have covered 100% O2). You can take the theory exam, but you don't have to sit through the lessons or do the dives.

With BSAC ERD and an Adv Nitrox course you can either do Entry Level Trimix or TDI ERD.

I've heard different things about the relative merits of the TDI and BSAC ERD courses. I did the BSAC version on a week-long BSAC expedition and it was excellent.

Hope this is useful
Dave

TerryH

04-01-2005, 12:31

Following on from above, has anybody got a detailed BSAC ERD
syllabus handy they can email me?

The BSAC site has a pretty weak run through and I've talked to
a few that have done it, but would like to make a more
accurate comparison with TDI etc.

Ta.

TerryH

Mark Powell

04-01-2005, 13:30

:=Seems to me and based on what's needed now,
:=that the awnser is a simple TDI ADV crossover.

Not sure if you're talking about this anyway, but from the information i've got (i've been looking into doing something similar myself) then you'd be better off doing the combined TDI Advanced Nitrox & Deco Procedures - you need the Deco Procedures for the accelerated deco, and its usually only an extra ?50 or so on top of the cost of the ANx course anyway (and an extra day).

I agree that the combined TDI Adv Nitrox and Deco procedures will give you what you want. Adv Nitrox will let you use up to 100% and Deco Procedures will cover accelerated deco.

With the situation that you describe a TDI instructor should be able to tailor something suitable for your group.

Regards

Mark Powell
TDI Instructor
Dive-Tech: Nitrox and Technical Diver Training
Tel: 07770 864327

Ben Field

04-01-2005, 13:51

> Get a knockdown TDI Adv Nx (already have BSAC Adv) and get
> 100% and accelerated deco.

This isn't a great help to you if you intend to dive within BSAC is it?

The badge is irrelevant, what it allows you to do is more
important, the question is "where to go from here?"

Well Terry, your clubs demographic doesn't sound much different from ours and this is what we have- We are a training club and we get people up to SD fairly quickly and although we don't puch them into anything "technical" we have a large % of our instructors who do deeper diving.

Generally for Adv nitrox and above you should not be considering the cost IMO, you should think about who you will be leanring from and what you might learn. Yes you can look at the web and compare straight figures like 80 or 100% max depths and whatever but if your diving is going that way it is going to end up outside BSAC remit anyway so your best off choosing your training based on what else you'll learn.

Our club includes 6 trimix and several adv nitrox divers who've done TDI courses with a local independant instructor we found. The advantage here has been that while you cover the course notes in detail you benefit from his years of experience and all the training dives are done offshore on real dives. As a by product you meet new people and form a base from which you can continue that level of diving which for alot of people needs to be outside their clubs as very few have 12 (a boat full) of equally highly qualified members.

I would stress in the strongest possible terms that you don't base your choice on outright cost alone.

And I would agree with the other replyee who asked what your end goal is- if its trimix then head in the right direction and choose an instructor you can go back to for that course.

Remember you are the customer so ask them questions like how long have they been doing it etc...

All the best,
BEN

iainmsmith

04-01-2005, 15:36

> Get a knockdown TDI Adv Nx (already have BSAC Adv) and get
> 100% and accelerated deco.

This isn't a great help to you if you intend to dive within BSAC is it?

Why not? OC divers are allowed to carry and use pure O2. See: <a href="http://www.bsac.org/techserv/o2use0304.htm" >http://www.bsac.org/techserv/o2use0304.htm</a>

Unfortunately, this change in position wasn't particularly well publicised so many haven't come across it.

Iain

matt

04-01-2005, 16:13

Hi Terry

It sounds like you are already on the edges of Extended Range Diving so an ERD/Technical course would appear a better option than taking another Advanced Nx course.

BSAC ERD is most likely the cheapest but it neglects the detail included in the tech agency courses. Specifically deco planning software is used to cut accelerated schedules, which is a pain if all you have is a set of printed Buhlmann's.

