Theory of operation

The program uses a model of the tidal flows occuring in the English Channel. It relates this model to the magnitude and state of the tide at short intervals during the planned passage and calculates the tidal vector that is likely to affect the vessel at each interval. It integrates this with the vessel's speed and heading for the same interval and re-calculates the vessel's course accordingly.

It repeats the process above and adjusts the heading at each iteration until a heading is found that takes the vessel to within approximately 100 yards of the destination position. It uses this last iteration to calculate the waypoints and ETA.. It then displays the ground track on the minichart.

 

Accuracy and reliability

The program is tested repeatedly each year and the results compared with those obtained by careful manual plotting.
 

Available features

Departure and destination points may be entered manually by clicking on the minichart, or by selecting from a list of user defined waypoints. If your GPS receiver is connected to a serial port on your PC it can be used to set your current position as the starting point. There is a facility for importing the departure point and/or destination point from the shareware OziExplorer chart program. Departure and destination points can also be imported from Maptech's Offshore Navigator and Chart Navigator Pro navigation software. There is a function to swap the departure and destination points to reverse a route.

Once a route has been calculated there is a facility for optimisation of the start time. This will find the start time, within 6 hours of the initial start time, that produces the fastest passage. The recalculated route is then displayed.

The list of waypoints produced by the program can be viewed, printed, saved and exported to the OziExplorer program or to your GPS receiver. They can also be exported in formats suitable for Maptech Chart Navigator Pro, Euronav seaPro and SeaClear II plotter programs as well as the G7ToWin and Waypoint+ GPS management programs.
 

Disclaimers  

• Many of the features listed above are unavailable with the 10 day trial version of the program. They are enabled when the program has been registered.
• Importing the departure point from your GPS is dependant on a satisfactory connection between the NMEA output from the GPS and a serial port on the PC.
• The export of waypoints to GPS is dependant on the above and on the ability of the GPS to receive the standard NMEA "WPL" message. Check this with the GPS manufacturer's specification.
• This program should only be used as an aid to navigation and does not obviate the need for good seamanship practices.