Furthermore, internal flooding may spread over a large area through watertight fittings damaged by shock, or
through neglected watertight fittings.
Not all of these secondary casualties will be apparent during a preliminary investigation. If water is on the
opposite side of a bulkhead containing cracks or defective stuffing tubes, damage readily may be detected. If flooding
has not yet reached the area, however, damage may not be visible, and it may not be noticed until a degree of
progressive flooding has occurred.
Inspectors and other personnel must exercise care to prevent open doors, hatches, and scuttles from being
fouled in any manner that would prevent or delay their exit or their ability to resecure the opening. Should the motion of
the ship cause the door or fitting to swing, personnel should be directed to tend the fitting while open and resecure when
it is no longer required to open.
8-3. STRUCTURAL DAMAGE. Flooding usually is the result of structural damage below the waterline. It is vital to
prevent progressive flooding, and to remove as much of the water as possible in order to restore buoyancy and stability
and to return the ship to an even keel.
Investigation of structural damage must cover a considerable area surrounding the immediate scene of damage,
not only on the same level but also on decks above and below the principal casualty. Investigators must look for damage
such as fragment holes, ruptured pipe lines, warped or fractured frames and stanchions, cracks, open seams, leaky
stuffing tubes, bent shafts, improperly closed fittings, and severed electric cables, and must note quickly any damaged
bulkheads which indicate hidden damage which in itself could be as hazardous to the ship as the prime damage.
8-4. HIDDEN DAMAGE. The complete picture of a damage situation rarely is fully evident. Some damage may not
necessarily be within the immediate area. Shock, blast, fragmentation and other forces cause additional damage, which,
because of remoteness from the scene of the prime damage and not immediately apparent, could be overlooked during
the period immediately following the initial damage. The inspection of the ship for damage, therefore, must not be
focused solely upon the prime damage area. Minute inspection of the ship's structure, and of gages and meters on
piping and cable systems must be done. Open circuit-breakers and failure of operating gear could indicate hidden
damage which in itself could be as hazardous to the ship as the prime damage.
8-5. CHECK ADJACENT COMPARTMENTS. Investigators must understand that damage to compartments adjacent to
the one in which an explosion occurs is likely due to secondary penetrations and shock.
8-6. SOUNDINGS. All crew members should know where and how to sound all compartments in their own and adjacent