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GPS enables us to produce sketch charts quickly. Compared with real charts they are rough and approximate, but they do the job surprisingly well. Typically, for a bay we will use the dinghy to go right round the shoreline, taking waypoints along the way and marking any significant features. Then in the dinghy we measure the shallow areas with  leadline. The deeper areas are done from the big boat. In the early days we would just plot everything out on graph paper.

Nowadays, thanks to my good friend Paul Tobias, things are little more automatic and I can auto plot depths as I go. (At the moment I only do this from Ti Kanot, but a dinghy system would be possible). The depth sounder and GPS feed readings into a laptop computer. The main program used is Ozi Explorer which plots the depths. This is an excellent program but had a problems from my perspective. It only measured to the nearest foot. Paul created a program called Depths2ozi which plots to decimal feet and is easy to replot at various intervals, during which it will always choose the shallowest depth.

When I get the data I need on the screen, I do a screen grab, open it as a jpg in Adobe Illustrator and use that program to create the sketch charts.

When I need roads, I find it is hard to beat carrying a GPS on a bicycle and just riding around, plotting the results later. Using this method, I think this year I may have made the first ever map of Codrington in Barbuda.

click chart  to enlarge