NOAA ENCŪ NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION US4AK5XM - SEMIDI ISLANDS AND VICINITY INDEX: NOTE A AUTHORITIES AIDS TO NAVIGATION WARNING - PRUDENT MARINER POLLUTION REPORTS CAUTION - USE OF RADIO SIGNALS (LIMITATIONS) SUPPLEMENTAL INFORMATION WARNING - THE HYDROGRAPHY CAUTION - TEMPORARY CHANGES CAUTION - SUBMARINE PIPELINES AND CABLES RADAR REFLECTORS NOAA WEATHER RADIO BROADCASTS COLREGS, 80.1705 WATER LEVELS, CURRENTS, AND TIDES 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. AUTHORITIES Hydrography and topography by the National Ocean Service, Coast Survey, with additional data from the Geological Survey. AIDS TO NAVIGATION Consult U.S. Coast Guard Light List for supplemental information concerning aids to navigation. 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. 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. WARNING - THE HYDROGRAPHY The hydrography is of varying degress of quality. Charted depths were obtained from smaller scale charts in the areas of sparse soundings and were acquired by vassels in transit. Undetected dangers could exist in those areas. Navigators should exercise extreme caution and report discrepancies or hazards at https://nauticalcharts.noaa.gov. Depths in the areas of denser sounding patterns were acquired by modern survey methods. CAUTION - TEMPORARY CHANGES Temporary changes or defects in aids to navigation are not indicated. See Local Notice to Mariners. 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. 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. NOAA WEATHER RADIO BROADCASTS The NOAA Weather Radio station listed below provides continuous weather broadcasts. The reception range is typically 20 to 40 nautical miles from the antenna site, but can be as much as 100 nautical miles for stations at high elevations. Sitkinak Dome, AK WNG-718 162.450 MHz COLREGS, 80.1705 International Regulations for Preventing Collisions at Sea, 1972. The entire area of this chart falls seaward of the COLREGS Demarcation Line. 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/. ADDITIONAL INFORMATION Additional information can be obtained at www.nauticalcharts.noaa.gov. END OF FILE