He devised tactics for the effective use of submarines, making the members and elements of "silent service" key players in the Pacific victory.

Following promotion to rear admiral in May 1942, he arrived in Perth, Western Australia as Commander, Submarines, Southwest Pacific (COMSUBSOWESPAC).

Lockwood also acted as Commander Allied Naval Forces, Western Australia, until July 1942, overseeing the major bases at Fremantle and Exmouth (Codename "Potshot"), amongst others.

Submarine patrols were long voyages and many times the crew finished up on "iron rations" of poor food as their food supplies ran out, so Lockwood made great strides in providing for rest and recuperation (R & R) for his sailors when they returned to port, such as two-week stays at the Royal Hawaiian Hotel, and crates of ice cream and leafy vegetables to greet returning submarine crews.

He oversaw the tests that proved the unreliability of U.S. torpedoes, which at the time were often running too deep or failing to detonate, and prompted the improvements that made them the highly effective weapons they became in 1944 and 1945.

In fighting for better torpedoes, Lockwood had to fight the Mark 14 torpedo and Mark 6 exploder supporter Rear Admiral Ralph Waldo Christie, who had been involved in the development of these weapon systems in the 1920s and 1930s, and who was convinced that their reported problems were caused by poor maintenance and errors on the part of the captain and crew.

"[2] Importantly, Lockwood cleaned out the "dead wood", replacing timid and unproductive submarine skippers with (often) younger and more aggressive officers.

During the early stages of the Pacific War, U.S. skippers were relatively complacent and docile, compared to their German counterparts who understood the "life and death" urgency in the Atlantic.

As a result of Lockwood's initiatives, the "silent service" suddenly began racking up many kills, including key enemy warships.

He is buried at Golden Gate National Cemetery in San Bruno, California, alongside his wife and Admirals Chester Nimitz, Raymond Spruance, and Richmond Kelly Turner, an arrangement made by all of them while living.