James Brener of Lorton, Virginia, asks:

"I’d like to get a laptop computer for the boat so I can get Wifi at the dock, run electronic charts, and access web–based weather and radar when I’m underway. What specifications do you think are important when buying a laptop for use on a boat?"

Tim Bartlett replies:

In terms of headline specs you really don’t need to worry. The recommended hardware for most navigation software is something like a 1GHz processor with 1GB RAM and 40GB HD. You should also have a decent screen—800x600 resolution is about the minimum—and a DVD drive. That means navigation software will run quite happily on any of the current entry-level laptops, although you do need to be careful if you are thinking about a netbook or mini.

Charts use up lots of storage space and software always runs better on a machine that has more RAM and a faster processor. Sophisticated programs like the MaxSea will be happier with a 2GHz processor, 2GB RAM and a 120GB HD.

You’ll also need at least two USB ports—one for a GPS receiver and one for a USB mobile broadband connection card. Having more USB ports is always an advantage, particularly if you, like me, prefer using a track ball stuck to the chart table rather than the touchpad on the laptop itself. The same thing applies if you use a serial-USB converter to get NMEA 0183 data in or out of the laptop.

Many new PCs now come with Windows Vista as the standard operating system and even though most mainstream navigation packages have made the transition to Vista, lots of smaller interesting applications have not. If possible, get a machine that runs Windows XP instead.

None of this advice will be worth much if you can’t power your laptop. The standard solution is to get a small inverter to convert the boat’s 12-volt DC power supply to 115V AC and then use the laptop’s charger to convert the AC current back to 17 or 19V DC. A neater, safer and more efficient solution is to get a DC-DC converter (available from many online retailers or from local electronics stores) that steps the 12-volt supply directly up to 17 or 19 volts without going through an inverter.