OUTBOARD SECTION 

 RETRACTS UNTIL 

 FLUSH WITH HULL 



CRADLE 

 FOR SUB 



HEAVY SPROCKET CHAIN 



ARCH MAINTAINS 

 VERTICAL POSITION 

 AS UNIT LIFTS 



FLOATS 



PNEUMATIC FENDERS 

 REQUIRED IN 

 SUB DOCK SPACE 



Fig. 12,18 Drawbridge concept (A.P. lanuzzi, Westinghouse} 



Fig. 12.19 Stiff leg boom. 



609 



