Cargo spaces to be included in the computation
of net tonnage are enclosed spaces appropriated for the transport
of cargo which is to be discharged from the ship, provided that such
spaces have been included in the computation of gross tonnage. Such
cargo spaces shall be certified by permanent marking with the letters
CC (cargo compartment) to be so positioned that they are readily visible
and not to be less than 100 millimetres (4 inches) in height.