It is particularly important for combination carriers to
have their holds inerted because whenever a hold in an OBO carrier
(which could extend to the full breadth of the ship) is partially
filled with clean or oily ballast, water agitation of this ballast
can occur at small angles of roll and this can result in the generation
of static electricity. The agitation is sometimes referred to as `sloshing'
and it can happen whenever the ullage above the liquid level of the
hold is more than 10% of the depth of the hold, measured from the
underside of the deck (see figure 18 for
remedy condition).