to 850 feet. In theory, the chamber is oper- 

 ated as follows: A stricken submarine re- 

 leases a buoy to the surface which is at- 

 tached to a ■'/s-inch-diameter wire. The ASR 

 establishes a four-point moor over the sub- 

 marine and brings the buoy aboard where it 

 cuts it off and attaches the wire to a reel on 

 the base of the SRC. The chamber is then 

 lowered into the water and its two operators 

 reel the positively buoyant chamber down to 

 the submarine where a hemispherical skirt 

 on the bottom of the chamber mates with a 

 compatible surface surrounding the subma- 

 rine's hatch. At this stage the operators blow 

 water out of the mating skirt and, to bring 

 pressure in the mating skirt down to atmos- 

 pheric, the interior of the skirt is vented to 

 the surface. Two separate air hoses lead 

 from the ASR to the chamber: One hose is 

 used solely to vent the skirt and the second 

 hose supplies air to power the downhaul reel, 

 provide breathing gas and blow out the mat- 

 ing skirt. Although those functions are con- 

 trolled by the personnel within the chamber, 

 they must rely on the surface for high pres- 

 sure air. With the interior of the skirt dry 

 and at atmospheric pressure, the hatch in 

 the bottom of the hull and the hatch on the 

 submarine can now be opened for ingress of 

 trapped personnel. In addition to the two 

 operators, six rescuees are routinely accom- 

 modated, but in an emergency far more may 

 squeeze into the 7-foot ID, 7-foot-high cylin- 

 der. To ascend, the hatches are shut, seawa- 

 ter is readmitted to the skirt to break the 

 pressure differential and it unreels its way 

 to the surface. Where depth allows, a diver 

 can attach a suitable cable to the hatch to 

 perform the same function. Similar to the 

 DSRV, the SRC requires a flat, steel base at 

 least 4 feet 7 inches across and suitably 

 machined to effect a watertight seal. In addi- 

 tion, the submarine's hatch cover must have 

 a point on it to which the downhaul cable can 

 be attached. 



Both the DSRVs and the SRC can accom- 

 modate hatches up to 28 inches in diameter 

 which will allow them to open 80 degrees. In 

 order to accommodate either the DSRV or 

 the SRC, a submersible must meet the re- 

 quirements listed below. 



1) DSRV Requirements: The dimensions of 

 the DSRV skirt are shown in Figure 15.6. 



Since the submarine's hatch must open up- 

 ward into the skirt cavity while mated, its 

 dimensions are critical. 



The skirt rests on the rescue seat, which is 

 a reinforced circular steel area surrounding 

 the escape hatch. The rescue seat must have 

 a minimum outer diameter of 65 inches and a 

 maximum inner diameter of 44.5 inches. Ad- 

 ditionally, the area beyond the rescue seat 

 must be in the same plane as the rescue seat 

 and clear of obstructions and projections out 

 to a diameter of 89 inches to accommodate 

 the DSRV shock mitigation ring. The 

 strength required of the rescue seat is de- 

 pendent upon the depth of the rescue opera- 

 tion. Figure 15.4 describes the loads applied 

 to the stricken submarine. 



The skirt mating flange contains a rubber 

 gasket designed to seal rescue seat irregular- 

 ities up to 0.150 inch. The surface of the 

 rescue seat must thus be flat within 0.150 

 inch at all rescue depths and under the loads 

 imparted by the DSRV. 



DSRV HATCH OPEN 



NO PART OF THE DISABLED 

 SUBMARINES HATCH CAN 

 INFRINGE ON THIS SPACE 

 ENVELOPE. 



Fig, 15-6 DSRV skirl (bottom) and SRC lower cfiamber (top) dimensions. 



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