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Dan Volker <dlv@ga*.ne*> writes: > >When is the safety diver put into the water? > > They should go in at the predetermined point that the divers will reach > their first safety stop. If we say we will do 26 minutes at 260 fsw, then > around 27 minutes later, the safety diver should be making their way down > the float ball line to the predetermined first stop depth. In this case, would you have the safety diver mix back gas for 260, with plans to head down the line if no divers arrive by a certain time, or is the safety diver strictly limited to the planned first stop depth? > ... During the entire dive is not > usually procedure, though with students in the water, I would consider it > smart for IANTD or TDI to mandate this on all instructor/student training > dives below 200 feet. In areas where there is a large current, this may > require a scooter for the safety diver to maintain position overhead of the > divers---skin friction drag on the bottom can create significantly less > current on the bottom, not to mention the occasional shear currents where a > surface current carries the safety diver south, while the divers on the > bottom are carried north. I would say a training dive should be aborted in > this scenario. If a second instructor or other competent person is going to run with the group the whole time, wouldn't it make more sense to do so with the group on the bottom than solo and well overhead, both to be able to help the students more quickly and to be able to be helped if this safety diver has a problem? > >I am interested in knowing how one can determine the exact amount of > >negative buoyancy a wet suit (i.e. uncrushed neoprene) can have at > >depth. > > I have a simpler solution. Just assume it will have no buoyancy at all on > the bottom ... And then there's the even simpler solution of not using neoprene suits, especially wetsuits, on deep dives. The amount of bouyancy skew between the surface and depth is something that could be better handled by ideally a non-neoprene drysuit (better warmth at depth, better bouyancy characteristics, and backup bouyancy in case of a wings failure, all in one package). -- Anthony DeBoer <adb@on*.ca*> -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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