In March 1944, Tullibee departed Pearl Harbor for its fourth war patrol.
Lieutenant Commander Charles F. Brindupke was in command.
The submarine was assigned to operate near the Palau Islands, an important Japanese military and transportation center.
Palau's location made it strategically valuable.
Situated east of the Philippines, the island group served as a staging and support area for Japanese naval forces and merchant shipping moving between different parts of the western Pacific.
For an American submarine hunting enemy traffic, these waters offered opportunities.
They also brought significant danger.
Japanese convoys frequently traveled with escorts, and enemy forces maintained aircraft, patrol vessels, and coastal defenses throughout the region.
Tullibee entered those waters knowing that any attack could quickly become a fight for survival.
A Japanese Convoy Appeared in the Darkness
On March 25, 1944, Tullibee reached its assigned patrol area north of Palau.
The submarine was operating in support of planned American carrier strikes against Japanese installations in the region.
Those strikes, scheduled for March 30 and 31, were intended to damage Japanese ships, aircraft, and facilities before they could interfere with Allied operations elsewhere in the Pacific.
Submarines positioned near the islands could intercept vessels attempting to enter or leave the threatened area.
On the following night, Tullibee detected a Japanese convoy by radar.
According to Kuykendall's later testimony, the convoy included a large transport, two medium-sized freighters, and several escorts, including a destroyer.
The American submarine began maneuvering toward the larger transport.
Conditions were poor.
Rain squalls reduced visibility, and the darkness made it difficult to identify targets accurately.
The crew could calculate the convoy's approximate speed and course using radar, but a successful torpedo attack still required an accurate firing solution.
Brindupke attempted several approaches.
Each time, visibility and the movements of Japanese escorts complicated the attack.
The Japanese vessels were aware that a submarine might be nearby.
During the encounter, the escorts reportedly dropped between 15 and 20 depth charges.
A depth charge was an explosive weapon designed to detonate underwater near a submarine. Even without a direct hit, the pressure from an explosion could damage machinery, rupture pipes, or compromise the pressure hull.