NOAA ENCŪ

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

US3AK1DK - UNIMAK PASS, AK


INDEX:

NOTE A
AIDS TO NAVIGATION
POLLUTION REPORTS
CAUTION - USE OF RADIO SIGNALS (LIMITATIONS)
SUPPLEMENTAL INFORMATION
CAUTION - TEMPORARY CHANGES
WARNING - PRUDENT MARINER
ADDITIONAL INFORMATION
AUTHORITIES
CAUTION - HEAVY TIDES
CAUTION - QUALITY OF BATHYMETRIC DATA
CAUTION - SIGNIFICANT CHANGES
CAUTION - SUBMARINE PIPELINES AND CABLES
COLREGS, 80.1705
HORIZONTAL DATUM
RADAR REFLECTORS
WATER LEVELS, CURRENTS, AND TIDES
COMMENTS REQUESTED


NOTES:

NOTE A
Navigation regulations are published in Chapter 2 of each regional U.S. Coast Pilot. Additions or revisions to Chapter 2 are published in the Notice to Mariners. Information concerning the regulations may be obtained from the Coast Guard District Commander. 
Refer to charted regulation section numbers.


AIDS TO NAVIGATION
Consult U.S. Coast Guard Light List for supplemental information concerning aids to navigation.


POLLUTION REPORTS
Report all spills of oil and hazardous substances to the National Response Center via 1-800-424-8802 (toll free), or to the nearest U.S. Coast Guard facility if telephone communication is impossible (33 CFR 153).


CAUTION - USE OF RADIO SIGNALS (LIMITATIONS)
Limitations on the use of radio signals as aids to marine navigation can be found in the U.S. Coast Guard Light Lists and National Geospatial-Intelligence Agency Publication 117. Radio direction-finder bearings to commercial broadcasting stations are subject to error and should be used with caution.


SUPPLEMENTAL INFORMATION
Consult U.S. Coast Pilot 9 for important supplemental information.


CAUTION - TEMPORARY CHANGES
Temporary changes or defects in aids to navigation are not indicated. See Local Notice to Mariners.


WARNING - PRUDENT MARINER
The prudent mariner will not rely solely on any single aid to navigation, particularly on floating aids. See U.S. Coast Guard Light List and U.S. Coast Pilot for details.


ADDITIONAL INFORMATION
Additional information can be obtained at www.nauticalcharts.noaa.gov.


AUTHORITIES
Hydrography and topography by the National Ocean Service, Coast Survey, with additional data from the Corps of engineers, Geological Survey, and the U.S. Coast Guard.


CAUTION - HEAVY TIDES
Extremely heavy tide rips and strong currents which at times make control of a vessel difficult may be encountered in the passages between the North Pacific Ocean and the Bering Sea.


CAUTION - QUALITY OF BATHYMETRIC DATA
The areas represented by the object M_QUAL (Quality of data) are approximate due to generalizing for clarity. Caution is advised, particularly for nearshore navigation or voyage planning. M_QUAL represents areas of uniform quality of bathymetric data. The CATZOC (Category of zone of confidence in data) attribute of M_QUAL provides an assessment of the overall zone of confidence.


CAUTION - SIGNIFICANT CHANGES
Significant changes in depths and shoreline may have occurred in this area of the chart as a result of the earthquake of March 27, 1964. Tidal observations since the earthquake indicate bottom up-lift of +0.3 feet / +0.09 meters in King Cove. Mariners are urged to use extreme caution when navigating in the area of this chart as the magnitude of change except at this site is not known.


CAUTION - SUBMARINE PIPELINES AND CABLES
Additional uncharted submarine pipelines and submarine cables may exist within the area of this chart. Not all submarine pipelines and sub-marine cables are required to be buried, and those that were originally buried may have become exposed. Mariners should use extreme caution when operating vessels in depths of water comparable to their draft in areas where pipelines and cables may exist, and when anchoring, dragging or trawling. Covered wells may be marked by lighted or unlighted buoys.


COLREGS, 80.1705
International Regulations for Preventing Collisions of Sea, 1972. The entire area falls seaward of the COLREGS Demarcation Line.


HORIZONTAL DATUM
The NOAA ENC references the World Geodetic System of 1984 (WGS-84). For charting purposes, the horizontal control of the current realization of WGS-84 is functionally equivalent to the international Terrestrial Reference Frame 2020 (ITRF2020) at the meter level for charts at scales of 1:5,000 or smaller.


RADAR REFLECTORS
Radar reflectors have been placed on many floating aids to navigation. Individual radar reflector identification on these aids has been omitted.


WATER LEVELS, CURRENTS, AND TIDES
Real-time water levels, tide predictions, and tidal current predictions are available on the internet from NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) at https://tidesandcurrents.noaa.gov/water_level_info.html and https://tidesandcurrents.noaa.gov/currents_info.html.


COMMENTS REQUESTED
NOAA encourages users to submit inquiries, discrepancies, or comments about this chart via NOAA's ASSIST tool at https://www.nauticalcharts.noaa.gov/customer-service/assist/.


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