Personally I would give some consideration to IANTDs Technical Diver course. Unless it has changed in the last 6 months IANTD allow entry to their technical program based on a Nx qualification (even Basic) and requisite experience, at the discretion of the instructor. The qualification is to 54m so aligns nicely with DL and AD. Should you decide to go Trimix at a later date, you can add Normoxic or go straight to Full Trimix with IANTD or other agencies. Based on where you say you are, IMVHO this option provides you the most bang per buck.

Whether TDI Adv + Deco is a technical qualification is debateable. If you have no other Nx training it is possibly the simplest route to accelerated deco. However the qualification is to 45m so would not align with your DL/AD qualification.

HTH

Lindsey Doyle

04-01-2005, 23:21

:=> Get a knockdown TDI Adv Nx (already have BSAC Adv) and get
:=> 100% and accelerated deco.
:=
:=This isn't a great help to you if you intend to dive within BSAC is it?

Why not? OC divers are allowed to carry and use pure O2. See: <a href="http://www.bsac.org/techserv/o2use0304.htm" >http://www.bsac.org/techserv/o2use0304.htm</a>

Unfortunately, this change in position wasn't particularly well publicised so many haven't come across it.

This is dated 03/04, whereas the announcement at the last DOC that we can use 100% O2 at max pp 1.4 bar seemed to be new?

BTW, anyone know why is the BSAC ERD so expensive anyway?

tristan green

05-01-2005, 04:33

BTW, anyone know why is the BSAC ERD so expensive anyway?

From the mail shop - Course notes cost 12 pounds (and you've already got the BSAC nitrox tables, haven't you? - if not they're another 15 pounds).

What else are you paying for - the diving and the classroom time?

I did my course a couple of years ago and as I recall the cost was nominal and certainly didn't add any noticeable cost to a four day diving trip, except for the cost of the nitrox fills (hmm, maybe is was a bit more with twin 15's (28-32% 'ish) and a 7 litre stage of 80% each time).

I'd be interested to hear what other people are being asked to pay.

Cheers,
Tristan

Lindsey Doyle

05-01-2005, 19:20

:=BTW, anyone know why is the BSAC ERD so expensive anyway?

From the mail shop - Course notes cost 12 pounds (and you've already got the BSAC nitrox tables, haven't you? - if not they're another 15 pounds).

What else are you paying for - the diving and the classroom time?

I've always been told it's ?180 min + boat diving costs for you + instructor/s
(I count that as expensive compared to other SDCs)
& branches can't run it, only schools....
I'll go check the POE for this year's details

David Walker

05-01-2005, 22:34

& branches can't run it, only schools....

If it is only schools that can run it (is that really true???) then you'll be paying for the instructor's time, which presumably brings it up closer to the cost of the other commercial training agencies anyway (TDI, IANTD, etc) and so might as well go and do one of those.

David

Nigel Hewitt

06-01-2005, 08:42

& branches can't run it, only schools....

Why do I find that strangely disturbing?
Are there other courses aimed at the commercial training market that I didn't know about?

nick kay

06-01-2005, 12:31

I've always been told it's ?180 min + boat diving costs for you + instructor/s
>> I was charged ?186 which included all instructor costs:
Grame Bruce drove from Durham to Capernwray & paid his own entry for the 1st training/practical/assessment
We then used his/Scottish Dive Centre's RHIB for the two days of open water diving - he paid to drag it there & the fuel...
I'd say that was value for money

nick kay

06-01-2005, 12:34

& branches can't run it, only schools....

Not sure thats true - it might be more likely that the only Instructors that are qualified are part of schools...

I'm trying to do my observe/assist/instruct for ERD this year and I'm not part of a school/shop & haven't been required to be so...

"trying" because there are few ERD courses running (bit like trying to get on an ITDC - but thats a completely different "moan")

iainmsmith

06-01-2005, 12:59

& branches can't run it, only schools....

Not sure thats true - it might be more likely that the only Instructors that are qualified are part of schools...

