The diving system on the Benthic Explorer was a saturation system, meaning the divers were expected to absorb the maximum amount of inert gas during any given dive. That meant that the decompression time required to rid themselves of the inert gas would be the same no matter how long they stayed at pressure. The system was composed of three cylindrical deck decompression chambers (DDC), each twelve feet wide and twenty feet long. The DDCs were hooked together like enormous sausages with double pressure hatches separating them. Within each were four bunks, several fold-down tables, a toilet, a sink, and a shower.

Each DDC also had an entrance port on the side and a pressure hatch on the top where the diving bell, or personal transfer capsule (PTC), could mate. Compression and decompression of the divers took place in the DDC. Once they had reached the equivalent pressure of the depth where they were to work, they climbed up into the PTC, which was then detached and lowered into the water. When the PTC reached the appropriate depth the divers opened the hatch through which they’d entered the bell and swam to the designated workstation. While in the water the divers were tethered with an umbilical cord containing hoses for their breathing gas, for hot water to heat their neoprene dry suits, for sensing wires, and for communication cables. Since the divers on the Benthic Explorer used full face masks, communication was possible, although difficult, due to voice distortion in the helium-oxygen mixture they breathed. The sensing wires carried information about each diver’s heart rate, breathing rate, and breathing-gas oxygen pressure. All three levels were monitored continuously on a real-time basis.

Larry looked up from his desk and regarded his second team of divers with disdain. He couldn’t believe how slovenly, brazen, and unprofessional they invariably appeared.