Notice is hereby given that the public Decca Navigator System in the United Kingdom will cease to be provided by the General Lighthouse Authorities (The Corporation of Trinity House, Northern Lighthouse Board and the Commissioners of Irish Lights) on 31st March 2000 in accordance with the General Lighthouse Authorities' Marine Navigation Plan for the period to 2015. The following Decca Chains which provide coverage around the coasts of Ireland will be among those affected:

Chain 1B-SW British	South and South East Coasts of Ireland
Chain 3B-North British	Irish Sea
Chain 8E-Hebridean	North and North West Coasts of Ireland

The Irish Chain 7D, which is operated by an Bord Iascaigh Mhara to provide coverage of the West and South Coasts of Ireland, may continue to broadcast for a further period of time.
Mariners are advised that the sole operation of the 7D Irish Decca Chain will significantly affect the navigational coverage of the Irish Coast as previously provided. The current enhancement of cross chain fixing will be permanently removed. Thus, areas which are on the periphery of the 7D Chain coverage will experience a significant deterioration of fix reliability and accuracy.
Further details will be issued as a correction to Volume 2 of the Admiralty List of Radio Signals.