ZCZC FA47 210917 UTC JUL ESTONIAN NAV WARN 112/2026 GULF OF FINLAND. 23-24 JUL 07:00 - 12:00 UTC DAILY DIVING WORKS IN POSITION 59-46.48N 024-50.55E. SAFETY ZONE RADIUS 0.27 NM. STANDING BY VHF CH 16 AND 61. CANCEL 241200 UTC JUL. NNNN