On March 25, 1915, the submarine USS F-4 slipped beneath the waters off Honolulu, Hawaii, for what was supposed to be a routine training dive. She never came back. When she failed to surface, anxiety quickly turned to dread. The Navy had lost its first submarine at sea with all hands aboard. The disaster was not only a human tragedy, it was also a crisis for a service that was still experimenting with the strange new world of undersea warfare. Submarines were only beginning to find their place in naval strategy, and to lose one so suddenly and completely raised difficult questions about their safety, their reliability, and their future.

The USS Ronquil (SS-396) was a Balao-class submarine, one of the many steel predators the U.S. Navy sent into the Pacific during World War II. She carried the name of a humble spiny-finned fish from the waters of the Pacific Northwest, but her business was far from small. Commissioned on April 22, 1944, under the command of Lieutenant Commander H. S. Monroe, Ronquil’s steel frame stretched over 311 feet, her two propellers driven by the throb of Fairbanks-Morse diesels and Elliott electric motors. She carried ten torpedo tubes and a 5-inch deck gun, but what mattered most was the crew of eighty-one who would have to take her into combat and bring her back again.

July 9, 1944, started out like so many days in the northern Pacific. Cold, fog-draped, and heavy with tension. Aboard the USS Sunfish (SS-281), the crew was already braced for action. They’d spent the previous evening weaving through fog banks, probing northern sea lanes near the Kuriles, hoping to intercept something worthwhile. At 0936, radar picked up three contacts, pips dancing on the screen, about 15,650 yards out and closing. Twenty miles north of Araido To, the hunt had begun.