Destroyers Mikazuki and Ariake of Destroyer Division 30 left Rabaul on July 27th loaded with 500 troops (115th IR and 14th Artillery Regiment), six artillery pieces, five machine guns, and forty tons of other material. Ariake, the newer of the two destroyers, had suffered an engineering casualty and was capable of only 28 knots. However, the destroyers did not travel at this speed because each was towing an MLC. Upon reaching Borgen Bay they further reduced speed. Just before midnight 27/28th July off shore from Tuluvu airfield Mikazuki ran aground. Ariake came alongside, took off personnel and equipment and proceeded to the landing area where they were off-loaded to waiting MLCs. When daylight arrived Ariake had not left the area but was in Borgen Bay standing by to help the grounded destroyer pursuant to orders of the division commander.

On the morning of July 28th fifteen B-25C-1s (designation for a locally modified B-25C with solid nose and mounting eight forward firing guns) headed for New Britain escorted by ten P-38s. Despite the fact that Allied radio intelligence had intercepted a message announcing the departure of the two Japanese destroyers the day before the Americans had no idea such lucrative targets were in Borgen Bay. The formation crossed New Britain from the south and successfully attacked barges and ground targets a few miles farther east. Eight Zeros from 204 Ku under CPO Hideo Watanabe were flying cover for the destroyers at the time. It was the second cover mission of the day directed by the 5th Air Attack Force.

The American attacks had been going for half an hour when an American fighter pilot radioed a warning of enemy fighters. Zeros and P-38s clashed in combats from 9,000 feet down to sea level. The Lightning pilots claimed seven OSCARS destroyed without loss. The Zeros claimed three P-38s and a bomber. Air Group 204 lost the fighter flown by PO 2/C Shigemasa Asami and three others suffered damage. The P-38 pilots were credited with two OSCARS probably destroyed in addition to their seven kills. Capt. James Watson was credited with three of the four victories he claimed. Ace Dick Bong also claimed a victory but returned to base with several machine gun hits in his P-38. Bong’s victory made him the 5th Air Force’s leading ace and he headed for Australia for a well-earned R&R. One of the Japanese pilots in this combat was Petty Officer 2/C Shoichi Sugita, a pilot generally recognized as one of Japan’s leading aces. A month later he was wounded in combat and returned to Japan.

Reading the detailed action reports of American pilots claiming kills on this and other occasions it seems incredible that their verified claims could be at such variance with Japanese reports of losses. Pulled back from the focus of those involved in the immediacy of the action, other perspectives shed a somewhat different light on matters. One of the fighter pilots involved in this combat reported: “I did not get in any shots, nor did I see any aircraft destroyed.” B-25 pilots flying this mission reported seeing a single Japanese fighter fall into the sea. That report is consistent with the Japanese report of the loss of a single Zero.

Japanese troops at Tuluvu got a close look at some of the Zeros covering the destroyers that day. Zeros of 201 Ku landed at Tuluvu including one with engine trouble. This aircraft was badly damaged on landing according to one Japanese account. Tuluvu also got a close look at some less welcome visitors.

Several days before this on July 23d Maj. Paul I. Gunn had flown the first mission in B-25G No. 42-64808 in order to test the aircraft’s 75mm cannon. Col. Donald P. Hall, commanding officer of the 3d Attack Group, had flown as co-pilot. The first mission hit ground targets near Salamaua. A second mission was flown on the 27th against barges near Madang. On the 28th “Pappy” Gunn flew the third test mission. Gunn flew on Col. Hall’s wing as Hall led 14 B-25s to Cape Gloucester on the afternoon of the 28th.

Headed toward Tuluvu that day was a transport plane of the 11th Air Fleet. The Type 96 bomber (G3M) was painted green and sported a twin tail superficially resembling a B-25. This transport was apparently sent to Tuluvu to transport personnel and prepare for a visit by high-ranking Naval officers arriving later.

Although Pappy Gunn was a veteran pilot he grew excited when he saw the transport plane approaching Tuluvu. This was his first chance for an air-to-air kill. Gunn turned his B-25G in for a pass at the transport. In his haste and excitement three 75mm rounds missed. By the time Gunn positioned himself for a second pass the transport was rolling to a stop on the runway. As the B-25s bore in on Tuluvu preparing to bomb and strafe not a gun fired. Some anti-aircraft gunners on the ground thought the airplanes following the transport to be more Japanese airplanes.

The close approach of the B-25s and the report of Pappy Gunn’s cannon finally brought small arm’s fire to life. Pappy Gunn put a 15-pound 75mm round under the transport’s right engine and reported its wing drooped and the wingtip touched the ground. A fire broke out. Gunn estimated 10-15 occupants probably killed. One member of the crew was killed and four wounded.

Pappy Gunn flashed ten feet over the Tuluvu runway chased by a hail of small arms and anti-aircraft fire. Escaping from this he pulled his B-25G into a climb and immediately sighted a destroyer four miles off the coast. Col. Hall led the way with Gunn formed up on his wing. Hall put a 300-pound bomb next to Mikazuki’s hull at the water line while Gunn punched three holes in her with his 75mm gun. The following pilots sighted Ariake in the bay and claimed fourteen bomb hits. The Japanese reported four hits. The result was the same. Ariake blew up and and sank in deep water with heavy loss of life.

Gunn returned to Tuluvu and fired 19 rounds at the anti-aircraft positions that had harassed him. The B-25s took their leave just as seven covering Zeros of the 5th Air Attack Force’s fourth air patrol finally found them and counter-attacked. In the combat that followed one B-25 was shot up so badly it later crashed in New Guinea. The Japanese claimed one bomber certain and another probable. Three Zeros were hit including one that force landed. This was probably the same aircraft reported as landing badly damaged at Tuluvu. The B-25s claimed two of the Japanese fighters destroyed.

That night destroyer Akikaze arrived to strip moveable equipment from Mikazuki and secure her codes and secret documents. Salvage of the flooded Mikazuki in her exposed position was determined to be impracticable and she was given up for lost. Several raids by B-25s and other American planes the following day completed her destruction. Pappy Gunn returned in his B-25G to fire more 75mm rounds into Mikazuki and Tuluvu’s anti-aircraft positions. During one of these raids an escorting P-38 claimed the destruction of a DINAH that stumbled across the action.