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TM 551915200SDC
CHAPTER 8
FLOODING
SDC FIXES SHALL BE USED ONLY IN COMBAT OR OTHER EMERGENCY CONDITIONS AT THE
DISCRETION OF THE VESSEL MASTER. DAMAGES SHALL BE REPAIRED BY STANDARD
MAINTENANCE PROCEDURES AS SOON AS PRACTICABLE.
Section I. FLOODING LOAD
81. GENERAL. Seawater weighs approximately 64 pounds per cubic foot. Therefore, the pressure over 1 square inch
at a depth of 1 foot is 0.444 pounds; at 9 feet, it is 3.9996 pounds; at 20 feet it is 8.88 pounds. The pressure at any point
is equal in all directions, whether downward toward the deck or horizontally toward a bulkhead. A bulkhead 20 feet wide
and flooded to a depth of 5 feet would be subjected to a total pressure of 16,000 pounds. P = 1/2 (64) (20) (52). At 8 feet
high and 20 feet wide and flooded to a depth of 15 feet over the deck, a bulkhead would have a total pressure of 112,640
pounds on it. This will give some idea of the pressures that must be contained. If the ship remained entirely motionless
in all three planes, the pressure at any given point would remain constant and the problem of shoring would be relatively
simple. It would be possible to erect a light shoring structure, and then leave it without further inspection. It may not be
necessary to shore.
a. Flooding loadsagging. The load on the ship's girder is increased by the presence of flooding water. The
increase in stress caused by this augmented load depends on both the amount and location of the flooding. Damage and
consequent flooding in the middle length increases sagging stresses. This increases the tension at the bottom and
compression at the top of the hull girder. Measures to correct trim caused by damage in the middle length should be
aimed to reduce sagging stresses. This may be accomplished by one or all of three methods:
(1) Pump liquid in the midships region overboard (either flooding water or liquid in intact tanksconsider
stability before pumping low weights overboard).
(2) Transfer liquids from midships region to ends.
(3) Counterflood high end (assuming good freeboard).
b. Flooding loadhogging. Flooding at the ends produces trim and increased hogging stresses. This will increase
tension at the top and compression at the bottom. In this condition, measures for the correction of trim to reduce hogging
stresses are:
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