50m and more (depth of Sealab III -189m, depth of Conshelf III -100m): This depth is highly complicated. The aquanauts are saturated and demand long decompression periods of several days after the dives. Therefore it is impossible to go and come back, but one dive (exposure) should last several days. The breathing mixture consists mostly of Helium which makes communication without unscramblers impossible. The handling of pure oxygen requires oxygen-clear equipment. The aquanauts have to pass a long training program. The environment is cold and dark. Depths like this might be a target for the future, but for the beginning and especially for the purpose to attract attention it is not first choice. All these obstacles occur at all depths of more than 60m.
-50m (depth of Sealab I and II -60m): The station might be reached with easily available compressed air, but each dive requires well-planned decompression stops. Therefore there is a risk of decompression accidents. Longer stays at the station would make long decompression periods necessary. A surface support vessel, a PTC (personnel transfer capsule) and DDC (deck decompression chamber) are not nice-to-have, but strictly necessary. Divers for this depth have to be specially trained.
-20m and less (depth of Aquarius -20m, depth of Conshelf II -11m): The station is easily to reach for nearly everybody. Most decompression tables allow stays until 40 min., the ‘NOAA air deco table 2010‘ even 50 min. without being obligated to decompress (except the standard 3m safety stop).
Here is the idea:
- the station should attract scientific divers with oceanographic, psychological or other targets,
- private divers who join the special training program to enter the station for up to 30 min.,
- private divers who want to visit the site/park without entering the station,
- snorkellers who want to watch the station from the surface,
- free divers who want to visit the site/park without entering the station
To reach all these diver types we should target a depth of -20m for the first modules. Divers have 10 min. to reach and enter the station, 30 min. to stay in the station and additional 10 min. for ascent including safety stop. Stays for several hours or even days are the next strong target to be followed as soon as the station’s concept proved successful. This site would serve as an experimental ground in order to extend the depth in the future. Alternatively a ‘deep module’ (like the ‘deep lab’ in the Conshelf II project) might be installed as soon as possible near the site at greater depths while the -20m station serves as an decompression facility. With this ‘deep module/s’ we would be able to meet the requirements of scientific divers.
If we start in this manner we will have enough time to develop new strategies for additional equipments like transfer capsules, decompression chambers and additional ‘branches’ at other depths and let all interested persons participate in these processes.