His recognition of this color change as a sign of approaching land, if the accounts are accurate, is precisely the kind of knowledge that a person with a Hainan maritime background and years of merchant sailing experience would possess. Deep-ocean blue means open water; coastal green means the shelf, means land, means the possibility of fishermen.
## Emmermann, U-172, and the Other End of the Story
Carl Emmermann was thirty years old when he torpedoed the Benlomond on November 23, 1942. He was one of the most decorated U-boat commanders of the Second World War — a recipient of the Knight’s Cross with Oak Leaves, awarded for accumulated sinkings — and he would survive the conflict, unlike the majority of his fellow U-boat officers.
The fate of U-172 provides a specific historical context that rounds out the account. The submarine served in three wolf-pack formations — Eisbär, Unverzagt, and Seeräuber — and across its six patrols it accumulated a record of destruction that made it one of the more effective U-boats of the war. It was eventually sunk on December 13, 1943, in an engagement west of the Canary Islands that involved a remarkable combination of assets: aircraft from the escort carrier USS Bogue, the American destroyer USS Badger, and three other destroyers — USS Dupont, USS Clemson, and USS Osmond Ingram. The action lasted approximately twenty-seven hours and involved hundreds of depth charges before U-172 was finally destroyed. Of the crew, thirteen men died; forty-six survived and became prisoners of war.
Carl Emmermann himself survived, was repatriated at the war’s end, and died in 1990 — one year before Poon Lim.