What is the reality of diving in Loch Carron or Loch Alsh? What happens physically when we slip below the surface? Why do we dive?

Man goes into the sea for food, treasure, military operation, sport and exploration.

Diving is not a recent activity: Herodotus tells of Scyllius used by Xerxes to dive for treasure on sunken Persian galleys. Another Greek historian, Thucydides, mentions the use of divers in the Athenian attack on Syracuse to saw through barriers built below the surface to obstruct and damage Greek ships.

It was not until 1943, however, that Cousteau and Emil Gagnan successfully demonstrated the 'Aqualung' (a demand-regulator controlled by the diver) from a concept devised in 1865 by Rouquayrol and Denayrouse. This self-contained underwater breathing apparatus (SCUBA) is the direct ancestor of the modern demand valves, which swarm around Skye and Lochalsh from Easter until October. This 'personal' equipment allows much more freedom of movement, enabling the diver to dispense with cumbersome air pumps and restrictive umbilicals. The development opened the floodgates to what is now termed the 'sport-diver'.

He or she is an enthusiast who at every available opportunity is seen leaping overboard from an ever-growing host of rubber dinghies or the ever more popular dive charter boats. Kyle of Lochalsh has been a stop-off point for charter boats for some time with the 'Port Napier' continuing to draw the keen amateur from all over the UK.

But what is it like down there? Loch Duich, unfortunately, is not Ras Mohammed, but the West Coast of Scotland has some of the finest diving in Western Europe: above-average visibility in open sea combined with a wealth of marine fauna ensure a worthwhile and enjoyable dive at most localities. Light, alas, even in the clearest water, is selectively absorbed with increasing depth until at about 30-35m everything appears blue or bluish grey-green. This can be redressed by introducing artificial lighting and the underwater explorer can find himself swimming through seaweed forests of fronds with such exotic sounding names as sea lettuce, peacock tail, devil's arrow and mermaid's fishline.