2014 © Graham Rabbitts [You are welcome to use original material from this site, but the source should be acknowledged]


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Having had a couple of seasons trialling the Jeppesen charting system, I have decided to revert to the Australian Digiboat Software on Board (SOB) chart display system that appears to be robust. It uses C-Map cartography. In line with the licence conditions I have three copies

- on a small Dell laptop with solid state drive  for use while sailing

- on my main Dell laptop for generating Logs

- On True in New Zealand for navigation

It has turned out to be a great success, especially running on a very compact Dell laptop


Installation details are on the  Instrumentation page.

The large Dell laptop consumes a lot of power, but the compact Dell notebook  uses so little power that we have been able to leave it on throughout every passage, so I have an accurate track recorded for the Log. The use of this recorded data for is described elsewhere, and I have developed some special techniques for displaying tracks

To provide navigational data in the cockpit, I used a Raymarine autopilot remote control. The first was connected to the Seatalk system by wire, but my current version is wireless. It can display most nav data including COG, SOG, DTW, BTW, depth, speed, and wind direction (true and apparent).

We thought of adding a small plotter under the hood, rather like the one on True, but that looked tricky in terms of location, and the need to arrange additional power and NMEA data feed, quite apart from the not inconsiderable cost. A far simpler solution is to simply place the laptop on the main hatch. It has a battery life of a few hrs, and with a chart reader and a USB GPS dongle functions quite adequately in those few situations where a plotter on deck is desirable. Works well!

I also carry Navionics charts on my Android phone. This is small enough to hold in one hand while steering with the other when piloting in confined waters, though the phone does tend to power down at inconvenient moments. I now have an Android tablet, and if I cruise outside the Solent area again, I will put Navionics on that.

My most recent purchase is a set of UK Admiralty raster charts from  Sea Clear in Cowes. Displayed on a GPS-enabled  Android tablet using a Marine Navigator app. The lot cost less than £35 (excluding the tablet). Incredibly useful for finding laylines when in the cockpit.

Go Top

Software on Board You Tube demo

Go! >>

Digiboat website

Go! >>

The video above shows an animated track. It is colour coded to the boats speed  over the ground.

Windtails are shown for part of the voyage from L’Aberildut to Falmouth