Hull number

The hull number visible on both sides of the bow of USS Arleigh Burke

Hull number is a serial identification number given to a boat or ship. A lower number implies an older vessel. The precise usage varies by country and type.

Civilian use

For civilian craft manufactured in the United States, the hull number is given to the vessel when it is built and forms part of the hull identification number, which uniquely identifies the vessel and must be permanently affixed to the hull in at least two places. A Hull Identification Number (HIN) is a unique set of 12 characters, similar to the Vehicle Identification Number which is found on automobiles. The HIN may be found on the aft of the vessel in the uppermost right corner. Also, the HIN may be stated on the title, registration, and insurance documents.

United States military

The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration employ hull numbers in conjunction with a hull classification symbol to uniquely identify vessels and to aid identification. A particular combination of hull classification and hull number is never reused and therefore provides a means to uniquely identify a particular ship. For example, there have been at least eight vessels named USS Enterprise, but CV-6 uniquely identifies the World War II carrier from all others. For convenience, the combined designation, which is painted on the side of the ship, is frequently called the hull number.

The U.S. Navy sometimes ignores the sequence of hull numbering. For example, the Navy built the last Los Angeles-class submarine as SSN-773; then built SSN-21 through SSN-23; and later resumed the original sequence with SSN-774 for the next class of submarines. This was done because the Seawolfs were to be a radical new design for the endgame of the Cold War, but severe cost overruns combined with the downsizing of the defense budget and the end of the Cold War resulted in only the three boats being constructed.^{[citation needed]} Also, when ships are constructed in American shipyards for foreign nations, any hull numbers used to identify the ships during construction will not be reused by the U.S. Navy; the Perth class destroyers built for the Royal Australian Navy were identified as DDG-25, DDG-26, and DDG-27, but these numbers were not granted to American warships after the Australians changed them to their own identification numbers. When a naval vessel is refitted for use as a different type of ship, a new hull number is sometimes assigned along with its new classification. Often the number remains the same while the hull classification changes.

Hull numbers are also used to identify tanks.

See also

• Pennant number

References

• United States Code of Federal Regulations, Title 33.
• USS Enterprise (CV-6) website
• Hull numbers for surviving Tiger tanks