Thank you for the great information. I never knew I would be talking to an eye-witness regarding it! If i may ask a few questions, not to contradict but to clarify since I've only seen 2 pictures of it:
I have no doubt that the hoops were forge welded and shrunk on hot, however they really look insubstantial as far as actually strengthening the barrel (confer other hoop/stave barrels where the hoops are quite large). Is it possible it is a solid, welded barrel (not staves) and the hoops are there as decorative or other purposes?
Regarding the tang/tiller: If there was originally a long tiller, how long do you think it was?
From the perspective of the 2 photographs, the end actually looks rather flattened and curved down, similar to how your "alcove cannon" here is attached .
http://www.vikingsword.com/vb/showthread.php?t=18049
Is it possible this one was adapted to such a configuration?
Do you have any idea the caliber of the piece?
Thanks