Convention: +Y forward / −Y aft, −X port / +X stbd, Z height (+ up). CRP is 0,0,0 — typically vessel CG at deck level.
Units
2 · Sensors
#DescriptionXYZ
Row 1 is normally Vessel CG / CRP at 0 / 0 / 0 (drawn as a crosshair). All other sensors get a red dot with a named callout. Names containing "moonpool", "crane" or "LARS" also anchor the matching deck feature in the drawing.