Possible to model Viking longboat with Popsicle sticks?
On the assumption that you're going to try and mimic the clinker-built (that is, overlapping planks) construction of the real thing but not smaller details such as the riveting of planks together with trenails, then you should be able to use popsicle sticks for the planking - as you said you'll want to shape them with hot water (or better, steam) to get the correct shapes.*

Where you'll struggle with popsicle sticks alone are the large, complex shaped timbers like the keel, bow/stern posts and keelson. For these I'd recommend buying some larger pieces of basswood and carving them to shape rather than sticking popsicle sticks together. You may also find it easier to carve the frame timbers from basswood also.


For reference, this is a picture of a longship I took last year, showing just how huge the keelson is.

*I suspect that the popsicle sticks are too brittle to attempt riveting or similar (the wood in viking ships was usually worked green not seasoned), but if you're just glueing them together they may be fine