Pictured here are S-36 (SS-141), S-37 (SS-142), S-39 (SS-144), S-41 (SS-146), and an unidentified boat of SUBDIV 17 alongside USS Canopus (AS-9) at Tsingtao, China, circa 1930. All commissioned in the early 1920s, the San Francisco-built S-boats of SUBDIV 17 came to the Philippines in 1924 and stayed until driven out by the Japanese at the beginning of World War II. The prominent deck guns are 4-inch/50 caliber.