Deco Questions

[Martin]

Good Morning.

It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.

I can, however, find no reference to this in the instructor manual.

Can anyone shed any light on the matter???

Thanks
MArtin

[David Walker]

It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.

Never heard of that before - maybe it's just something your branch's instructors like you to get right?

David

[John Williams]

:=It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.

Never heard of that before - maybe it's just something your branch's instructors like you to get right?


Not to mention the DDRC and ny other chamber thaat you might need to call upon if you get it wrong!

As an aside - if Ocean diver teaches you the MUST know information about diving ...and this gets built on progressively with SHOULD know information as you progress through the grades to where many exam questions centre on the COULD know information....

Well if Ocean Diver is the MUST know....why is the pass mark not 100%? ...which bits of the MUST know stuff can you afford to miss out?

John

[PeteM]

Well if Ocean Diver is the MUST know....why is the pass mark not 100%? ...which bits of the MUST know stuff can you afford to miss out?

Surely that is why an OD can only dive under the supervision of a Marshall.

[Dave]

:=:=It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.
:=

Nope. There is nothing in the rules of the exams that requires anything other that a straight 80% pass.

Well if Ocean Diver is the MUST know....why is the pass mark not 100%? ...which bits of the MUST know stuff can you afford to miss out?

How about because BSAC is incapable of writing exam papers where all the questions are both unambiguous and where the correct answer given by BSAC is the same which is the logically correct one as given by the question wording

Dave

[J Abbott]

It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.

And whilst we are on the subject, let?s challenge a diving fundamental truth. Why do we need to teach tables at Ocean Diver any way? Should we not be encouraging the use of computers? It is a standard of at least one recreational agency that basic courses are taught with computers. Use of tables is taught at the next level. Once understood, the computer is less prone to operator error than tables and I certainly know of some individuals who could no longer use the tables safely.

Cost is a big factor but the second hand market might lend a hand. Club equipment might need to include computers in their range of loan/hire equipment. These are really just logistical aspects.

Our training scheme ought to recognise that some divers would prefer to learn to dive without studying dive tables and are more than happy to pay for the alternative. In my experience such individuals forget how to use the tables almost as soon as the exam paper is marked. It makes teaching the tables nugatory effort. So why to we do it?

John

[iainmsmith]

:=It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.
:=
And whilst we are on the subject, let?s challenge a diving fundamental truth. Why do we need to teach tables at Ocean Diver any way?

Because not all divers can afford to have a computer from day one and not all Branches can afford to supply such.

Secondly, actually having to look at the tables at least makes the diver think (even if briefly) about planning the dive, whereas diving a computer does not.

Also, computers break (mine has failed underwater twice, plus once on the surface) - one could draw an analogy - why does the British army still teach navigation by map and compass, when GPS is freely available? Because sometimes technology lets you down. Knowing the non-battery-operated basics means that you can work around the problem.

Personally, I think the '88s are far too aggressive, but in terms of ease-of-use, it doesn't get much better.

Iain

[iainmsmith]

:=:=:=It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.
:=:=

Nope. There is nothing in the rules of the exams that requires anything other that a straight 80% pass.

:=Well if Ocean Diver is the MUST know....why is the pass mark not 100%? ...which bits of the MUST know stuff can you afford to miss out?

How about because BSAC is incapable of writing exam papers where all the questions are both unambiguous and where the correct answer given by BSAC is the same which is the logically correct one as given by the question wording

Coke Alert!

But nonetheless a fair point.

However, the question is a valid one. I know of at least one agency where the student requires 100% in "safety critical" questions. IMO, deco and gas planning would certainly come under that heading. I know that some years ago this approach was taken in my Branch, but we stopped doing it when I became TO and discovered that we weren't supposed to. That didn't mean that I disagree with the concept, though.

Iain

[J Abbott]

=Why do we need to teach tables at Ocean Diver any way?

Because not all divers can afford to have a computer from day one and not all Branches can afford to supply such.

So introduce a system that allows teaching of tables or computers but don't make tables compulsory.


Secondly, actually having to look at the tables at least makes the diver think (even if briefly) about planning the dive, whereas diving a computer does not.

