10 Advises.

10 advises to dive in security on deep wrecks

Article published in the magazine Octopus n°24 [February – March 2000]

The deep dives are special and delicate dives and no improvisation is allowed, even more on wrecks. They ask an important preparation.
It can be very tempting and easy to commit multiples mistakes. The Jose Illueca is at this title a school case. The first structures are at -76/78m. You could be tempted to dive with air. Why not? This is simpler, cheaper. And then -80 is not deep! And why not with a single cylinder?

It is interesting to note that Patrice and François already had dived on this wreck in technical classical style, with air, some years ago. The trimix allowed them to rediscover totally the wreck in optimum securities conditions.

Be serious! Here are 10 basic advises, almost of survival, to avoid doing anything stupid:

1. Plan your dive and dive according to this plan. That goes for the choice of the objective according to his training, his formation, his health, to the choice of the equipment according to this objective. And you must be able to justify all these choices, and especially not to try to take this one or that one « because it is a good one ».

2. Do not dive, therefore, without a solid basic formation, on wrecks, with mixtures. And without a long training with a heavy equipment, relays, procedures of decompression that one will lengthen only very progressively..

3. Do never go deeper than -50/60 meter with air (there is not even worthy tables). This is rather deep and is a depth range where you already can use, without shame, the trimix, according to your sensitivity to narcosis. It will allow you to manage your dive. And will reduce considerably the risk of breathlessness and the risk linked to a ppo2 excess. At last, the lucidity gain thanks to helium will have no price when, taken in a net or lost in a passageway at -75 meter, it will be necessary to react quickly and well (« What is this man’s life worth? »). You won’t go deeper than -80m with trimix. Beyond, even if that remains possible, that becomes frankly complicated: too much equipment to take, too many unknown parameters.

4. It implies, in any case, to foresee a decompression with mixtures over oxygenated (36% or 80%, pure o2 at -6m). Therefore a management of complex but precise decompression.

5. It implies also to bring along all his decompression. For example: 1 bi 12 or bi 15 bottom mixture. 1 pony bottle of nitrox 36% o2, another of 80% pure o2.

6. Always foresee a longer time. And a deeper depth in your planning. For example 5 min. and 5m more.

7. Consider these dives as under ceiling at least because of the deep stops and foresee therefore at least 1/3 of security at the bottom and for the ascend. Apply the rule of redundancy on the vital equipment.

8. Avoid to penetrate the wrecks, and do not do it without a guiding reel and a knife (or scissors) that remains the most practical for cutting a net with one hand. The reel also can unfold itself on a wreck if you want to be sure to retrieve the bout on time. It can also serve to launch a buoy. All these usages should not be improvided and are long to learn and to assimilate.

9. Foresee there more than anywhere buoys to signal yourself as soon as possible in case of loss of the line (full water), as early as the beginning of the decompression for example. Foresee also specific equipment to signal yourself at the surface from far away (rockets, mirrors…).

10. The boat, at last, must be chosen with care, as much for its capacities to welcome our heavy equipment as to react in the worse situations. You will understand the importance of an experienced and sensitized skipper to this kind of dive.