Design Davis Submerged Escape Apparatus

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davis breathing apparatus tested @ submarine escape test tank @ hms dolphin, gosport, 14 december 1942


the dsea rig comprises rubber breathing/buoyancy bag, contains canister of barium hydroxide scrub exhaled co2 and, in pocket @ lower end of bag, steel pressure cylinder holding approximately 56 litres of oxygen @ pressure of 120 bar. cylinder equipped control valve , connected breathing bag. opening cylinder s valve admits oxygen bag , charges pressure of surrounding water.


the canister of co2 absorbent inside breathing bag connected mouthpiece flexible corrugated tube; breathing carried out mouth only, nose being closed clip. goggles provided standard part of apparatus.


the breathing/buoyancy bag fitted non-return release valve allows air escape bag user ascends towards surface , water pressure decreases. wearer can close valve on reaching surface, air in breathing/buoyancy bag serving life preserver. if bag becomes deflated while wearer on surface awaiting rescue, can refilled (for use lifejacket) opening non-return valve , blowing through mouthpiece.


the usual royal navy dsea rig included emergency buoyancy bag on front of main breathing/buoyancy bag keep wearer afloat after reaching surface if had exhausted air in breathing/buoyancy bag. emergency bag inflated oxylet canister inside - small steel oxygen cylinder opened breaking weakened neck , wrenching sharply.


it had speed-retarding drogue, rubber apron unrolled , held out horizontally wearer ascended, dramatically reducing speed of ascent through water resistance.







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