In a continued effort to update charts of the nation’s ports, the NOAA survey ship, Thomas Jefferson, set out on a three-week data-harvesting mission in May near Charleston, North Carolina, and Wilmington, South Carolina.
The first of several survey missions set for 2015, the Thomas Jefferson, and her companion fleet of smaller boats, will run hydrographic operations to collect updated depth and other measurements covering nearly 120 square nautical miles.
“It might surprise people to know that our current chart relies, in part, on surveys conducted just two years after World War II ended,” said Kyle Ward, the navigation manager for the southeast region at the Office of Coast Survey. “In other survey project areas, the data is 45 years old.”
When the area was first mapped in the 1940s, surveyors listened to depth echoes on the world’s first fathometer and hand-recorded their data. Essentially, the fathometer sent pings that echoed off the ocean floor back to an operator wearing headphones. The record of the time it took was recorded on a long strip of paper.
This time the ship, named after the president who ordered the first coastal survey in U.S. history, will use a state-of-the-art side-scan sonar and multibeam echo sounders to pinpoint depth and locate any sunken hazards. The data collected will be used to update raster chart 11528 (Charleston Harbor Entrance) and the accompanying electronic versions.