What are factors which causes Vessel to list during Voyage or Sailing ?

If a list occurs that is not caused by normal use of consumables (water and fuel), such list can probably be attributed to one of three caused or possibly a combination of same.

 Cargo shift

1. A major shift of deck cargo will obviously be immediately apparent: Deck cargo may, however, have shifted imperceptibly or there may have been a shift of cargo below decks. An immediate examination should determine whether or not cargo has shifted and if this is the case the Master will have several remedies available to him depending on the exact circumstances.

2. The ballasting and transferring of ballast or fuel to reduce or correct a list caused by a shifted cargo should, however, be carefully considered since this action would, in all probability, result in a far greater list if the cargo should subsequently shift to the other side.

3. As any cargo shift will in most cases occur in adverse weather conditions, sending crew to release or tighten the lashing on a shifted or moving cargo may well represent a greater hazard than retaining an overhanging load.

4. A moving or shifted timber deck cargo should only be jettisoned after careful consideration; jettisoning is unlikely to improve the situation as the whole cargo stack would probably not fall at once. Severe damage may also be sustained by the propeller if it is still turning when timber is jettisoned.

Water ingress

1. The possibility of water ingress should immediately be determined by sounding throughout the vessel. In the event that unexplained water is detected, all available pumps should be used to bring the situation under control. Subsequent actions will obviously depend on whether or not such ingress of water can be controlled by use of pumps.

 Angle of roll

1. If the rolling of the ship prior to the detection of the list has been exceptionally slow and the ship has returned to the upright position in a sluggish manner, this will indicate that the ship has little or no metacentric height remaining.

2. The list is therefore due to the ship rolling to one side and having no righting arm to return to the upright position. This situation may be rectified by either adding weight to the low part of the ship (ballasting DB tanks) or removing weight from the high part (deck cargo). Of the two options, ballasting is usually preferable and if empty divided double bottom space is available, the tank open the lower side should be ballasted first in order to immediately provide additional meta centric height – after which the tank on the high side should also be ballasted. However, special care should be taken in ballasting and de-ballasting to rectify the situation since this may cause a far greater list to the other side.