The DM should make sure the buddy pair have planned the dive and if they use computers they don't have to look at the tables any way.


Also, computers break (mine has failed underwater twice, plus once on the surface)

So teaching tables is for backup?? Well its not much of a back up if it is forgotten the instant the exam is passed.


Personally, I think the '88s are far too aggressive, but in terms of ease-of-use, it doesn't get much better.

Absolutely!!

[iainmsmith]

:==Why do we need to teach tables at Ocean Diver any way?
:=
:=Because not all divers can afford to have a computer from day one and not all Branches can afford to supply such.

So introduce a system that allows teaching of tables or computers but don't make tables compulsory.

So what if half your course can afford computers and the other half can't? How do you assess the ability of those who have learned tables without asking exam questions? And if you ask those questions, how do you avoid discriminating against those who haven't turned up to those lectures?

:=Secondly, actually having to look at the tables at least makes the diver think (even if briefly) about planning the dive, whereas diving a computer does not.

The DM should make sure the buddy pair have planned the dive and if they use computers they don't have to look at the tables any way.

:=Also, computers break (mine has failed underwater twice, plus once on the surface)

So teaching tables is for backup?? Well its not much of a back up if it is forgotten the instant the exam is passed.

In which case it's not being taught properly and/or the students are being given the impression that they need to know this only to pass the exam and that they can go off and dive their computers the moment the exam is over. Also, to extend your DM analogy, the DM should be ensuring that the divers have a plan to get out of the water in the event of a computer failure.

Knowledge is rarely a bad thing. Just as they still teach basic arithmetic in schools, despite the availability of computers and calculators, so it makes sense to teach the basics of decompression planning before introducing the shortcuts.

Iain

[Martin]

Seems something which has just been done in our branch for a while, and after I did an assistant instruct on a combined EANx course at the weekend, seems to be something which is going about in other branches aswell.

Seems an entirely sensible situation to me, and I think a branch/instructor is entirely at liberty to stipulate additional requirements, however, just so I know the situation incase a clue-d up trainee were to be insistant.

Thanks.

:=It seems that there has been a long standing trend that in exams, whilst the overall passmark is pre-set, the decompression/tbales related questions must all be 100% correct.

Never heard of that before - maybe it's just something your branch's instructors like you to get right?

David

[PeteM]

I think a branch/instructor is entirely at liberty to stipulate additional requirements, however, just so I know the situation incase a clue-d up trainee were to be insistant.

Nope. A branch or insructor is specifically EXCLUDED from adding additonal requirements, from the branch officers hand book "A Branch Diving Officer, BSAC Branch or BSAC School shall not add to or subtract from the BSAC's training and qualifying requirements for any diver qualification"
<a href="http://www.bsac.org/branchmanage/421training.shtml#content" >http://www.bsac.org/branchmanage/421training.shtml#content</a>

So whilst the DO can legitimately stop someone going on a dive because their knowledge is inadequate they can not refuse to award a qualification where someone has reached the HQ set standard of 80%

[MattS]

And whilst we are on the subject, let?s challenge a diving fundamental truth.

Ok lets.

Why do we need to teach tables at Ocean Diver any way?

I can think of a lot of reasons, Iain has covered most of them. Tables underllie computers, they are the common denominator and so should be taught first. From a practical teaching perspective, we can teach one table and provide trainees with an effective method of planning, without having to know the details of the many different computers available.

Should we not be encouraging the use of computers?

I am not sure we need to encourage it, it is almost inevitable that divers are going to buy them and use them.

Our training scheme ought to recognise that some divers would prefer to learn to dive without studying dive tables and are more than happy to pay for the alternative.

Whilst they may wish to dive without having to learn tables, can we justify it as safe. Even when a computer is used, best practice is to carry an alternative method of calculating decompression.

In my experience such individuals forget how to use the tables almost as soon as the exam paper is marked.

You can apply the same arguments to mask clearing and reg retrieval - it still would not be right to qualify divers that have failed to demonstrate competancy.

It makes teaching the tables nugatory effort. So why to we do it?

