NOAA ENCŪ

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

US4AK3TC - ALASKA


INDEX:

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


NOTES:

NOTE A
Navigation regulations are published in Chapter 2, U.S. Coast Pilot 9.  Additions or revisions to Chapter 2 are published in the Notice to Mariners. Information concerning the regulations may be obtained at the Office of the Commander, 17th Coast Guard District in Juneau, Alaska, or at the Office of the District Engineer, Corps of Engineers in Anchorage, Alaska.
Refer to charted regulation section numbers.


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 - 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.


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


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


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).


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


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


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.


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


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.


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. 


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/.


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


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