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| Originally Posted by [b Quote[/b] (Mark Chase @ Aug. 09 2003,15:07)]I dive mainly Brighton, Folkstone and Dover. However its not just the location its the type of diving. Free hang without an SMB is generaly not an option on deco dives due to heavy boat trafic and strong currents. Free hang is not an option on long deco as the effort required and the breathing controle are detrimental to good efficient off gassing.
I think the only free hang deco I have ever done was on the Thistlegorm. There were about 20 divers on the shot and it was slack water so I did the hang just off the shot. But it was only 6mins as a precaution. To acheive a steady 6mhang requires good weighting and trim yes but also breath control and constant vigulance on the depth gauge to avoid high PP02 using rich deco mix.
I have to say that the thaught of a 30 - 45min 6m hang with the penilaty of a trip to the pot or worse if you screw up just free hanging dosent bear thinking about. I only know of one diver who attempted this on the Moldavia after loosing his reel and his buddy. He did a 40min free hang. The Nimrod found him because the boat and the coast guard couldent and he was bent dispite beleiving he had done all his stops.
I think boyency control is very important especialy with reguard to proper weighting and balance and avoiding unnecessary contact with the reef, wreck, silt bed etc. It is handy fro photography and vidio as well, but all this guff about your not a good diver unless you can do a free hang deco at 6m is just to impress the numpties and serves no benificial purpose. The only divers who could do it with no effort and no constant referance to their depth gauge are possably trainers/instructors doing 100's of dives a month or lucky sods who do similar numbers. For the rest of us once a week divers it takes way too much effort to hold for a long period. |
You seem to make out that good buoyancy is some kind of voodoo art or even difficult. It isn't! It just takes a bit of practice. As far as my job allows I try to practise once a week, or at least every few weeks. It takes maybe a couple of hours out of my scedule, hardly onerous for something so important.
With decent buoyancy a full tidal breath will take you at max a quarter to half of a metre before you breathe out. Remember - no holding of breath! And remember that no special breathing pattern is needed. It's not the amount of breaths you take that governs your offgassing it's your body's makeup. You lungs can dump as much nitrogen as gets to it (short of overloading them with bubbles) - the important thing is how quickly your body can get the nitrogen out of your tissues. If the number of breaths were the limiting factor in the speed of decompression, all you'd have to do is breathe really really quickly on ascent and you'd never get bent!
The longest free hang at 6 metres I have done so far has been 20 minutes. I did it in really rough seas and it was easy. All I did was hold my hands in front of me so I could glance occasionally to see my depth and relax. I knew my buoyancy was neutral, so my buoyancy wouldn't change more than the half metre mentioned earlier. This took me roughly from 6 - 5.5m on each breath.
I don't practise neutral buoyancy to impress numpties. In fact considering some of the looks I get at the pool when I get in in my drysuit, twinset etc from the other people, shows that I am not impressing anybody! I'm doing it so that (frantically touching wood) should I lose my buddy AND my two DSMBs, unlikely as that scenario is if you practise launching one and not losing the other, the only thing I'll be thinking about whilst doing my hang is hoping the the boat/RNLI can find me, rather than wishing I'd spent more time in the pool brushing up on my buoyancy skills.
As for where good buoyancy is important, I can not believe you think it's important for not kicking the reef/wreck and not for sitting at 6 metres. On the one hand bad buoyancy may damage something on the sea bed. On the other hand bad buoyancy could result in your getting a tox or a bend. Which do you think is more important!?
Like the vast majority of things preparation in diving is everything. I used to play a lot of Rugby, and without exception all our games were won on the practise field. Diving is the same way. With practise diving is a safe, easy sport at any level. Without it - it's a lottery and you're a statistic waiting to happen.
As for the comment about 'For the rest of us once a week divers it takes way too much effort to hold for a long period.' I dive once a week, usually twice a month, and it's no effort for me. It just took a bit of practise and effort in the run up to the season, and some tune up sessions in the pool.
Chris