ZCZC IA17 240843 UTC OCT BALTIC SEA NAV WARN 031/26 LOW SEA LEVEL THE BELTS: FROM OVERNIGHT INTO SUNDAY TO LATE SUNDAY EVENING APPROXIMATELY -50 TO -60 CM BELOW BALTIC SEA CHART DATUM IN CONNECTION WITH LOW TIDES WESTERN BALTIC: SUNDAY LATE AFTERNOON TO MONDAY AFTERNOON AROUND -60 TO -70 CM BELOW BALTIC SEA CHART DATUM. THEN RISING. NNNN