Nuclear-powered attack submarines (SSNs) are capable of operating in shallow, confined waters-but the smaller, quieter, more maneuverable antisubmarine subs (SSKs) are better suited for operations in such waters. The U.S. Navy should acquire a relatively small number of SSKs for operations in the littorals. SSNs, which can conduct long-range operations submerged and at high sustained speed, should be used primarily in deep water.

The Littoral Operating Environment

The characteristics of the physical environment and weather/climate considerably affect the employment of surface ships and submarines. An ocean's open, deep water poses different challenges than areas close to the landmass, or littorals. (The strict definition of "littoral" refers to a coastline of land and near-shore waters, particularly the area between extreme high and low tides. More broadly, the term designates a coastal region.)