If a list occurs that is not caused by normal use of consumables (water
and fuel), such a list can probably be attributed to one of three causes, or
possibly a combination of same.
Cargo shift
6.3.1 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 upon the exact
circumstances.
6.3.2 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.
6.3.3 As any cargo shift will in most cases occur in adverse weather
conditions, sending crew to release or tighten the lashings on a moving or
shifted cargo may well represent a greater hazard than retaining an
overhanging load. A moving or shifted timber deck cargo should only be
jettisoned after careful consideration it 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 still turning when timber
is jettisoned.
Water ingress
6.3.5 The possibility of water ingress should immediately be determined
by sounding throughout the ship. 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 upon whether or not such
ingress of water can be controlled by use of pumps.
Angle of loll
6.3.6 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. The list is therefore due to the ship lolling
to one side and having no righting arm to return it to the upright position.
This situation may be rectified by either adding weight to the low part of
the ship (ballasting double bottom 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 on the lower
side should be ballasted first in order to immediately provide additional
metacentric height - after which the tank on the high side should also be
ballasted. However, special care should be taken in ballasting and
deballasting to rectify the situation since this may cause a far greater
list to the other side.