I only mentioned the police divers used air in excess of 40m because someone else posted that at that depth He must be used. I live on the edge of the lake district where drownings are not uncommon and there are occasionally deep police searches. My computer (Zoop Novo) gives the max depth on air as 62m so there must presumably be some circumstances when air can be used at that depth or has Sunnto got it wrong?.
This thread reminds me of the Aviva insurance advert - all someone asks for is a quick bit of information - a quote - then what they get is a quiz.
I do actually agree with most of what most posters have written, but it just does not answer my original as to where dive tables can be found. Just because someone makes enquirers for information to assist in the assessment of the feasibility of something does not mean they are about to embark on that thing without proper research and training. I have now pretty well decided that any form of decompression diving is not really for me. I will probably look at carrying more air or lean nitrox to extend my dive time right up to my NDL and have plenty in hand for a slow ascent.
Incidentally I recently saw and an uncontrolled ascent from about 28m at the end of the dive on nitrox 32. We had all gone to the shot line (I was part way up) when a diver shot up like a rocket in a stream of bubbles. When back on the boat he said that being in a bunch of divers [on the shot line] and in all the bubbles had confused him, he had pressed and held in the inflate on his BCD. He was still OK about an hour afterwards, but as this was a holiday dive group I will never see him again to know if there were any long term effect. Whilst on these dives I heard that there is now a recommendation that for dives in excess of 20 m a minimum 1 minute deepstop is taken at about 11 or 12m, anyone else heard this?