Investigators will wear oxygen breathing equipment when entering the damaged area, work in
pairs, and maintain communications with assistants outside the damage area. When the
situation permits, no closed space or void will be entered until the area has been cleared by the
gas-free engineer. Should fire, flooding, or other factors prevent first clearing the area by the
gas-free engineer, investigators will continue, but assume that hazardous conditions exist such
as the presence of flammable/'explosive or toxic fumes and that the space does not contain
adequate oxygen to sustain life. Serious personal injury is possible.
Preliminary investigation of damage. The degree of investigation required immediately after a ship has
suffered damage depends upon the location and the extent and type of damage. Certain information as to the extent of
damage will be available almost immediately.
Heavy shock and whipping of the hull structure may indicate a major underwater explosion, although intense vibration
will not always occur on large ships. A decided or progressive change in trim or list indicated by clinometers will also
provide information. Additional information will come from gunnery and ship control stations, and from roving patrols
near the scene of the damage. For example, the bridge may report that steering control has been lost, and engineering
may report that water is coming through a certain bulkhead.
The foregoing information is preliminary, but combined with reports from lookouts and other topside personnel, or from
below-decks personnel, it will locate the damage and give a general picture of its extent. On the other hand, there may
be a few obvious signs of damage:
a minor loss of power, smoke, a dropping pressure gauge, unusual temperature
change within a space or on a bulkhead, or a slight seeping of liquid at a seam. All of these indications should be
investigated thoroughly. They are symptoms of a dangerous condition, and prompt remedial action must be taken if the
ship is to survive.
Four basic principles of investigation:
Investigation should be thorough.
Investigation should be conducted with caution.
Reports should be accurate.
Investigations should be repeated to guard against overlooking subsequent or progressive damage.
Ships have been lost or have suffered unnecessary fires or flooding damage merely because investigating crew
members have neglected one or more of the above principles.