tidealmanac
No predictions loaded for 1991. This site serves NOAA predictions from its own store, and this period has not been fetched for Koyuk, Koyuk Inlet yet. Nothing is estimated or interpolated in its place. NOAA's own page for the station has the official table: tidesandcurrents.noaa.gov.

tidealmanac.site/us/ak/koyuk-koyuk-inlet-9469031/1991

Koyuk, Koyuk Inlet, AK tide table 1991 (printable) · Tide Almanac