We carry two netbook computers on board that we have come to depend on for many facets of our cruising life. We chose netbooks rather than full-sized laptops because they are inexpensive (< $200), consume much less power (< 2 amps versus 5+ amps), having smaller processors and screens, and are easy to carry with us to shore in a small dry bag. A viable alternative is Apple's iPad and we have seen several cruisers with these. Excellent applications are available and the built in GPS in some models makes them very useful for navigation. Our netbooks run Windows, which gives us access to loads of free or inexpensive software, useful on board.
When netbooks first became available a few years ago, I bought a little Asus EeePC, which came with the Linux operating system, 512 MB of RAM, and a 4 GB flash drive (no hard drive). Before we left on this cruise, I wiped out the operating system, which was no longer well supported, and installed a tiny stripped down version of Windows XP, specifically tailored for this computer. I added an 8 GB SD drive to store documents and navigation data, and installed the following software:
OpenCPN - a free charting/navigation program. We installed vector charts of the world, which provide detail to harbour level in most countries. We have a USB GPS that was easy to interface to this software and provides real-time positioning of our boat on the chart - very cool for those of us used to paper charts :)
Libre Office - MS Word/Excel compatible open source software (a light version of Open Office). We use this to write and do spreadsheet calculations.
Chrome browser for internet access/email.
Airmail - for Pactor II radio emails. Also needed to install drivers for USB to serial adapter to talk to the modem. This includes GRIB (weather) file viewer and weather fax software. Free.
WXTide - worldwide tide and current prediction software - free.
VLC media player - to watch movies - free.
Skype - to make phone calls.
PaintShop Pro V 4.0 - ancient (1998) but adequate image processing software
Avast antivirus - free edition to protect the computer when connected to the Internet.
PDF XChange - free PDF viewer with editing capabilities. This is great if you need to modify a PDF file when dealing with paperwork remotely.
Calibre ebook management software to manage our large collection of ebooks.
Our other netbook has similar software installed but adds MaxSea - a commercial navigation program and runs Windows 7. We like to use the built-in Microsoft software for photo management, which includes some nice tools to touch up and improve photos. We have found that with the slow processor in this machine that we need to resize (shrink) our photos before editing them with this software. For this we use Easy Thumbnails which allows us to quickly resize an entire folder of pictures (free software). The newer netbook has a 10 inch screen (the EeePc has a 7 inch one) so is much better for photo processing and watching movies.
Incidentally, OpenCPN provides an easier to view interface on these small computers than MaxSea, whose charts are very cluttered. Perhaps there is an option in MaxSea to improve this, but the program is complex and not all that intuitive, so we rarely use it.
The only limitations we have come across so far using these machines is that very high definition movies sometimes refuse to play properly. This has been a problem with only one series of videos, where each hour of video is about 3 GB. With smaller AVI files, we have not had a problem.