Saturation diving was used extensively during the construction of the Ninian Central Platform at Kishorn. Every twelve hours, a dive team (using a system of positive and negative gas pressures within the diving system and diving bell) made an excursion from the deck of the dive support vessel to the job site below. Gas pressures within the bell and chambers were equal to the bottom depth at which the men worked.

This type of diving eliminates the need for lengthy and potentially hazardous decompression day after day. At the end of 28-30 days the whole dive system can be decompressed and the men brought back, taking approximately four days to return to the surface from 400 feet.

During their month under pressure, the men are totally dependent on the surface crew for food, drink, heating: in fact every basic requirement to sustain life. Eating, sleeping, reading, shaving and showering, etc., are all carried out within a steel chamber which in most cases resembles a small bathroom. Saturation is used mainly on oil and gas installations in the North Sea but is also used by the Royal Navy for experimental work, which leads us to another type of diving employed in the environs of Lochalsh - military diving.

Not the sinister 'frogmen' of the war years but military, usually Navy, divers working in support of the BUTEC and submarine operations.

Whether for sport or commerce divers have two things in common - an urge "to boldly go..." and the possibility of incurring one of the pressure-related illnesses - pulmonary barotrauma, gas embolism, the bends.

But that's another story.