Countermeasure ships employed by the U.S. NAVY in early years and today.

Designators and description
ACM      Auxiliary Minelayer
AM         Minesweeper (WW-II built ----steel hull)
AM         Minesweeper (Post war---wooden hull)
AMC       Coastal Minesweeper
AMCM   Airborn Mine Countermeasures
AMCU    Minehunter
AMH       Minesweeper  Habor
AMS        Motor Minesweeper (WW-II built ex-yms)
AMS        Motor Minesweeper (Post war wooden hull)
CM          Minelayer  Cruiser
CMC       Coastal Minelayer
DM          Minelayer Destroyer
DMS        Minesweeper Destroyer
MCM       Mine countermeasure
MCS         Mine warfare Command and Support Ship Countermeasure
MHA        Minelayer Auxiliary
MHC        Minehunter Coastal
MM          Minelayer Fleet
MMA       Minelayer Auxiliary
MMC       Minelayer Coastal
MMD       Minelayer Fast
MMF        Minelayer Fleet
MSA         Minesweeper Auxiliary
MSB         Minesweeping Boat
MSC         Coastal Minesweeper
MSD         Minesweeper Drone
MSF          Minesweeper Fleet
MSI           Minesweeper Inshore
MSL          Minesweeper Launch
MSM        Minesweeper River
MSO         Minesweeper Ocean
MSR         Minesweeper Patrol
MSS          Minesweeper Special
SM            Minelayer Submarine
YMP         Motor Mineplanter
YMS         Motor Minesweeper (Yard Minesweeper)