For some reason, my model won't unwrap. I have uploaded the model here: http://www.pasteall.org/blend/37735
One thing that surprises me is that if I try to select a ring, the ring stops at a certain vertex:
I have extended the ring manually, then clicked "Mark Seam", then I selected the upper lid and the lower lid of the barrel and also clicked "Mark Seam" for each of them.
When I now click 'u' and then 'Unwrap', nothing happens. I have been able to unwrap other models, but not this one.
Does anybody see where I might have missed something? Blender does not show any error message, it just doesn't unwrap.
Thank you for the help.
Edit: I have uploaded a new model here to reflect the suggested changes: I removed all doubles, I applied rotation & scale, and I put the same in a location where Blender could select a whole ring automatically. But it still won't unwrap:
Edit 2: Now here is a simpler model without the handles. It is really absolutely simple geometry (I think), but it still won't unwrap: http://www.pasteall.org/blend/37741
Could anybody have a look again? Thank you!