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SUBFACTS is a warning service providing information to mariners of planned or known submarine activity. Submarines may operate for the entire period, or part thereof, in each area notified.

Submarines on the surface will act strictly in accordance with the International Regulations for Preventing Collisions at Sea. Submarines at periscope depth will not close to less than 1500 yards from a fishing vessel unless express agreement has been obtained. Submarines on the surface and at periscope depth will maintain a constant radio listening watch on VHF Ch 16.

SUBFACTS covers planned or known activity off the west coast of Scotland and covers dived submarine activity and surfaced submarines with dived areas allocated. The exercise areas referred to in SUBFACTS are contained within this web site.

Owing to the increased number of standard areas that are active for dived submarine operations during Exercise Joint Warrior (JW) the SXAs are grouped into larger NW/JMC SUBFACTS areas during these exercises only. More general details of the SXAs being used for JW are promulgated in a Notice to Fishermen published some weeks prior to each exercise.

A “Fisherman’s Hotline” telephone number 01923 846364 is available on a 24 hour basis and may be used by any Mariner for any queries relating to SUBFACTS/GUNFACTS.

In addition to radio promulgation, SUBFACTS/GUNFACTS are also broadcast on NAVTEX twice daily at 0620 and 1820 UTC.

Coastguard Broadcast Times
Clyde 0810 2010
Belfast 0710 1910
Stornoway 0710 1910

NOTE: Vessels should listen to the Maritime Safety Information announcement on VHF Ch 16 for details of the working channel to be used for the broadcast.

Full details of the Subfacts/Gunfacts scheme can be found in NP 283 (1) Admiralty List of Radio Signals (ALRS) Volume 3(1).