Between 8 October and 8 December they worked to install anti-torpedo nets across the entrance to Mariveles Bay. Continuing on after losing what little remained of their equipment during the Japanese air raid on Cavite on 10 December, they kept up the work, completing 95% of the job by 14 December when they were ordered to cease operations. On 17 and 18 December, they moved two unsunk sections of the net to Manila, and then, on 19 December, reported for duty under Commander, Inshore Patrol, 16th Naval District. From that time until 9 April 1942, "Napa", operating from Mariveles, performed various duties which included net tending, salvage, towing and patrol assignments in the Bataan Manila Bay area. Having re-equipped the gun deck with a 50-caliber Lewis machine gun mounted between the two 3-inch guns, the "Napa" was intermittently involved in direct enemy combat and, according to Chief Petty Office William "Gunner" Wells (Retired Commander), had ten confirmed kills and four probables to its credit.