Tullibee measured approximately 312 feet in length and displaced about 1,525 tons while surfaced. It carried ten 21-inch torpedo tubes—six forward and four aft.
Its diesel-electric propulsion system allowed it to travel long distances on the surface, while electric motors powered the submarine underwater using energy stored in batteries.
The submarine also carried a deck gun and antiaircraft weapons.
These features made Gato-class submarines formidable commerce raiders.
Their primary mission was to attack Japanese merchant shipping, troop transports, tankers, and warships. By destroying vessels carrying fuel, ammunition, food, and military equipment, American submarines could weaken Japan's ability to sustain operations across its expanding empire.
This campaign became one of the most consequential naval efforts of the Pacific War.
Japan depended heavily on maritime transportation. Its island garrisons required supplies from distant bases, while its industries needed raw materials brought by sea.
American submarines attacked that network relentlessly.
But the campaign was extraordinarily dangerous.
Submarine crews operated in confined spaces, often far from friendly forces. Mechanical failures, enemy depth charges, aircraft attacks, and navigation errors could prove fatal.
A damaged submarine might sink before its crew could escape.
Even successful attacks carried risks, particularly when torpedoes malfunctioned or enemy escorts quickly responded.
For Tullibee, the most dangerous threat would ultimately come from a weapon carried inside its own hull.
The Long Patrols Before the Disaster
Before its final mission, Tullibee had already completed three war patrols in the Pacific.
Its first patrol began in July 1943 and took it into waters near the Caroline and Mariana Islands.
The submarine encountered Japanese vessels and launched attacks, but early American submarine operations were frequently frustrated by torpedo problems.
Its subsequent patrols brought additional opportunities to engage Japanese shipping.
Like other American submarines, Tullibee operated under conditions that demanded patience and careful judgment. Crews sometimes spent days searching for worthwhile targets, then had only minutes to calculate a firing solution when a convoy appeared.
By early 1944, American submarine tactics and equipment were improving.
The Navy had spent much of the previous year investigating serious deficiencies in its torpedoes.
Nevertheless, the weapons remained complex mechanical devices, and failures could still occur.