Shell Plating

Shellplating purpose: keeps water out ties together ship’s framework plays important part in resisting longitudinal bending stresses needs to be stronger amidships than at the ends particularly at the deck and bottom

Shellplating is… stiffened by frames supported by frames composed mostly of rectangular steel plates arranged longitudinally

Shellplating strake shell plating arranged longitudinally one plate after another a row a course

3 Types of Shell Plating flat plate rolled plate furnaced plate

Flat Plates doesn’t have to be “worked” into shape because of this… therefore, most economical because of this… majority of plates are flat plates

Rolled Plates curvature in only one direction most often found at the turn of the bilge

Furnaced Plates curvature in two direction must be heated and pressed into desired shape by placing heated plate over a form most expensive avoided as much as possible because of expensive

developed by a yard in Germany built entirely of flat surfaces builders of the battleship “Bismarck” built entirely of flat surfaces

Layout of Shell Plates greater Girth mid-ship then at ends Girth: distance around the hull results in excess plating at the ends therefore, certain strakes (rows) are dropped as bow and stern are approached

Drop Strake dropped strake, top strake of the two involved, is called the Drop Strake

Through Strake the other strake, the bottom of the two involved, that runs through in continuous line from stem to stern is called the Through Strake see expansion plan

Stealer Plate The “new” single plate that butts up against the two strakes involved, is called the Stealer Plate it is necessary due to the reduction in girth

Butts and Seams Butts Seams transverse joints between the plates longitudinal joints between the plates

Names and Letters of Strakes

Thickened Plates… certain plates are thickened in areas of higher stress sheer strake keel plates plates on the bottom forward (pounding) bottom and bilge margin plate (provides more substantial material for connection of outboard ends of floors and for the frames, also protect against more rapid corrosion in this area) (deck stringer) outboard most strake on deck

Thickened Flat Plate Keel notice: molded surface in the same plane

Reference pg. 201 Steel Merchant Ships

Numbering and Lettering Shell Expansion Plan notice: lettering from keel strake and up numbering: from aft forward aft FWD

Plan of Deck Plating aft Deck Stringer Strake Stringer Strake outer most strakes on deck Stringer Strake aft