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Although the vehicle is in the prototype stage, the Naval Ocean Systems Center, 

 San Diego, has developed a Solid Rocket Booster (SRB) Dewatering System for 

 the National Aeronautics and Space Administration. The system, referred to 

 as a Nozzle Plug (NP) , is designed to dewater expended SRBs jettisoned during 

 space shuttle launches. Briefly, the specifications of the NP are: 



Length : 4.3m (14 ft) 



Diameter (OP) : 0.8m (2.5 ft) min. 



2.1m (7 ft) max. 

 Buoyancy: +120kg (265 lbs) 

 Weight (in air) : 1,497kg (3,300 l±)s) 

 Operating Depth : 53m (175 ft) 

 Speed: 2 knots (4km/hr) horizontal 



2.5 knots (4.6km/hr) vertical 



The SRBs assume a spar (upright) mode when in the water and they require a 

 log (horizontal) mode for towing to port for refurbishment. The NP is launched 

 from a support ship and maneuvered on the surface to the SRB where it dives 

 to inspect the SRB casing using its TV system. The NP operator visually acquires 

 the nozzle opening by the same TV system. The Plug is then positioned beneath 

 the SRB and, at the appropriate time, uses its vertical and horizontal thrusters 

 to drive it up into the Nozzle throat. When the NP has docked, indicator lights 

 on the surface console show that it is seated and locking arms are deployed 

 to hold it in position. Dewater air is activated through the umbilical cable 

 and a pressure differential is attained which forces the water out. As the 

 water leaves the SRB it raises out of the water and, becoming unstable, falls 

 into the log mode. At this point a sealing bag is inflated on the NP to 

 prevent loss of air and return of water. Dewatering continues until the SRB 

 is emptied. The umbilical cables are then disconnected from the ship and both 

 the SRB and NP are towed to port where the NP is removed and refurbishment 

 begun. 



Assistance in recovery of stricken or trapped manned submersibles by U.S. Navy 

 ROVs has occurred on two occasions. The first incident involves the submersible 

 JOHNS ON- SEA- LINK, the second involves the PISCES III. 



In June 1973 the JOHNSON- SEA- LINK (J-S-L) became entangled in the rigging 

 of a scuttled destroyed at 110m (360 ft) depth off the coast of Florida. 

 Divers attempted to free the submersible but strong currents resisted their 

 efforts. A manned submersible was dispatched but equipment malfunctions caused 

 it to abort the dive. Approximately 32 hours after entanglement a Remotely 

 Operated Vehicle (Plate 3.1) developed by the U.S. Naval Ordnance Laboratory 

 to inspect undersea hardware , carried a grapnel hook which it affixed to the 

 J-S-L. A line from the hook to the surface ship pulled the s\±)mersible free 

 of the hulk. 



Another submersible retrieval incident occurred in August 1973 when the 

 submersible PISCES III sank to the bottom at 480m (1,575 ft) depth southwest 

 of Cork, Ireland. The objective in this incident was to attach lift lines 

 to the vehicle to pull it to the surface. Three lift lines were eventually 

 attached to the submersible, two were attached by sister- vehicles and the 

 third by the U.S. Navy's CURV III. 



