Why a vessel is not a building
A ship is a sealed steel box with a galley, stores, accommodation and a constant flow of goods and people through a small number of openings. Harbourage is behind panelling, in cable runs, in insulation and in the void spaces that exist on every deck, and almost none of it can be opened on a whim. Add movement, vibration, humidity and a crew living in the space, and both the method and the timing change.
The operational constraint is the real difference. A building can be treated tomorrow; a vessel is treated in the window it is alongside, and that window is set by cargo operations rather than by us. Work that is not finished before sailing is not finished at all, so scoping and mobilisation matter more here than on any shore job.

