The USS Jimmy Carter, third and last of the Seawolf class of advanced nuclear submarines, will have an extra section inserted into its hull, making it longer than its sister ships. The section will include bunks for 50 SEAL commandos, a five-foot airlock which could be used to deploy SEALS or minesweeping robots, and an auxiliary maneuvering thruster. The first two Seawolfs have such a thruster under the stern; the Jimmy Carter will have a second one under the bow. These thrusters retract into the hull when not in use. They can rotate through 360, allowing them to be used to maneuver in close quarters or dock more efficiently. Because of its longer hull, the Jimmy Carter will have a top speed about 1 knot slower than its sisters. The top speed of the Seawolf class is highly classified; the Navy will say only "more than 30 knots".--Stephen V Cole