Radios used on craft associated with a parent ship, such as launches, tenders, towed vessels, etc., are licensed under the parent vessel’s ship station license. Consequently, DSC-equipped radios on these craft may use the same MMSI as assigned to the parent craft. However, AIS equipment installed on these craft must have a unique identity separate from the parent ship. DSC equipment on these craft may need a unique identity as well. While the ITU has established a special identity for craft associated with a parent ship, the U.S. has adopted a different approach.
MMSIs for Craft Associated with a Parent Ship registered in the United States
Since radio equipment on craft associated with a parent ship are licensed by rule under the parent ship’s FCC ship station license, users may obtain a unique ship station MMSI using the same procedures as MMSIs for Recreational Vessels.
AIS stations used on such vessels using ship station MMSIs should enter “A” followed by the last 6 digits of the MMSI of the parent vessel onto their AIS Call Sign parameter in lieu of an official call-sign.
What to do when Selling or Disposing of your Radio or Radio-equipped Vessel
MMSIs for craft associated with a parent ship registered outside the United States
The ITU has designated the format 9182M3I4D5X6X7X8X9 for craft associated with a parent ship, where the digits 3, 4, and 5 represent the Maritime Identification Digits (MID) and X is any digit from 0 to 9. Most maritime countries have adopted this format. However, no provision currently exists for assigning these identities in the United States.