Branches cannot run the course - it's a School/Regional only course.

From the syllabus:

"This course is run only by the BSAC Coaching Scheme or by selected BSAC Schools"

Iain

nick kay

06-01-2005, 13:08

From the syllabus:

"This course is run only by the BSAC Coaching Scheme or by selected BSAC Schools"

OK, so it can be run as a "Regional Course", but doesn't have to be run by a school

Andy Wade

06-01-2005, 14:57

:=From the syllabus:
:=
:="This course is run only by the BSAC Coaching Scheme or by selected BSAC Schools"
:=

OK, so it can be run as a "Regional Course", but doesn't have to be run by a school.

So you could run it 'In house' within your branch with the sanction and help of your Regional team, assuming they are willing and available.

nick kay

06-01-2005, 15:03

So you could run it 'In house' within your branch with the sanction and help of your Regional team, assuming they are willing and available.

That's my understanding. To the best of my knowledge, in the Yorkshire Region we have one qualified ERDi, one waiting to do his final "assessment" and 1/2 of us waiting to start the process. But with a limited number of courses running each year...

janos

06-01-2005, 19:54

Alan Ewart

06-01-2005, 20:37

:=& branches can't run it, only schools....
:=

"This course is run only by the BSAC Coaching Scheme or by selected BSAC Schools"

Iain

So a member of regional coaching team could run it for the Branch???

nick kay

06-01-2005, 23:14

:="This course is run only by the BSAC Coaching Scheme or by selected BSAC Schools"
:=
:=Iain

So a member of regional coaching team could run it for the Branch???

That would be my interpretation - and as I said in another post, I'm trying to do observe/assist/instruct for ERD this year and no-one has said no...

nick kay

06-01-2005, 23:16

You need to have an approved ERD instructor, however these are relatively few. My branch has organised an ERD course in May with Jack Ingle. I'm not the one that's co-ordinating it this end, but the fella is basically emailed the club, found out who was interested, contacted Jack, and then sorted out dates.

Thats the biggest problem... And, because so few run, its difficult to do the necessary observe/assist/instruct/boss to get the certification, i.e. its at least 3 if not 4 ERD courses...

janos

06-01-2005, 23:26

So a member of regional coaching team could run it for the Branch???

That's what's happening with my branch.

Laters,
Janos

Richard Greenwood

07-01-2005, 18:48

BSAC ERD is most likely the cheapest but it neglects the detail included in the tech agency courses. Specifically deco planning software is used to cut accelerated schedules, which is a pain if all you have is a set of printed Buhlmann's.

Depends on the instructor, though. As I'm sure Nick will agree with me, as we did our courses with the same instructor, if you get the right instructor they will go beyond the ERD syllabus if you show enough interest in the subject.

matt

08-01-2005, 11:37

Depends on the instructor, though. As I'm sure Nick will agree with me, as we did our courses with the same instructor, if you get the right instructor they will go beyond the ERD syllabus if you show enough interest in the subject.

Well here is an idea. Why don't we put EAD and Buhlmann tables into the syllabus like everybody else. In fact let's put it into Adv Nx and I can stop repeating myself after that first deco dive when they ask, why is my computer so far off plan, and how do I write up a sensible backup slate?

nick kay

09-01-2005, 11:37

Well here is an idea. Why don't we put EAD and Buhlmann tables into the syllabus like everybody else. In fact let's put it into Adv Nx and I can stop repeating myself after that first deco dive when they ask, why is my computer so far off plan, and how do I write up a sensible backup slate?

