A standard shell expansion plan is organized using a specific coordinate system:
Thickness Markings: Numbers inside or next to a plate boundary indicate thickness (e.g., 15.0 mm). Some plans use color-coding or hatching to denote different grades of high-tensile steel. Digital Transformation in Shell Expansion shell expansion plan pdf
The X-Axis (Length): Usually represented by frame numbers, starting from the Aft Peak (AP) or Forward Peak (FP).The Y-Axis (Girth): Represented by the "girth distance" measured along the surface of the hull from the keel upward toward the sheer strake (the topmost plate). A standard shell expansion plan is organized using
Repair and MaintenanceWhen a vessel undergoes dry-docking for repairs, the shell expansion plan serves as the primary map. If a plate is damaged or thinned by corrosion, the plan allows engineers to identify the exact plate number, its original thickness, and its relationship to internal framing. its original thickness