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*Vessel Velocity |
 
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*Vessel Velocity
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*Vessel Velocity |
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To specify a vessel constant velocity horizontal velocity.
Refer to Vessels and Vessel Motions for further information on this feature.
A block of two lines to define constant vessel velocities which is repeated as necessary.
VESSEL=Vessel Name, [AXIS=Axis System]
Speed, Angle
Data for any Vessel Name specified here must be input under *VESSEL INTEGRATED. As this keyword is used to specify that a constant vessel velocity is to be combined with high frequency vessel motions, it may not be used in combination with *VESSEL TIMETRACE for any particular vessel. This keyword is not relevant for frequency domain dynamic analysis.
Axis System can be either GLOBAL (the default) or LOCAL.
Input: |
Description |
Vessel Name: |
The name of the attached vessel. |
Speed: |
The constant vessel speed. |
Angle: |
The motion direction, measured in degrees anti-clockwise from either the global Y-direction or the local surge axis. The default is 0°. |
Axis Type: |
The options are Global (the default) and Local. |
(a)The velocity you specify here is integrated to define a time history of horizontal motion in the direction you specify, and this is simply added to the vessel displacements from other sources.
(b)The choice of axis system refers to data you specify for vessel constant velocity motions. Motions in this context means translations only – rotations always refer to vessel axes. Naturally Global stipulates that translations represent drift or combined motions in any or all of the global X, Y or Z axes, and/or that the angle you specify in defining a constant velocity is relative to global Y. Conversely Local indicates that translations represent any or all of heave, surge or sway, defined with reference to the initial orientation of the vessel axes, or that the angle you specify in defining a constant vessel velocity is relative to the vessel surge axis.