>> (1) I teach Advanced Nitrox (ANx). I'm not sure what would be the value of adding in EAD...
(1a) IMHO the purpose of ANx is to introduce divers to Nitrox and allow them to select their own mix and safely deco using Nitrox, then EAD (IMHO) would complicate the course
(1b) IMHO if you want to accelerate your deco, use higher mixes then do the ERD course

>> (2) FWIW If I'm diving "ERD or Trimix rules", then I dive according to a runtime slate calculated via ProPlanner. However, I also use an air computer and an air integrated nitrox computer. Should either of this insist on deco over & above the runtime slate, I'd normally clear the computer(s) before surfacing. However, as I run ProPlanner on 20/20 safety factors, the slate (ProPlanner) and the computers are not disimilar (ProPlanner is normally more conservative)

TerryH

09-01-2005, 14:36

matt

09-01-2005, 16:02

:=Well here is an idea. Why don't we put EAD and Buhlmann tables into the syllabus like everybody else. In fact let's put it into Adv Nx and I can stop repeating myself after that first deco dive when they ask, why is my computer so far off plan, and how do I write up a sensible backup slate?

>> (1) I teach Advanced Nitrox (ANx). I'm not sure what would be the value of adding in EAD...

It makes planning a whole lot easier. Without EAD a separate table is required for each and every mix.

(1a) IMHO the purpose of ANx is to introduce divers to Nitrox and allow them to select their own mix and safely deco using Nitrox, then EAD (IMHO) would complicate the course

Well I would consider Basic Nitrox as providing the introduction. Advanced is (or should be) concerned with teaching the additional theory required to use 'custom' mixes and introduce safe decompression using higher FO2 gases. EAD is pretty useful when dealing with custom gasses, particularly when you get one other than ordered.

My big problem with BSAC Adv Nx is that it is taught using a set of tables which most decompression divers would not use (and by most we are talking World wide). BSAC accept that people are going to use NX dive computers (which are generally EAD based), but teach using tables which have no resemblance to the profiles those computers will produce once they enter deco mode.

How exactly do we expect people to accurately calculate gas requirements when their computers are going to need significantly more deco than Nx 88s. Well the answer I came up with is pretty simple. Get a set of Buhlmann's and apply EAD. The profile will be pretty similar to a U-Profile on the majority of modern dive computers.

(1b) IMHO if you want to accelerate your deco, use higher mixes then do the ERD course

Agreed. Oddly, having completed BSAC ERD a diver can quite easily find their accelerated deco times (calculated on proplanner) longer than non-accelerated 88 times.

By sticking with 88s we introduce practical problems at Advanced and present illogical theory at ERD.

>> (2) FWIW If I'm diving "ERD or Trimix rules", then I dive according to a runtime slate calculated via ProPlanner. However, I also use an air computer and an air integrated nitrox computer. Should either of this insist on deco over & above the runtime slate, I'd normally clear the computer(s) before surfacing. However, as I run ProPlanner on 20/20 safety factors, the slate (ProPlanner) and the computers are not disimilar (ProPlanner is normally more conservative)

Personally when Nx diving I carry 1 mixed gas computer, 1 slate (bailout on the back), 1 D-Timer and a set of submersible tables with air + 80. In conjunction with EAD that provides a redundant method of exiting pretty much any Nx eventuality - whether I have overstayed or aborted early. Trimix is by necessity a little bit more complicated.

nick kay

09-01-2005, 19:35

It makes planning a whole lot easier. Without EAD a separate table is required for each and every mix.
>> But the whole point of the BSAC EAN tables, is that you don't need to do the calc...

My big problem with BSAC Adv Nx is that it is taught using a set of tables which most decompression divers would not use (and by most we are talking World wide). BSAC accept that people are going to use NX dive computers (which are generally EAD based), but teach using tables which have no resemblance to the profiles those computers will produce once they enter deco mode.
>> Accepted, but (expects a flame war...) once most people have done Nitrox, I'll bet:
(1) They only check their MOD
(2) They don't calculate CNS or UPTDs
(3) They don't calculate air requirements
The people that do the above and USE nitrox are probably doing ERD type dives, reasonable/significant deco and are/should be diving to ERD "rules"/techniques
Therefore, doesn't the BSAC Advanced Nitrox course deliver "what it says on the box"???

