5.137A in the Radio Frequency Table Allocation of Ireland.

Content Type
ITU FOOTNOTE
Title
5.137A
Description
The frequencies 6 337.5 kHz, 8 443 kHz, 12 663.5 kHz, 16 909.5 kHz and 22 450.5 kHz
are the regional frequencies for the transmission of maritime safety information (MSI) by means of the NAVDAT system (see Appendices 15 and 17). (WRC-23)