A grid object is a type of helper object you can create whenever you need a local reference grid or construction plane somewhere other than the home grid.
One grid establishes the pitch of the boat, another the pitch of the ship.
Grids used in a scene to align objects
You can have any number of grid objects in your scene, but only one can be active at a time. When active, a grid object replaces the home grid in all viewports.
You can freely move and rotate grid objects, placing them at any angle in space, or attach them to objects and surfaces. You can also change viewports to display a plan or top view of any active grid object.
Grid objects can be named and saved like other objects, or used once and deleted.