MMA Machinist's Mate, Non-Nuclear, Submarine Auxiliary

The Machinist’s Mate, Non-Nuclear, Submarine Auxiliary (MMA) is an enlisted rating in the United States Navy. MMAs operate and maintain non-nuclear mechanical systems aboard submarines.

They receive extensive training in the operation and maintenance of: Hydraulic power plants Hoists and cylinders Oxygen generators Atmosphere control equipment Refrigeration systems Emergency diesel engines Pressurized air systems Plumbing systems

MMAs are vital to day-to-day operations. Their responsibilities may include: Operating and maintaining damage control equipment and systems Operating and maintaining internal combustion diesel engines and diesel engine support systems Manufacturing and storing oxygen

MMAs receive hands-on training every day until they are able to walk on their own. They don’t need a lot of prior experience to join the Navy.