The navigators place of work !
Here are some tips, recommendations and ideas for using GPS and waypoints.
- When using someone else's waypoint always plot in on your charts - this
will help you answer the questions is the waypoint correctly written down, is
the waypoint a safe waypoint to use for an approach - i.e. does it leave
sufficient margin to pass hazards safely during daytime/hours of darkness, is
it safe to use from the direction I expect to be approaching ?
- When defining your own waypoints, plot them on your chart, and work out
the true bearing and distance between each. Using the 'distance function' on
your GPS to give you a bearing and distance between each pair of waypoints you
have entered - if the information on the GPS does not tie up with the same
information obtained from the chart then you have an error to be found
(typically errors made when inputting way point lat and longs into the GPS).
- Be wary of mixing waypoints, e.g. some waypoints defined as the precise
coordinates of a navigational mark, whilst others are defined as say 0.5 mile
away from a mark.
- Check way points before using, e.g. you may have set a way
point for a bay on one occasion when you were approaching the anchorage from the
east - but the same way point may not be safe to apr0oach from the west - this
will be readily checked if all your waypoints on plotted on the relevant
charts before they are used
- Set up guard zones around hazards - to give you early warning of their
- Note the datum used on your GPS and that used on the chart. Different
datums can be selected on most GPS receivers, and charts will indicate the
amount of adjustment for positions between the charts and datum and that
typically used on GPS equipment (WGS82 ?).
- Before heading for a waypoint stored on your GPS, double check where it is
on the chart - should a new waypoint with a greater offing be entered on
account of a lee shore, of difficulty judging distance off at night ? This
where pre plotting waypoints on your charts can save you time.
- Consider what information you could use should your GPS fail.
Some illustrations are currently being created which will illustrate the
- Waypoint clearing line - examples to help negotiate coastlines and traffic
separation schemes (TRS).
- Waypoint web - how to clearly determine the boats position without