NOAA Charting - Unimak Pass Unimak, Alaska

We conducted two hydrographic surveys in this critical shipping waterway using 100% shallow-water multibeam sonar. Bathymetry was acquired using the hydrographic survey vessel R/V Kittiwake, a steel hull vessel, 30.3 meters in length.

Multibeam confidence checks were conducted to verify proper operation of the multibeam suite regularly throughout the project.

The final depth information was submitted as a collection of CARIS BASE surfaces that best represented the sea floor at the time of the survey. Several grids of varying resolution were created due to the wide depth range and varying bathymetry found in the survey area.

Sounding data was tide adjusted using final tide levels for the historic U.S. Coast & Geodetic Survey (USC&GS) tide station at Cape Sarichef on Unimak Island.

The survey identified a sunken cargo vessel that had never been charted. A review of the Department of the Interior, Minerals Management Service, Alaska Outer Continental Shelf Regions online database, produced an entry suggesting that the wreck was the 551' M/V Pan Nova, a Korean freighter carrying a cargo-load of wheat that sank five nautical miles north of Akun Island on September 10, 1983, following a collision with another Korean freighter in the Unimak Pass area.

Major data collection systems used onboard the Kittiwake for this survey were the following:

• Reson SeaBat 8101 - Multibeam sonar
• Seatex Seapath 200 - Positioning
• Applied Microsystems SV Plus - Sound speed
• Seatex MRU-5 - Vessel attitude

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