Very interesting thumbnails, each with its own merit, it's so hard to choose >.<
I think 4, 7 and perhaps 8 are weaker in terms of showcasing the whole 'new on old' theme which in this case is the ruins on the ships.
1, 3, 5 I think have the most potential to show what you want to show, though they are more standard in terms of composition (which is not a bad thing to be honest).
I'd say go for a mix of 1 and 5, but that's just my opinion. If you feel stronger about something else, go for it. Cheers!