On a vessel's hull, a rib is a lateral structural member which runs between gunwales and sprouts from the keel. They are called "ribs" because they resemble the human rib. The ship's outer planking and inner sheathing are attached to the ribs. For ships that are too large for a rib to be made out of a single piece of wood, the ribs are made of multiple sections called futtocks that are scarfed together. The ancient writers Polybius and Plato held that, since the ribs of a ship were the most important part of the ship's framework, then if the ribs were new, then the ship as a whole was new. Iron was first used in shipbuilding to make the ribs and frames, with wood sheathing attached to them, but this proved inadequate compared to replacing the wood sheathing with iron plates.
___Marine_vessel_q.jpg)
>>>PUT SHARE BUTTONS HERE<<<
Rib (nautical) in the context of Carvel (boat building)
Carvel built or carvel planking is a method of boat building in which hull planks are laid edge to edge and fastened to a robust frame, thereby forming a smooth surface. Traditionally the planks are neither attached to, nor slotted into, each other, having only a caulking sealant between the planks to keep water out. Modern carvel builders may attach the planks to each other with glues and fixings. It is a "frame first" method of hull construction, where the shape is determined by the framework onto which the planks are fixed. This is in contrast to "plank first" or "shell first" methods, where the outer skin of the hull is made and then reinforced by the insertion of timbers that are fitted to that shape. The most common modern "plank first" method is clinker construction; in the classical period "plank first" involved joining the edges of planks with mortise and tenon joints within the thickness of the timbers, superficially giving the smooth-hull appearance of carvel construction, but achieved by entirely different means.
Compared to clinker-built hulls, carvel construction allowed larger ships to be built. This is because the fastenings of a clinker hull took all the hogging and sagging forces imposed by the ship moving through large waves. In carvel construction, these forces are also taken by the edge-to-edge contact of the hull planks.