Using external AIS and GPS and OpenCPN via Windows/Linux on a smartphone for sea navigation
First, there's really no way to emulate modern Windows PC's on Android, and there is a long list of reasons for that. So to be honest, you're simply not going to be able to run Windows software on an Android phone.

That said, OpenCPN can actually be run on android. And googling shows that there are some "easier" guides for making it happen. Many Android devices already have a built-in GPS and communications hardware, which (I assume) would be sufficient for your needs as long as you're in coastal or inland waters (Where you have a data connection). I wouldn't be surprised if some AIS Dongles worked with Android without need for drivers, giving you AIS access virtually anywhere at sea(But I could be very wrong).

As for AIS as a separate feature, there are actually quite a few AIS applications available for Android with varying feature sets. I don't think I have enough information to determine if they have the features you need, but feel free to look at them. Here are some links, if you haven't already found them yourself:

Boat Beacon, MarineTraffic Ship Positions, and mAIS - Ship Position Reporting

Now, on to the down-and-dirty: If you want a seamless, power-efficient setup "That Just Works™", then Android most likely isn't going to be the answer. I would suggest looking at low-power Atom-powered Windows tablets. You can keep Windows or, alternatively, install Linux on them. They draw considerably less power than an average laptop and are quite capable.

TL;DR... OpenCPN works on Android. And you can get how-to guides on making it happen (needs root). There are AIS Applications for Android (Links above). Finally, your best bet is probably a cheap Windows tablet, not Android.

I suggest this tablet, or anything similar.