It depends on who made the tubes...Paul Tilly made the early tubesets in hypalon for Otech while the navy later re-placed most of them Wing tubes which are PU.
The navy was pretty good about swapping out tubesets when they decided to switch to PU. I'd be surprised if you had hypalon tubes. Post a picture?
For Wing PU tubes, I like Clifton:Clifton 2-Part PVC/Urthane Glue for pvc boats, 32 ounce
I was told this what Wing uses.
EDIT: If it's the boat in your album of pictures, those tubes look to be made by Wing and are PU. The boat looks to be the Otech that JohnDoe007 used to own.