From the publisher:

The Command at Sea Referee's Guide is a 34 page compilation of all the charts and tables contained in the 128 page Standard Rulebook. Use of this playing aid greatly assists the flow of play in multiple player games, as all of the data is right at hand, along with references to the appropriate section of the rulebook. This handy guide will aid the referee is running "Blind" and "Semi-blind" games between two or more teams. Included in this book are sections on: Refereeing Blind and Semi-Blind Games, The Fog of War Play Aids.