It is difficult or impossible to ventilate in sea transportation, even without ventilation, which is harmful. This is practical experience.
1) It is difficult to ventilate: Considering that the movement of bulk grain in the cargo hold causes the ship to tip over and lose its stability, resulting in a vicious sinking accident, SOLAS has strict regulations on the loading of bulk grain. The most important one is to fill the cargo hold with bulk grain to eliminate or minimize free grain surface. The pressurized water tanks and high hatch coaming on both sides of bulk carriers embody this design purpose. In addition, a funnel is set in the upper cabin to fill the space of the lower cabin due to the difficulty of trimming or the sinking of the lower cabin in the way. If there is too much free grain surface, it should be covered with bagged grain or covered with cloth and tied with wood strips to prevent loose grain from moving. Therefore, it is difficult to ventilate the cargo bay when it is full or its surface is sealed.
2) No ventilation: Although loose grain may sink in the way and form small area of free grain surface, these small areas are too small compared with the large volume of grain, and it is difficult for the heat of large volume of goods to be emitted from the surface of small area. But this is only "no ventilation" in a desperate situation.
In addition, also have liquid bulk carrier on the international carriage of scattered valley, because of ship structure, the ship's cargo tank without tube, if little by little cargo tank hatch and thin air pipe is not the role, unfavorable also open for ventilation on the sea, but this type of ship in sixty and Argentina to Europe in the seventy s are commonly used to transport the corn, but did not damage occurred because of not ventilated. But this only shows that the lessons learned from practice do not require ventilation.