The Paper falls into two parts. First, a brief description is given of the standard diving equipment, which has changed very little over a number of years, and a more detailed description is given of the compressed-air equipment which has been developed largely as a result of the 1939-45 war. The selfcontained swimmer's air breathing apparatus is now a standard issue to the Royal Navy but the surface-demand diving equipment, which is considerably lighter and consequently more mobile, is still under trial.
An indication is given of developments in underwater communications, as well as a descriptiono f underwater tools such as thaeir lift, the tunnelling lance,the submerged bolt-driving and punching gun, the air bolt, and underwater cutting and welding equipment.
The second part of the Paper deals with the technical aspects of marine salvage and gives brief descriptions of some of the practices, including underwater work, which are commonly followed in dealing with marine casualties.
The techniques are illustrated by actual examples of refloating a stranded ship,raising a wreck, dealing with an abandoned ship on fire, and identification and recovery of objects on the sea bed at depths too great for helmet divers.
