Seakeeping - Long Term

Any motion, including those defined in the Seakeeping - Additional Calculations page can be assessed by the long-term calculations routine.

Wave Data File

A wave data file contains a list of sea areas, and for each sea area an array of probabilities for encountering a particular significant wave heading and wave period. This wave data file should be produced in ASCII format, but is converted to a binary file upon initiating the long term calculations. Subsequent calculations are performed using this binary, direct access file directly. The format of this file is given in Wave Data File Structure.

Motions

All available motions are contained in the three drop-down lists. You may select up to three motions, remembering to check/uncheck the appropriate boxes and to enter limiting criteria.

The speed for the long-term calculations needs to be selected from the drop down list containing the speeds used in the short term seakeeping prediction.

Voyage

The voyage data section of the property page is set out in a fashion similar to a spreadsheet and initially appears blank. You can enter several Sea Area ID's, each with an associated Course and Time weight, either manually or from a voyage file. To enter data from a voyage file, click on the Open button on this page and a file selection box appears for the voyage file to be specified. To delete a sea area, change the ID to zero. A set of voyage details can be saved to a voyage file by clicking on the Save button. The format of the file is given in Voyage Data File Structure.

It is your responsibility to ensure that any sea area in the voyage file exists in the wave data file.