This is the highest ranking enlisted member of the crew, almost always a Master Chief Petty Officer, E9. He reports directly to the captain on matters regarding the crew. He/She will also be called upon to judge to readiness of the crew in times of stress and battle. On smaller ships a Senior Chief Petty Officer, E8, might fill this space. On a submarine they are know as Chief of the Boat, COB.

The ranks Fleet Master Chief Petty Officer and Force Master Chief Petty Officer are used for larger commands such as U.S. Fleet Forces Command, U.S. Pacific Fleet, Submarine Force U.S. Atlantic Fleet, and Naval Air Force U.S. Pacific Fleet. Then there is the Master Chief Petty Officer of the Navy.
The CMC is will make rounds all over the ship to ensure the crew is doing as they should. If he sees a sailor who needs a shave he will tell them. If he sees a sailor who needs to fix his uniform he will tell them. If he finds anything that is out of place he will find out who should be taking care of it and get things fixed. If you think for one moment you can pull one over on the CMC, you are wrong!

These sailors have been around the black so many times they block asks them for directions. They are all rumored to have been seamen recruits on the Ark with Noah. Some of them stood fire watch when the sun was lit off. The CMC we had on the Scott had been in Vietnam as an enlisted captain, he commanded a river boat. He had twice as many medals as our Captain. He was a crust old sailor whom you had to earn his respect, but he stood behind the enlisted crew with all he had.

One day a fellow engineer had forgotten to shave and Master Chief caught him. The sailor tried to use the water hours excuse for not shaving. Master Chief asked him to follow him. He took him into the goat locker and handed the engineer his personal electric shaver. All he told him was clean up before you leave.