Longitudinal framing

Longitudinal framing (also called the Isherwood system after British naval architect Sir Joseph Isherwood, who patented it in 1906) is a method of ship construction in which large, widely spaced transverse frames are used in conjunction with light, closely spaced longitudinal members. This method, Isherwood felt, lent a ship much greater longitudinal strength than in ships built in the traditional method, where a series of transverse frames were fit together closely from the keel upwards.