Hints for Semester at Sea

Hints:

1. The top grid consists of ship classes. The leftover letters yield a clue.
2. The bottom grid consists of types of missiles. The leftover letters yield a clue.
3. The puzzle mimics a game of Battleship. The five ship types are represented on the top grid. The ordinance listed in the bottom grid can be used as a filter to obtain the letters that make up the answer. Each letter is conveniently located on a ship of a different class.

There are no more hints for this puzzle.