Through the advise given below about a back up portable computer, I have decided to get a Windows based perationg system back up. So I will look for a non Mac back up.

Now that this is decided, I have another question. I do a lot of sailing. The on board power system is DC, 800 amp hours from AGM batteries, no DC to AC inverter. Is there something I can use to connect,plug, my computer into that will get power directly form the on board DC power.