What is meaning of Alternate Hold Loading Conditions on bulk carriers?

Alternate Hold Loading Conditions (Fully Loaded)

Heavy cargo, such as iron ore, is often carried in alternate cargo holds on bulk carriers. It is common for large bulk carriers to stow high density cargo in odd numbered holds with the remaining holds empty. This type of cargo distribution will raise the ship’s centre of gravity, which eases the ship’s rolling motion.

When high density cargo is stowed in alternate holds, the weight of cargo carried in each hold is approximately double that carried in a homogeneous load distribution.

To support the loading of the heavy cargo in the holds, the local structure needs to be specially designed and reinforced. It is important to note that the holds which remain empty, with this type of cargo distribution, have not been reinforced for the carriage of heavy cargoes with a non-homogeneous distribution.

Ships not approved for the carriage of heavy cargoes in alternate holds by their classification society must not adopt this cargo load distribution.

Fig : Alternate Hold Loading Conditions