TM 55-1930-209-14&P-2 Table 3-2.  Seawater System Valves (continued) Figure 1-3 Label Identification Type Callout Location and Valve Function 4-in gate valve SW11 Void 2 starboard - In SEAWATER PUMP 1 SUP- ROWPU membrane clean- PLY: Allows flow from ing supply crossover ROWPU membrane cleaning line supply to seawater pump 1 4-in gate valve SW12 Void 2 starboard - In SEAWATER PUMP 2 SUP- ROWPU membrane clean- PLY: Allows flow from ing supply crossover ROWPU membrane cleaning line supply to seawater pump 2 4-in gate valve SW13 Void 2 starboard - In SEAWATER PUMP SUPPLY ROWPU membrane clean- CROSSOVER: Isolates sea- ing supply crossover water pump 1 supply from line seawater pump 2 supply Valves SW14 and SW15 were eliminated in redesign. 4-in globe valve SW16 Void 2 starboard - In SEAWATER PUMP 1 TO seawater pump 1 SEAWATER FILTER: Allows discharge line seawater to flow from seawater pump 1 to ROWPU's via filter and isolates pump 4-in globe valve SW17 Void 2 starboard - In SEAWATER PUMP 2 TO seawater pump 2 SEAWATER FILTER: Allows discharge line seawater to flow from seawater pump 2 to ROWPU's via filter and isolates pump 4-in globe valve SW18 Void 2 starboard - In OVERBOARD DISCHARGE: ballast tank drain line Allows seawater being on discharge side of drained from ballast tank seawater pumps on star- to be discharged by sea- board shell water pumps directly overboard 4-in gate valve SW19 Void 2 starboard - In SEAWATER PUMP seawater pump discharge DISCHARGE CROSSOVER: crossover line Isolates seawater pump 1 discharge from seawater pump 2 discharge 4-in globe valve SW20 Void 2 starboard - In SEAWATER FILTER 1 IN: seawater pump 1 Allows seawater to flow discharge line from seawater pump 1 to ROWPU 1 via filter and isolates filter 4-in globe valve SW21 Void 2 starboard - In SEAWATER FILTER 2 IN: seawater pump 2 Allows seawater to flow discharge line from seawater pump 2 to ROWPU 2 via filter and isolates filter I 1/2-in throttle valve SW22 Void 2 starboard - In SEAWATER FILTER 1 seawater filter 1 drain DRAIN: Allows removal line of solids from seawater filter 1 1 1/2-in throttle valve SW23 Void 2 starboard - In SEAWATER FILTER 2 seawater filter 2 drain DRAIN: Allows removal line of solids from seawater filter 2 3-7