Argosy 2325

The story from the Readme file:

In February of the year 2172 the Earth was rocked by massive explosions resulting from a series of meteor impacts. As had been long predicted, a "nuclear winter" resulted. What had not been predicted was the development of vast, unrelenting, and monstrous storms which swept the face of the planet with winds at greater than two hundred miles per hour. The few people that survived what became known as the "cataclysm" found themselves isolated, primarily in underground shelters.

The surface of the Earth was covered in drifts of snow hundreds of feet high and a gradually deepening layer of ice. There was, however, one avenue of transportation available - under the sea. So mankind moved to the ocean, finding a home in the shallow areas beneath the covering ice and above the crushing depths. Cities were built at the shoreline, or onto sea mounts, or in rock beneath the water, or in the ice itself.

In the year 2325 the peoples of the Atlantic Ocean are politically divided along the geographic lines of north and south. In the north there is the NAU, or North Atlantic Union, while the south is occupied by independent cities and installations. The expansion of the southern polar cap to the edges of the South American and African continents has isolated the Atlantic from the other oceans, though passage is thought to occasionally be possible.

There have been no major conflicts in the century and a half since the cataclysm. However, piracy is an ever present problem, especially given the availability of an entire ocean into which would be pirates may disappear. And the sea itself is a constant threat to communities and travelers. Charged with maintaining the security of the sea lanes and performing safety and rescue operations is the NAU Guard.