Whatever the procedure followed, the suc- 

 cessful practitioner must maintain excep- 

 tional calm as his haven fills with water and 

 he contemplates a swim to the surface. The 

 disadvantages of this procedure are de- 

 compression sickness, nitrogen narcosis, oxy- 

 gen poisoning, cold and panic. Successful sys- 

 tems must offer quick pressurization, sim- 

 plicity, protection from cold water and a 

 buoyancy device to assist ascent. 



The British Royal Navy has developed 

 buoyant ascent escape techniques to the 

 point where test escapes from a military 

 submarine have been accomplished from 600 

 feet deep. Commander M. R. Todd, R.N., (1) 

 estimates that 740 feet is certainly attaina- 

 ble, and deeper than this is a likelihood. 

 Because it is the most successful and ad- 

 vanced personnel escape system in the 

 world, wherein the occupants enter the 

 water, Todd's description of the British sys- 

 tem (Fig. 14.6) may serve as a basis for 

 comparison against the systems used in sub- 

 mersibles. 



"/t (the escape system) consists of a Sin- 

 gle Escape Tower at both ends of the 

 submarine, each fitted with the Hood 

 Inflation System (HIS) and used in con- 

 junction with the Submarine Escape Im- 

 mersion Suite Mark 6 or 7. The Escaper 

 enters the tower through the lower hatch 

 and connects his suit to 'the Hood 

 Inflation System with a simple push-in 

 plug. Through this he receives pure air 

 at 1 psi above ambient. The lower hatch 

 is then shut and the tower is flooded 

 from the sea. (The last man can complete 

 these actions by himself). The pressure in 

 the tower is then doubled every 4 to 16 

 atms in 16 seconds. The tower is cali- 

 brated to achieve this pressurization rate 

 at any depth without adjustment or ac- 

 tion by the escapers. During this phase of 

 the escape cycle the HIS supplies air at 1 

 psi more than ambient, first inflating the 

 stole, or lifejacket, built into the suit, 

 and then, through two '/2 psi relief 

 valves, the hood. However fast the pres- 

 sure builds up in the tower the hood 

 remains inflated to provide the escaper 

 with a comfortable air lock from which 

 to fill his lungs. Without thought or ac- 

 tion he gets as much air as he needs and 



only wastes the slight overflow from the 

 open bottom of the hood. 

 When the tower pressure equals that of 

 the sea, the upper hatch opens. Because 

 this is all that has been keeping the 

 escaper in the tower, he starts his ascent 

 and the air connection disengages, both 

 parts sealing automatically as they sepa- 

 rate. Bottom time is under three seconds. 

 The ascent is completed at 8.5 feet per 

 second and the escaper breathes nor- 

 mally all the way. By doing this he 

 ensures that his lungs are at the same 

 pressure as that in the hood and there- 

 fore the sea, because the hood is open at 

 the bottom. 



On arrival at the surface the hood is 

 removed and the suit starts its next task 

 of protecting the escaper from exposure 

 or drowning.^^ 



—Todd (1) 



Now, let us look at the escape procedures 

 for two manned submersibles, BEN FRANK- 

 LIN and STAR III. 



a) BEN FRANKLIN: 



This escape procedure assumes that any 

 escape will involve depths where decompres- 

 sion times will extend beyond the endurance 

 of the Draeger FGG III. This procedure fur- 

 ther assumes that a Personnel Transfer Cap- 

 sule (see the SRC in Chap. 15) will be ready 

 to accept escaping personnel in the immedi- 

 ate vicinity of the after hatch. 



1. Rig hatch skirt. 



2. Make decision on use of life raft. 



3. Turn on all battery powered lan- 

 terns. 



4. Conduct final surface communica- 

 tions. 



5. Place mode switch in zero mode 

 (OFF). 



6. All hands don life vests. 



7. All hands don breathing rigs. 



8. Remove all main power fuses. 



9. Short exterior fuse clips to blow exte- 

 rior fuses. 



10. Undog after hatch. 



11. Flood boat as fast as possible via 

 variable ballast tank inboard vents 

 and SAS vent. Secure flooding when 

 water level is just about skirt lip. All 



661 



