Lofting
Lofting is the process of taking the fair lines of a ship design and developing from them the exact shapes of every plate, frame and structural part, so they can be cut, bent and assembled to fit. Traditionally it was done full-size on the floor of a mould loft, marking out the lines at full scale.
Today lofting is done in the CAD/CAM system: the fair hull surface is used to generate flat plate developments and part shapes, which drive numerically controlled cutting and forming machines directly. Accurate lofting is what makes the blocks fit together on the building dock.
Lofting is where a fair design becomes buildable parts. Errors here multiply downstream as misaligned structure and rework at erection, so accurate lofting — now CAD-driven — is fundamental to the dimensional control that lets modern block construction go together quickly.
What is a mould loft?
A large clear floor space where, traditionally, the ship lines were drawn out full-size and templates made for the structural parts. The task is now largely done in CAD, but the term survives.