NOAA Ship Fairweather zigzags her way to accurate and precise depth soundings

The officers, scientists, and crew of the NOAA Ship Fairweather have started their 30-day Arctic reconnaissance survey, and you can watch their progress on NOAA’s ship tracker website.

The planned route of Fairweather’s reconnaissance survey, August 2012

The diagram on the right shows the corridor Fairweather will travel during this survey project. (Fairweather’s survey corridor is shown in green.) The ship will zigzag back and forth within that corridor, checking actual depth soundings against measurements acquired during the 20th century or even earlier. (See the vintage of the depth measurements in the Aug 1 blog post, Arctic reconnaissance survey checks old soundings to prioritize future surveys.)

By the way, completely surveying the green track line, in a normal full-bottom survey, would take 880 days! So you see why Fairweather commanding officer Cmdr. Jim Crocker is taking the ship on a reconnaissance survey, instead of “mowing the lawn” like survey ships do when they map out sections of the ocean or coastline in a grid pattern.
Taking sample measurements of the water depths during this reconnaissance is vitally important to NOAA’s mandate to provide the maritime industry with accurate and precise nautical charts. Coast Survey hydrographic teams have been measuring ocean depths in coastal Alaskan waters since the 1870s, and many of NOAA’s Alaskan nautical charts ‒ especially in the Arctic ‒ still rely on those depth measurements, many made with lead lines. Additionally, vast swaths of early Arctic measurement locations were based on celestial positioning.
By using modern geospatial technology, with advanced survey technologies, Fairweather will help ensure that both measurements and locations are precise.
The ancient Greek poet Homer said, “It was with a happy heart that the good Odysseus spread his sail to catch the wind and used his seamanship to keep his boat straight with the steering-oar.” We wish the good crew of the Fairweather happy hearts like the heroic Odysseus, but they’ll have to wait to keep their boat straight in future projects.
For this survey, zigzagging is just fine.

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