When you are at sea for a few weeks or amongst islands that have no technical resource, it is not uncommon to lose all you electrics simply by not having a charge source.
So in addition to an expensive chart plotter, you also have to have passive charging systems. Many of the cruising boats out there have none of that stuff and most have a modest house bank as well.
So of you have just an alternator, it doesn't matter how many electronic devices you have, they will all have flat batteries. No lightening strikes or other exotic happenings, just a dodgy alternator is all it takes.
Anyway, in NZ we have always had to pay for paper charts so excuse my lack of concern for you plight
One of the biggest shockers for me, is how much amperage can be required simply to keep a laptop running... If I'm somewhere playing on the computer for much of a rainy day, my wind generator had better be spinning bigtime, just to break even with the demands of refrigeration and my MacBook's 12V converter... I can't imagine running a laptop all day for navigation, even the draw of my chartplotter(s) alone adds up pretty quickly over the course of 24 hours, and I've always suspected that most people who are running these devices all the time are doing a LOT of motoring, as opposed to sailing... Even with solar and all the rest, prolonged periods under sail alone just isn't very conducive to keeping such an array of gadgets up and running, and many of the bigger boats I run require at least an hour or two of generator run time every day, just to keep up...
Unless I'm being forced to do otherwise by a schedule, I like to sail as much as possible... Cruising in a place like the Canadian Maritimes, where one might see overcast and light air conditions for days at a time, you won't get much power generation from solar or wind, and running a plotter or computer full time can quickly run my bank down... In such situations, if I don't need to be running radar, I'll shut everything down as much as possible, and simply rely on my trusty old Garmin 48 handheld GPS and paper charts, over a period of days it can make a huge difference in power consumed... For there is nothing I hate more, than having to run my engine simply to charge my house bank, or any peripheral 'devices' I might have aboard...
I will admit, however, that it sounds like an iPad or similar tablet has changed this equation, bigtime... Everyone I know is telling me I NEED one, and it's just a matter of time before I go down that road... We shall see, but I still think I'm too much of a dinosaur at this point to ever be comfortable without the appropriate paper aboard... :-)