Making the switch

Ali Wood recalls her first passage using electronic charts

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When I took delivery of PBO Project Boat Maximus, I used electronic charts for the first time, but only in combination with paper charts. It had been two decades since I'd studied my RYA Yachtmaster theory, and I wanted to be sure I could adequately read a paper chart before getting to grips with electronic plotting!

For the voyage from Chichester to Poole, the first thing I did was work out the total distance and our average boat speed for the Maxi 84. This would give me the rough time it would take (tides would come later). Using Imray charts and a pair of dividers I counted 47 miles, which I sense-checked against the distance tables in the Almanac.

With a winter passage and dwindling daylight hours, I decided to do the voyage over two days, with a stopover in Yarmouth, Isle of Wight. This allowed me to choose favourable west-going tides. Once I knew what time high water was, I could check the strength of the tidal stream in the Admiralty Tidal StreamAtlas or the PBO Small Craft Almanac.

It wasn't just about the tides, though, I had other factors to consider, such as the winter bridge opening times in Poole and the current at the harbour entrance.

Having plotted my route on Imray's glorious new-smelling charts, I decided to compare my hand-crafted route to that calculated by the Navionics app on a tablet. I found it very easy to plot a course both manually and automatically. You simply enter your boat's draught, circle your start and finish waypoints by pressing down your finger, and bingo, it does it all for you, correctly following the buoyage.