[Rinaldi]

To: USS S-40, Lt. Cmdr Giovanni Borghia

Conduct combat patrols for a period of no less than 96 hours of Lamon Bay and Southern Luzon Straits, report to higher command as necessary. Engage IJN at your discretion.

Dec. 19th, 1941

• S-40 conducts combat patrol of Lamon Bay, no enemy surface presence - enemy commands the sky. Near miss from Japanese F1 on AS sweep. Daylight movement restricted henceforth.
• Orders are given to divert to Luzon Straits, patrol period shortened to 24 hours.
• Search pattern set 150nm off the coast of Luzon island, submerge every 6 hours for hydrophone sweep.

Dec. 20th, 1941

• Routine hydrophone sweep at 2030 hours picks up sound contact, unidentified, slow screws, crossing
• Surface conditions less than ideal, with moderate swells, but low visibility. Surfacing identifies enemy as merchant marine. S-40 diverts at flank into the night to set up an ambush
• Periscope depth at 2103 hours. General Quarters alarm. Target is crossing, Tubes 1 and 2 opened. Target speed estimated at 4.4knots based on map data.
• 2110-2130 (approx.) Torpedo attack launched, Torpedo 1 runs under, 2 hits amid ships, 3 opened and fired rapidly for hit on the bow. Surface attack initiated, target sunk.
• S-40 breaks contact and reports. With several hours to daylight still to go, Cmdr. Borghia hopes to make up distance to Darwin before the omni-present enemy air power takes to the skies.

To: COMSUBPAC
USS S-40 Status Report; Fuel remaining, 75 percent, Torpedoes remaining, 9. Rebasing at Surabaya via Timor Sea. Will maintain radio silence henceforth.