The charge paid to a ship owner for the unused part of a ship is known as

In shipping, a charterer who hires a ship agrees to pay for the space on board, and problems can arise either when the charterer fails to provide enough cargo to fill that space, or when the ship is delayed at port beyond the agreed loading or unloading time.

When a charterer does not supply enough cargo to fill the space they hired on a ship, they must still pay the ship owner for the unused space, and this charge is called dead freight. It compensates the ship owner for revenue lost because part of the ship's capacity was booked but left empty.

Demurrage is charged when a ship is kept waiting at port beyond the agreed time, which is a delay charge rather than a charge for unused cargo space. Dock dues are fees paid for using port facilities, and a penalty is a general term for a punitive charge, neither of which specifically describes payment for unused ship space.

Distinguish the two shipping charges this way: dead freight is for space booked but not filled with cargo, while demurrage is for time lost through delay at port.