Dynamic Positioning Data - Enviro Calculation Tab
- Last UpdatedDec 18, 2025
- 2 minute read
This calculation allows you to specify the maximum available thrust in each unit and determine the maximum environment the vessel can operate in for a range of specified environmental directions. The current speed is fixed and the maximum wind speed and wave height can be determined. Rudder effects can be included and operated either dependently or independently.
As with the Dynamic Positioning Data - Miscellaneous Tab, the wind directions are specified, and the wave direction is given relative to this. The current direction may also be given relative to the wind, or may be fixed in a particular direction.
Wind
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Initial Wind Direction |
The first wind direction (degrees). |
|
Step |
The wind direction step (degrees). |
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Maximum Wind Direction |
The maximum wind direction (degrees). |
Waves
For the Enviro calculations, the wind speed and wave height/period are assumed to be correlated either from the wind-wave relationship supplied on Dynamic Positioning Data - Miscellaneous Tab.
|
Wind-Wave Offset |
The wave direction may be specified relative to the wind direction by giving an offset in degrees. A zero offset assumes that the wind and waves are coincident. |
Current
The current direction may be specified in a similar way or may be fixed in one direction which will usually be either head on or beam onto the vessel.
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Fix Current Direction |
Checking this box will mean that the current will be fixed in one direction for all wind headings. |
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Current Speed |
The current speed (knots) |
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Current Direction |
The current direction (degrees). This is only required if the current direction is fixed. |
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Wind-Current Offset |
If the current direction is not fixed, then an offset from the wind direction may be entered (in degrees). |
Available Thrusters
The Enviro calculations can be performed with some thrusters inactive. Uncheck the available box(es) if thrusters are unavailable for this run.
Note:
A minimum of 3 thruster units must be available to perform the Enviro calculations.
In addition to switching some thrusters off, the thrust available can be limited by setting the Percentage of Thrust Available. In this case, the maximum thrusts, as specified on the Thrusters page are limited by the percentage specified.