What is the purpose of Ventilation? When do you Ventilate a cargo hold during voyage?

Purpose of Cargo hold Ventilation

1. Prevention of cargo or ship sweat.
2. Removal of taint or smell of previous cargo
3. Prevention of build-up dangerous gases
4. Supply of fresh air to Live cargoes
5. Removal of heat that is given off by certain cargoes

* VENTILATE if the dew point of the
air inside the hold is higher than
the dew point of the air outside the
hold.

* DO NOT VENTILATE if the dew
point of the air inside the hold is
lower than the dew point of the air
outside the hold.

Ref: Cargo work book by Capt Errol Fernandes