So I am not going to question the teaching of tables at entry level. Using tables is a fundamental skill and should be taught on the fundamental course, IMVHO.

What I question is the relevance of BSAC 88 tables in todays diving. With fewer and fewer divers willing to use BSAC 88s, is it about time we adopted a more popular decompression table such as Buhlmann? At the very least the Buhlmann tables would provide times similar to those produced by virtually all dive computers, and all but the most cutting edge desktop deco packages. They are also compatible with EAD, so arguably better suited to Nitrox.

In fact I find it very hard to square that the ERD course teaches the use of Buhlmann based decompression software without teaching the tables the software is based on. I only wonder what decompression procedures the forthcoming Trimix and Rebreather courses will use.

I realise that the technical courses are way above OD, but in all other cases BSAC courses build on the fundamentals taught in OD.

So to summarise. I do think we need to teach tables and we need to do it from the first course. However I believe that spending so much time on 88s does not do BSAC divers amy favours, as so many will assign them to the bin and adopt Buhlmann anyway.

Regards
MattS

[David Walker]

However, the question is a valid one. I know of at least one agency where the student requires 100% in "safety critical" questions. IMO, deco and gas planning would certainly come under that heading. I know that some years ago this approach was taken in my Branch, but we stopped doing it when I became TO and discovered that we weren't supposed to. That didn't mean that I disagree with the concept, though.

You can't have a 100% pass mark without some much better exam papers. Look at the errata pages for Advanced Diver papers and I think there are more questions with problems than ones which are all fine - OK some are minor mistakes, but others are major changes to the questions. If the pass mark was to increase we really need some proper quality control before these things are released.

And something I was thinking a while ago, assuming now that most problems have been found (although of course there are still a lot of ambiguous questions) how about making corrected versions of the exam papers available to clubs / instructors? With a lot of the changes, you are changing the 'correct' answer to make it, well, correct... if we do all the changes manually we end up giving students a paper covered in scribble, where usually the 'corrected' answer is the right one. BSAC could change the originals easily, chuck it on a CDR (~10p now?) and post one to each registered instructor (30p for a stamp, 10p for an envelope?) 50p per club and we'd at least have papers that look like they come from a major diving organisation.

But getting back to the point, I don't think 100% is really necessary to prove the knowledge, although I haven't checked the balance of the questions. Basically, if someone can get 9 out of 10 questions on tables/deco correct, then they clearly understand how they work and probably made a simple mistake (much more likely in an exam when you're trying to work out and think about 5 different 'dives' at the same time). Obviously if they got every question about deco wrong, but that still got them above the pass mark then that's more worrying - but hopefully something that the instructor would notice and correct. Something like that I believe would be a valid reason for a DO to withhold a qualification until they have got that knowledge, even if they've done all of the components of the course. Often you'll find that if you ask someone what they think the answer to a particular question is after they've done the exam, they'll either get it right (just through thinking about it), or have a very good reason for saying something else - usually on the ambiguous questions.

David

[David Walker]

Also, to extend your DM analogy, the DM should be ensuring that the divers have a plan to get out of the water in the event of a computer failure.

Tables - good, for a graphic understanding of how depth and time affect your dive. Good for clubs where divers don't have computers.

BUT... I don't know anyone at all, and have never ever seen anyone, plan a dive on tables (and certainly not BSAC tables) as a 'backup' and then dive on their computer. If you're using a computer the tables are going to be so far out even by the time you reach the bottom it's not really worth having.

Consider having a backup on tables for a 32m dive (in reality it's a wreck in 25-32m), but you dive with your computer. Done a lot of dives like that, and the majority of those we were leaving the bottom at around 40mins, just about to go into deco - probably 42 by the time we reach the first stop. That would be fine with your computer. But what when your computer fails? Well if you use tables then you suddenly have 20 minutes of deco to do... a big jump just because of a computer failure!
So what if your computer fails? If you're an OD (and so not in deco) as soon as you notice you abort the dive safely (slow ascent, safety stop). If you're doing a dive and you know you're in deco, or would be close to deco, ascend to your stop, stay there for a 'reasonable' amount of time - what is reasonable, well that depends on the dive.
Personally I believe I would be able to get out of the water safely (and within what the computer would have allowed) from any dive I have ever done if my computer failed at any point in any of those dives.


