WHAT COLOUR IS YOUR DIVING?
BLUE WATER
Archetypal tropical reef diving. Temperature range of 73-85F (23-29C), usually excellent visibility of 65-100ft, reef building corals and colourful fish – a universal comfort zone.
GREEN WATER
This colour usually betokens a temperate environment, such as the UK – cooler water (40-70F / 5-20C) rich in plankton and oxygen.
BLACK WATER
A night dive carried out over abyssal water to observe the vertical migration of deep water creatures.
CAVERN
An overhead environment dive, in which the opening is always within sight and easy access.
A fuller exploration
CAVE
deep into a flooded cave system, with no immediate means of exit.
Taking advantage of tide or current to carry you along the reef.
Diving over black volcanic sand or coral rubble in search of unusual small creatures.
Any dive after sunset, torches essential.
DRIFT MUCK NIGHT TECHNICAL
Dives deeper than 165ft that demand specialist training and equipment, in particular the use of trimix breathing gas and closed circuit rebreathers.
Diving around or into shipwrecks (penetration), which demands advanced navigational skills and becomes more exacting if you venture inside.
WRECK LIVEABOARD STANDOFF
The Galapagos Islands vs Shetland
GO GLOBAL
The Galapagos Islands are high on the bucket list of most divers, largely due to the schools of hammerhead sharks that gather in the remote northern islands, accessible only by liveaboard dive boat.
STAY AT HOME
With its mosaic of islands and undiluted nature, Shetland is Britain’s own Galapagos. Underwater visibility is often superb, reaching 65ft or more. There are, admittedly, no hammerhead sharks – but you can explore the twilight world of sea caves and marvel at schools of saithe and pollock as they stream around the reefs. Shetland evokes a strong sense of nature untrammeled; it will take your diving to a higher latitude.
If conditions allow, your liveaboard may head to Out Stack, the northernmost rock in the British Isles; its ravine is packed with the most colourful dahlia anemones I have seen. Nearby at Balta Sound, there is the strangely beautiful wreck of the British submarine HMS E49; the sub lies on a bed of pure white sand, a memorial to the 31 crew who died when it struck a mine in 1917.
DIVE DEEPER
MV Valkyrie liveaboard (mv-valkyrie.co.uk); also based in Orkney – see above.
Simon Rogerson is the editor of ‘SCUBA’, the official journal of the British Sub-Aqua Club