The DEEP DRILLER is loaded as shown in Sample Load Form #4. While the unit is deballasting, port valve 5 fails in the closed position. You may deballast from tank 2P by pumping from tank 9P by also opening valves 6 and __________.

Correct Answer: Option C — 20

On the DEEP DRILLER ballast system manifold, bypassing a failed port valve 5 to deballast tank 2P via tank 9P requires establishing an alternative cross-over flow path. Opening valves 6 and 20 redirects the ballast flow through the port cross-connection line, bypassing the blocked valve.