HANDLING CHARACTERISTICS 107 



e. Vent interior of Sealab to 15 psi over bottom (bottom of pressure cylinder), thru the air 

 salvage hose by opening valves A-1 and A- 10 and venting thru topside manifold. This will re- 

 lieve excessive pressure inside Sealab. Pressure inside Sealab should be (.445 x 60) plus 



15 = 42 psi gage. 



f. If necessary blow tank No. 2 by opening valve C-2. 



g. Close valve A- 10 



Raise Sealab slowly to 30 ft, always maintaining 15 psi over bottom in Sealab thru umbil- 

 ical air supply. 



Phase 4 



Sealab at 30 ft (to bottom of pressure cylinder) Pneumofathometer reading should be 14 ft 

 (30-16). Internal pressure of Sealab should remain as at 60 ft stop, (42 psi gage) assuming no 

 leaks. No further changes will be made in Sealab pressure or in tanks 1, 2, 3 pressure until 

 Sealab is surfaced. 



Note: At this depth the point of interest will shift from Sealab and ballast tanks 1,2, and 3 to 

 the conning tower. Pressure in Sealab will be kept to at least 15 psi over bottom. At 30-ft 

 depth the top of conning tower hatch will be 11 ft below the surface. The conning tower top 

 hatch has been tested to 15 psi. Therefore 15 psi can be applied to blow out the water and 

 should the top hatch break surface in a swell, the hatch should hold this pressure differential. 



At the 30-ft stop accomplish the following: 



a. Check that bolts on top conning tower hatch are tight. 



b. Have Gear take light strain on No. 3 and 4 lines to keep Sealab clear of staging vessel. 



c. Make overall inspection of Sealab. 



d. Check that bolts on main access hatch are tight. 



e. Adjust air in salvage hose to 15 psi. 



f. Ensure valve C-4 is open. 



g. Open valve A- 8 slowly. 



Maintain not more than 15 psi gage on salvage hose and gradually blow water out of conning 

 tower. As Sealab gets lighter gradually pay out raising wire and raise counterweight to allow 

 Gear to pull Sealab from the staging vessel by gradually increasing pull on lines 3 and 4. 



When conning tower is blown clear keep Sealab about 40 ft from staging vessel. 



Close valve A-8 first and then C-4. Sealab should now float at midpoint of conning tower. 



Phase 5 - Sealab on Surface 



Sealab on surface with conning tower blown. It should have a buoyancy of 6 tons or about 

 13,000 lb. It should float at midpoint of conning tower. 



Maintaining 15 psi over bottom (bottom of pressure vessel) ensure that valves A2, A3, A4, 

 A5, A6, A7, B-1 and B-2 are open. Open valve A-10. 



Open first valve CI and then C3 to blow water out. Caution : Maintain 15 psi over bottom 

 at all times . The compressed air atmosphere must not be reduced at this time by using only 

 the compressed air in Sealab, as this may produce negative pressure on the large access hatch. 



