I've tried Imray, RYA, Cmap and Maptech Offshore Navigator Lite software packages, at sea in sailing yacht, and after some time have fixed on navtech in my trusty laptop with inverter and specially built little teak book rack which sits behind chart table screen allowing the laptop screen to be viewable over top and a mouse on table. I have some vision loss but this works very well for me. I print out routes and chartlets on A4, file in plastic pouches to take on deck for pilotage. I have sailed a Sadler 34 from Chichester, west about to Ireland then north to Orkney and Shetlands and down to NE England during a series of long weekends and one week's leave this year so have proved its worth. The laptop often simply sits on the table with a bit of non-slip sheeting under in fine weather. Only problem is associated with windows software and is overcome by the starting up sequence. Its a very sensible alternative to a chartplotter, also can pick up weather and nav data on laptop, send email, video, DVDs, music, digital camera photos, etc carry Laptop in amoured plastic box to and from boat when in Dinghy. As you can see I'm a convert to Maptech lite and will probably update to Pro when I need 3d underwater facility! but my chart case, folios and sailing direction bag are always with me. fair winds, lee ho! John Harris - Caol ila