shell plating. shellplating purpose: –keeps water out –ties together ship’s framework –plays...
TRANSCRIPT
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
Flat Plates
• doesn’t have to be “worked” into shape– therefore, most economical
• because of this…– majority of plates are flat plates
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– 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
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– transverse joints between the plates
• Seams– longitudinal joints between the plates
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
Numbering and Lettering
• Shell Expansion Plan
• notice:– lettering from
keel strake and up
– numbering: from aft forward
aft FWD