Vessel rolling heavily. | |
There is no period of lull, rolling angle is almost same or increasing in every roll. | |
Vessel is encountered by the same phase of wave almost all the times. |
Synchronized rolling to be determined immediately. | |
Occurs when the period of roll is equal or nearly equal to the apparent period of encountered wave. | |
A very dangerous and undesirable condition. | |
Successive waves tend to increase the angle of roll of the vessel, thereby produce danger of capsize. | |
More dangerous in small vessels or vessels with low stability. | |
Most dangerous when a beam sea is experienced and the ship reaches a greater maximum inclination at each trough and crest of wave. | |
Danger of cargo shift. | |
Danger of damage to vessel. |
Change apparent period of waves by: |
Alteration of course |
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Alteration of speed |
Change vessels rolling period by changing GM |
By ballasting |
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By deballasting |
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Shifting of ballast, FO, FW etc and changing transverse position of G. |