The seller of the item you linked to also offers a 400 mA version. Just running the nav lights for a few hours could probably be made up for in three days with that, almost certainly if you got two of them. If you are running the nav lights all night, plus blaring the stereo, and expecting to have your batteries charged in three days you might need something like SD linked to.
Allowing a 2 amp draw for 10 hours (say, running an anchor light over night) would be 20 Ah, which would require 50 hours of charging at .4 Amps. With two of those panels, that would bring it down to the equivalent of 25 hours of peak charge output which you might be able to get in three days, but it would be close, I imagine. I don't know whether those actually put out anything near the advertised current. I'm thinking of trying something similar in my boat, but haven't yet.
Cape Dory 28 "Dulcinea"