|
|
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 |
|
|
Alteration of speed |
|
|
Change vessels rolling period by changing GM |
|
|
By ballasting |
|
|
By deballasting |
|
|
Shifting of ballast, FO, FW etc and changing transverse position of G. |