Canon barrel

[fernando]

Originally Posted by Pukka Bundook

...I am No expert, but first thoughts say a swivel gun from a ship.
The condition says it was in salt water for a long time too...

Perhaps the cause for such excavation, Richard, is more due to it not having being immediately treated after being rescued than the time it stood under water.
As i read, while bronze pieces can be brought in (relatively) less chaotic conditions to contact with open air, those in iron tend to quickly disintegrate if not sank in water tanks and submitted to treatments like electrolysis.