It was 04:00 and I woke up with a dull pain in my left forearm and pins and needles in my left hand. Bugger!

The Dives

That day I had completed two dives, the first to max depth 44m with an average depth of 38m for 27 mins and completed 31 mins of deco using 50%. The second was to a max of 26m, average 23m for 43m and a min deco ascent with deco clearing at 6m. Surface interval was 3 hours. An uneventful pair of dives from a decompression point of view. The previous day (Tuesday) I had not dived, the day before that (Monday) I only did 50 mins at an average of 21m with 10 mins on 100% O2 at 6m.

For those who are looking for a reason as to my bend, sorry, I don't have one and to be honest, the mechanism and causality for the bend is uninteresting to me in this particular case. Neither of the hyperbaric doctors here in Stromness could explain it either.

Rather, this blog is more about the decision-making processes that happened after I woke up because I believe that most divers...

¿Qué significa ser "suficientemente bueno"? Si lo piensas, "Bueno" es un término relativo porque, por definición, debe haber alguna o muchas otras cosas que no son buenas y las estás juzgando de acuerdo a tu percepción de “Bueno”.

El término 'Doing It Right' o DIR atrajo muchas críticas en los años 90 y principios de los 2000 debido a la falacia lógica que usamos a menudo para ver el mundo con opciones binarias. Si no lo estás haciendo "bien", entonces debes de estar "haciéndolo mal".

Sin embargo, una vez que evolucionamos y salimos de una visión tan infantil, nos damos cuenta de que el mundo es mucho más complejo que eso y que tales atribuciones binarias no son válidas ni son útiles cuando se trata de aprender o mejorar las relaciones. Siempre existe un compromiso, y siempre y cuando el compromiso esté informado y se entiendan las opciones, ¿por...

Many of my readers will have heard about me talk about Professor James Reason's Swiss Cheese Model and how it can be used to show how incident develop because of holes in the barriers and defences which are put in place to maximise safety.

Professor Reason's research showed that at different levels within a system, there are different barriers or defences present. e.g. organisational, supervisor and individual. However, these defences can have holes in them because the organisations, supervisors and operators are all fallible and therefore the defences cannot be perfect.

• At the Organisational level, these failures might be poor organisational culture, inadequate diver and instructor training programmes, flawed equipment certification systems e.g. CE or ISO, or misunderstood/misused reward or punishment systems e.g. QC/QA or certificates for the number of certifications completed.
• At the Supervisor level, these gaps might be inadequate supervision dealing with inexperienced...

Introduction

Ever looked back at an incident or accident to find the reason it happened and realised that you were stressed, tired or distracted and that is what caused the event? These are three of the ‘Dirty Dozen’ which human factors experts have identified as key contributory factors or precursors to incidents and accidents.

The term ‘The Dirty Dozen’ refers to twelve of the most common human error pre-conditions or precursors which lead to accidents and incidents. These twelve have been shown to influence people to make mistakes, errors or violations. The concept was developed by Gordon Dupont in 1993 and is now a key element to Human Factors in Maintenance training.

Note that these twelve are not the only factors which lead to mistakes, errors and violations, but they certainly give you a focal point to identify conditions where errors and violations are more likely to occur. Different domains or even subsets within domains like pilots, ramp crews, air...

What does ‘good enough’ mean? If you think about it, ‘Good’ is a relative term because, by definition, there must something or many things which aren’t good and you are making a judgement against your perception of good.

The term ‘Doing It Right’ or DIR attracted significant criticism in the 1990s and early 2000s because of a logical fallacy we often use to view the world in binary options. If you aren’t doing it ‘Right’ then you must have been ‘Doing It Wrong’. 

However, once we grow up from such a childish view, we realise the world is far more complex than that and such binary attributions are not valid nor are they helpful when it comes to learning or improving relationships. There is always a compromise but as long as the compromise is informed and the trade-offs understood, then why not use it? 

Unfortunately, the same binary attributions are often used for ‘safe’ in diving....

You have been blown-out for 4 weekends in a row and you now have an opportunity to dive this weekend as the weather is fabulous and the visibility has been reported as 10m+. However, you aren’t due to dive for another four weeks for a variety of reasons. Just as you getting your gear ready to put on, you notice that you have a malfunction with your gear, something manageable but will cause you additional workload and reduce your margin of safety on the dive. This is a failure you wouldn’t normally accept because you get to dive lots. If you don’t dive, your buddy will have to sit out too as there isn’t anybody else to dive with them at such short notice. What do you do?

At this point, you are managing uncertainty not a risk because the numbers are not calculable. You decide to dive and nothing adverse happens and you have an awesome dive.

Are you reflective of your management of uncertainty? Did you think it was ‘good’?

But what if two or three...

The risk of a fatality in diving has been stated as

16.4:100 000 divers (DAN Figures)
14.4:100 000 divers (BSAC Figures)
0.48:100 000 dives (DAN Figures)
0.54:100 000 dives (BSAC member dives)
1.03:100 000 dives (non-BSAC dives)
Fatalities Conference Proceedings 

but what does that mean? I can tell you that it means nothing to most people because we don’t deal with risk in the real world like that. For a start, numbers don’t have the same emotional relevance as stories, and as such, they don’t stay in our heads that long. Furthermore, most decisions are informed by emotion and not logic and the following is a classic example of the apparent irrationality of perceived risk.

A colleague of mine did a 'Discover Scuba Diving'-type dive while on a cruise to the Caribbean. Her only diving experience prior to getting into the ocean was in the swimming pool of the cruise liner she was on. Her first dive was to 30m/100ft on a deep wall in the Caribbean which was advertised...

How safe are you when you dive and how do you measure safety? Think about the following story and how safe the situation was...

Six divers had decided to undertake a 30m dive from a RHIB. John and Dave were diving as a team with their local university dive club and had over 2000 dives between them. Graham was relatively newly trained as a marshal and had not worked with Brian before. On the dive boat, there were two new divers to the club, Gail and Mark. Both Gail and Mark had successfully completed a check-out dive & dry suit familiarisation course with another instructor in the club, and they were already certified for 40m diving. Graham was keen to do a drift dive in 32m of water. Brian, the cox, was somewhat worried about the conditions as there seemed to be waves forming. However, as long as all divers were certified to 30m diving and effective at getting into the water and back onto the RHIB, he was happy that the risk was acceptable. To allow the Cox and Marshall to...

A diver qualified in the summer of 1999 while on holiday in Greece. His final dive on his PADI Open Water course was to 25m, obviously beyond the standards of this course. The instructor told him to write 18m in his logbook as they were only supposed to go to 18m. The diver didn’t know this during the dive so didn’t question the depth they dived to. Nor did they know that there was a way of providing feedback to the agency for breach of standards. In March 2005, the diver went to Cape Town with work and there was an opportunity to dive at Gansbaai so he took his OW card with him. He hadn’t dived since his OW course in 1999. There was no checking of cert cards when they got there, nor was there a skills dive to ensure everything was ok. The diver and 3 of his buddies completed a 45min 10m dive from a RHIB with no problems.

One month later the diver was in San Diego, again with work, and wanted to go diving. He had decided that one of the most important things he...