Hull Filler is a job description for two different types of CARGO used in ships. CARGO is goods or materials that are transported, usually by sea, and is typically used to refer to freight. BALLAST is a material, such as sand, gravel, or water, that is placed in the hull of a ship to provide stability and balance. Both CARGO and BALLAST are important components of a ship's hull filler, which helps to keep the ship afloat and stable.