It is a concept of naval architecture. It distinguishes two parts of the hull.
Living works
The vivid works are those which are located under the waterline (in navy blue on our drawing), below the water level. These are the ones the boat relies on to sail.
Dead works
The dead works concern the whole part of the hull that is out of the water (in orange on our drawing). They create volume in the boat but are not used to navigate the boat (hence the name"dead").