So yes, tables have their place. Their relevance to dive planning (or rather backup) when diving with a computer I think is highly questionable.

David

[iainmsmith]

:=However, the question is a valid one. I know of at least one agency where the student requires 100% in "safety critical" questions. IMO, deco and gas planning would certainly come under that heading. I know that some years ago this approach was taken in my Branch, but we stopped doing it when I became TO and discovered that we weren't supposed to. That didn't mean that I disagree with the concept, though.

You can't have a 100% pass mark without some much better exam papers.

I am not disputing your comments regarding quality of exam papers. For some years, my Branch has been using papers which had their origin in a set of BSAC "official" papers, which a number of our instructors went through and either fixed or got rid of bad questions.

&gt; we'd at least have papers that look like they come from a
&gt; major diving organisation.

There's nothing stopping you editing the existing papers in-house, although it would be nice if it weren't necessary!

But getting back to the point, I don't think 100% is really necessary to prove the knowledge, although I haven't checked the balance of the questions. Basically, if someone can get 9 out of 10 questions on tables/deco correct, then they clearly understand how they work and probably made a simple mistake (much more likely in an exam when you're trying to work out and think about 5 different 'dives' at the same time).

In which case there is, as you suggest, the opportunity to review that particular question with the student. It may well be, however, that it was the most involved question that they got wrong...and unfortunately, you can't afford to make mistakes when it comes to the most involved dives. However, if a "100%" requirement were introduced for any section of the paper, it would seem reasonable to allow extra time so that the student has the opportunity to triple-check their working if desired.

Iain

[Martin]

BSAC could change the originals easily, chuck it on a CDR (~10p now?) and post one to each registered instructor (30p for a stamp, 10p for an envelope?) 50p per club and we'd at least have papers that look like they come from a major diving organisation.

Erm ......
How many branches???
How many instructors????

That would cost thousands.

The instructors resource centre would be ideal - it could be closed to only instructors, and then all the instructional materials could be made available. In this way, we could just download updated info directly, without the trainees being able to cheat!

[Dave]

Seems an entirely sensible situation to me, and I think a branch/instructor is entirely at liberty to stipulate additional requirements, however, just so I know the situation incase a clue-d up trainee were to be insistant.

As pointed out, it is not permitted to change the requirements and I think it is dire that anyone would deliberately intend to continue to break such rules and enforce additional requirements unless a trainee happens to have the knowledge that such things are against the rules.

The BSAC qualification requirements are set by BSAC not by the whims of specific instructors / DOs / Branches

Dave

[PeteM]

Personally I believe I would be able to get out of the water safely (and within what the computer would have allowed) from any dive I have ever done if my computer failed at any point in any of those dives.

Tend to agree - and anyone that is so unsure of their status that they don't think this is probably not monitoring the dive well enough which is a whole new issue

[MattS]

The instructors resource centre would be ideal - it could be closed to only instructors, and then all the instructional materials could be made available. In this way, we could just download updated info directly, without the trainees being able to cheat!

A closed web site would need development work. A halfway house might be BSAC sending out ammended papers in response to an e-mail request from a registred instructor, or possibly a branch officer. AFAIK the components to use e-mail are already available and only need an adequate working procedure.

[matts]

:=Personally I believe I would be able to get out of the water safely (and within what the computer would have allowed) from any dive I have ever done if my computer failed at any point in any of those dives.

Tend to agree - and anyone that is so unsure of their status that they don't think this is probably not monitoring the dive well enough which is a whole new issue

OK what am I missing? We teach 'Plan the dive, dive the plan.' If you do so there is no need to 'guess'

I carry a set of tables that will get me out of anything I get into. I teach others to do the same.

It is probably worth pointing out that the behaviour exhibited by a dive computer in the 25 to 35m range can be very different to how it behaves in the 35m to 50m range. Plan your dives and you will not get caught out. Rely on what you think you know about dive computers and you may well be.