Describe the various effects on a ship behavior, which can be expected as a result of
entering shallow water.
When there is limited UKC the restriction in the velocity of the water flow which causes a dropentering shallow water.
in pressure. This reduces the buoyancy force of the v/l. since the weight of the ship unchanged
the v/l will tend to sink further thereby increasing draught in order to resolve equilibrium.
There is also likely to be a change in trim because the LCB is likely to change thereby creating
a trimming moment.
EFFECTS:
1. Vessels take longer to answer helm.
2. Response to engine movements becomes sluggish.
3. Vibrations will be set up.
4. Extremely difficult to correct a sheer.
5. When a ship is nearing an extreme shallow depth of water such as shoal. She is likely to
take a sudden sheer, first towards it and then away.
6. The bow waves and astern waves of ship increase in height.
7. The trough which normally exist the quarter become deeper and the after of the ship drawn
downwards towards the bottom.
8. Increase of time due to squat.
9. The increase in the propeller speed, increase efficiency of the rudder but will not increase
the ship’s speed.
10.Transverse thrust of the propeller will change.
11.Minimum RPM to maintain steerage is more than normal.
12.Color of water changes.
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