Lead ship

The lead ship is the first of a series or class of ships all constructed according to the same general design.

Because large ships are complicated internally, and may take a long time to construct, as much as five to 10 years, it is rare to have two of them that are completely identical. It may also be that the second and later ships must be started before the first one is even launched. Nevertheless, it is still more efficient to build copies than prototypes, and so the lead ship will be the one that guides the construction of the others in its class.

From the 20th century to the present, the lead ship usually lends its name to the class, as in Pennsylvania class battleship, whose lead ship was the USS Pennsylvania (BB-38), or more recently Los Angeles class submarine named after the USS Los Angeles (SSN 688). In the latter case, the Los Angeles's hull number "688" is also used informally to refer to the class. The Royal Navy occasionally gives all ships of a class names that have something in common -- perhaps simply all beginning with the same letter -- so that class is known not only by the name of its lead ship, but also by whatever their names have in common. Thus, HMS Zulu was a Tribal-class destroyer even though there was no ship named HMS Tribal, and the Amphion class of submarines are also known as the "A" class.

The United States and Europe have slightly different traditions where concerns class naming: In the United States Navy, a class is always named after the first ship of that class to be approved by Congress - almost (but not quite) without exception the ship of the class with the lowest hull number - while in European navies, a class is named after the first ship in commission, regardless of when that ship was ordered or laid down. In some cases, this has resulted in different class names being recorded in European references from their American counterparts - for example, European references report the Colorado-class battleships of the US Navy as "Maryland-class", since USS Maryland (BB-46) was commissioned over two years before USS Colorado (BB-45).

Russian (and Soviet) ship classes are formally named by the numbered project that designed them. That project sometimes, but not always, had a metaphorical name, and almost always had a NATO reporting name. In addition, the ships of the class would be numbered, and that number prefixed by a letter indicating the role of that type of vessel. For example, Project 641 had no other name, though NATO referred to its members as Foxtrot class submarines. One boat of that class was B-427 -- the "B" standing for bolshaya, meaning "large" -- which also bore the name Scorpion. In contrast, Project 667AM was known in Russia as Navaga, a type of cod, and was given the NATO reporting name "Yankee II. One boat of that class was K-219 -- the "K" standing for kreyserskaya, "cruiser" -- which had no other name.