Subsunk is a text adventure game by Firebird developed by Peter Torrance and Colin Liddle in 1985 for the Amstrad CPC, Commodore 64, and ZX Spectrum home computers
Ed Lines, reporter for the "Seafaring Gazette", is aboard the nuclear submarine Sealion for a routine patrol when the sub is attacked and disabled by a foreign power. The crew are taken into captivity and the sub scuttled - with the hidden journalist still aboard. He must alert headquarters with the news of what has happened and escape the doomed vessel.
The game was produced using The Quill computer program and includes simple graphics. The player must guide Ed Lines in his attempt to escape the stricken submarine; he must reach the telex room and issue the distress signal "SUBSUNK" to alert the authorities and bring assistance. Meanwhile, the wrecked submarine is filling with water...
It was followed by a sequel, Seabase Delta.
Source: Wikipedia, "Subsunk", available under the CC-BY-SA License.