Frame
A Frame is a transverse structural member — a rib — that runs from the keel up the side of the hull to the deck, defining the shape of the hull and supporting the shell plating. The frames together with the keel, floors and beams form the transverse skeleton of the ship.
Modern ships use transverse framing, longitudinal framing or a combination chosen for the ship type and size. The regular spacing of frames — the frame spacing — is a basic dimension used to locate structure and damage along the length of the ship.
Frames carry the loads from the shell plating into the ship structure and hold the hull to its designed shape. Their size and spacing are set by class rules as part of the scantlings; buckled or wasted frames are a structural defect surveyors look for closely, especially in cargo holds and tanks.
What is the difference between transverse and longitudinal framing?
Transverse framing runs ribs across the ship at close spacing; longitudinal framing runs members fore-and-aft with widely spaced transverse web frames. Large ships often use longitudinal framing for better resistance to bending.