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Thelead ship,name ship, orclass leader is the first of a series orclass ofships that are all constructed according to the samegeneral design. The term is applicable tonaval ships and large civilian vessels.[1][2][3][4]
Large ships are very complex and may take five to ten years to build. Improvements based on experience with building and operating the lead ship are likely to be incorporated into the design or construction of later ships in the class, so it is rare to have vessels that are identical.
The second and later ships are often started before the first one is completed, launched and tested. Nevertheless, building copies is still more efficient and cost effective than buildingprototypes, and the lead ship will usually be followed by copies with some improvements rather than radically different versions. The improvements will sometimes beretrofitted to the lead ship. Occasionally, the lead ship will be launched and commissioned forshakedown testing before following ships are completed, making the lead ship a combination of template and prototype, rather than expending resources on a prototype that will never see actual use.
Ship classes are typically named in one of two ways; echoing the name of the lead ship, such as thePennsylvania-classbattleships, whose lead ship wasUSS Pennsylvania,[4] and theOlympic class, whose lead ship wasRMS Olympic, or defining a theme by which vessels in the class are named, as in theRoyal Navy'sTribal-classfrigates, named after tribes of the world, such asHMS Mohawk. If a ship class is produced for another navy, the first active unit will become the lead ship for that navy; for example, theOliver Hazard Perry-class frigates are known as theAdelaide class inRoyal Australian Navy service.