On Tulagi Island, under Kennedy's supervision and with his help, "PT-59" had all four of her torpedo tubes removed, as well as her two depth charges, and was converted into a more powerful gunboat. She retained two heavy 40-millimeter Bofors cannon anti-aircraft guns now fitted fore and aft. The refit also added six .50-caliber machine gun nests, with three on each side, behind shields. Shielded twin fifty caliber machine guns were placed behind and on each side of the cockpit elevated on circular mounts, and by some accounts, 2 additional thirty caliber machine guns forward of the cockpit in the front of the boat on each side. The higher caliber guns were added to increase range and power and to make the "59" more effective against both Japanese barge traffic, which had powerful guns, and heavy caliber Japanese land and shore based garrisons. Admiral William Halsey, and other high ranking Naval officers, had concluded that the torpedo tubes and Bliss–Leavitt Mark 8 torpedoes assigned the old PT's, were highly unreliable, inaccurate, and the torpedoes very rarely hit their mark against larger craft, particularly Japanese destroyers and cruisers. The new PT gunboat was given slightly higher quality radar, and a taller radar mast that could, in theory, boost reception and transmission to . Kennedy lived on the boat during its refit, and worked extremely hard according to Lieutenant Alvin Cluster, who admitted "I never saw a guy work harder, longer hours". Kennedy's gunboat, sometimes referred to as "PT-0001" was the first completed, and it carefully followed the design and planning of both Kennedy and squadron commander Cluster. Another PT gunboat was given to Lenny Thom, who helped in the refit, and later commanded. Thom had been Kennedy's former executive officer on "PT-109".