How exactly do we expect people to accurately calculate gas requirements when their computers are going to need significantly more deco than Nx 88s. Well the answer I came up with is pretty simple. Get a set of Buhlmann's and apply EAD. The profile will be pretty similar to a U-Profile on the majority of modern dive computers.
>> OK, so add it into ERD

:=(1b) IMHO if you want to accelerate your deco, use higher mixes then do the ERD course

Agreed. Oddly, having completed BSAC ERD a diver can quite easily find their accelerated deco times (calculated on proplanner) longer than non-accelerated 88 times.
>> Thats generally what I find - at least if you run the safety parametrs greater than 15/15

Personally when Nx diving I carry 1 mixed gas computer, 1 slate (bailout on the back), 1 D-Timer and a set of submersible tables with air + 80. In conjunction with EAD that provides a redundant method of exiting pretty much any Nx eventuality - whether I have overstayed or aborted early. Trimix is by necessity a little bit more complicated.
>> Sorry, should have said:
(1) The air computer is used as a D-Timer
(2) Yes, I carry different options, bailouts and KYAG sheet
(3) I agree - Trimix gets fun when you're carrying a back-mix and two different side deco gases - all those lovely calculations & options... GAP is great for a "sanity check"

David Walker

09-01-2005, 19:58

>> Accepted, but (expects a flame war...) once most people have done Nitrox, I'll bet:
(1) They only check their MOD
(2) They don't calculate CNS or UPTDs
(3) They don't calculate air requirements

To be fair the reason most people don't explictly sit down and work out how much air they'll use to the litre is because its blatantly obvious having done a few dives how much you need. If you regularly do 30m dives for 30mins say, there's no point in working it out each time because you've done it before. Equally, if you know you've got plenty of reserve for the 30m dive, you won't necessarily need to sit and work out the difference for a dive to 32m.
Same with tox units - if you are a million miles away from the limits on your usual diving, there's little point in knowing it exactly for each dive.
Even MOD, you probably do think about it but again I bet most don't sit and work it out on a bit of paper, its numbers you use all the time and just know them.

David

tristan green

11-01-2005, 03:54

Even MOD, you probably do think about it but again I bet most don't sit and work it out on a bit of paper, its numbers you use all the time and just know them.

David

But doesn't everyone analyse their nitrox and write their name, the O2 percentage and MOD on the tank before using it?

I know that I have to use a calculator to work up the MOD from the percentage each time, but then maybe I'm not diving it regularly enough with the same mix every time. Granted if I only ever used the same mix for every dive and the analysis was within a percentage then I'd probably stop using the calculator.

Regards,
Tristan

Nigel Hewitt

11-01-2005, 09:27

But doesn't everyone analyse their nitrox and write their name, the O2 percentage and MOD on the tank before using it?

No. Mine just get marked with the mix percentages. The MOD is part of the plan and I make sure my cylinders stay with my kit.
Some things are far to important to trust to a sticky label.

iainmsmith

11-01-2005, 11:36

:=Even MOD, you probably do think about it but again I bet most don't sit and work it out on a bit of paper, its numbers you use all the time and just know them.
:=
:=David

But doesn't everyone analyse their nitrox and write their name, the O2 percentage and MOD on the tank before using it?

To my mind, the FO2 is useless information underwater, as it doesn't tell me anything useful without me having to think aobut it a little. The MOD, on the other hand, is written in very large letters on the tank. That way, I look at the tank, look at my gauge and if the number on my wrist is less than or equal to the number on my tank, I can breath it safely.

The only tank that has anything other than my name and MOD on it is oxygen, which has "OXYGEN" written on it in big letters for two reasons:
1) I really, really, really don't want to breath it at 21m by mistake!
2) If needed on the surface for additional gas in the event of an incident, it's very obvious to everyone on the boat what is actually in the cylinder.

But yes, I do analyse every tank of nitrox/oxygen. Just in case someone has slipped up.

Iain