. "Type IX" . "1944-12-05Z"^^ . . . "All 73 crew killed" . "Submarine sunk" . "''" . "Operational failure" . "British victory" . "U-boat" . . ")" . "Germany" . "(" . "Operation Caesar was a secret mission carried out by Germany in World War II to supply Germany's faltering ally, Japan, with advanced technology to fuel their war machine. The operation was a complete failure.The engagement that ended the mission is the only known instance in history of one submerged submarine sinking another submerged submarine."@en . "U-864" . . "'' (" . "Operation Caesar"@en . . . "HMS Venturer" . "V-class submarine" . .