Hull Classification Symbol - National Oceanic and Atmospheric Administration

National Oceanic and Atmospheric Administration

The National Oceanic and Atmospheric Administration (NOAA), a component of the United States Department of Commerce, also uses a hull classification symbol system, which it also calls "hull numbers," for its fleet. In its system, the NOAA fleet is divided into two broad categories, research ships and survey ships. The research ships, which include oceanographic and fisheries research vessels, are given hull numbers beginning with "R", while the survey ships, generally hydrographic survey vessels, receive hull numbers beginning with "S". The letter is followed by a three-digit number; the first digit indicates the NOAA "class" (i.e., size) of the vessel, which NOAA assigns based on the ship's gross tonnage and horsepower, while the next two digits combine with the first digit to create a unique three-digit identifying number for the ship.

Generally, each NOAA hull number is written with a space between the letter and the three-digit number, as in, for example, NOAAS Nancy Foster (R 352) or NOAAS Thomas Jefferson (S 222).

Once an older NOAA ship leaves service, a newer one can be given the same hull number; for example, "S 222" was assigned to NOAAS Mount Mitchell (S 222), then assigned to NOAAS Thomas Jefferson (S 222), which entered NOAA service after Mount Mitchell was stricken.