Under its instructions, a submarine unable to communicate could proceed to Midway rather than Majuro.
On May 6, Midway was alerted to watch for the missing vessel.
The submarine never appeared.
On May 15, 1944, the Navy officially presumed Tullibee lost.
At the time, the precise circumstances remained unknown.
This uncertainty was common in submarine warfare.
A submarine operating independently might disappear without transmitting a final distress signal. If it sank in deep water, there might be no wreckage or survivors to establish what had happened.
Some American submarines were destroyed by mines.
Others were sunk by Japanese warships or aircraft.
Still others disappeared under circumstances that could never be conclusively explained.
Tullibee initially belonged to that category.
The Navy removed the submarine from the Naval Vessel Register on July 29, 1944.
The men aboard were mourned as lost at sea.
Only after Japan's surrender would the full story begin to emerge.
The Survivor Returned With an Extraordinary Explanation
Japan announced its surrender in August 1945, bringing the Pacific War toward its formal conclusion.
On September 4, 1945, Clifford Kuykendall was liberated from captivity.
After approximately seventeen months as a prisoner, he was finally able to tell American authorities what had happened to Tullibee.
His testimony supplied the missing sequence.
The submarine had reached its patrol area.
It had encountered a Japanese convoy.
Its crew had maneuvered through poor weather and enemy depth-charge attacks.
Two torpedoes had been fired.
Then a massive explosion had destroyed the submarine.
Kuykendall's account gave investigators a compelling explanation for the loss.
The submarine had apparently been struck by one of its own torpedoes.
The timing was crucial.
The explosion occurred almost immediately after the weapons were launched, consistent with the possibility of a circular run.
Kuykendall had also been familiar with the positions of the Japanese escort vessels, making him doubtful that an enemy attack had caused the disaster.
His account could not provide every technical detail.
He had been thrown overboard by the explosion and could not observe what happened inside the submarine.