Historian Arthur Herman directly attributes Britain's ability to forge bronze cannon with her domination of the seas and, as a result, her empire. Pick up To Rule the Waves if you have time. Its a great read.
Fascinating find. I wonder how much they'll be able to bring up & display.
Crap - I got it backwards. According to Herman Britain out produced Spain & Portugal, who relied on bronze which were far more difficult to make, by effectively forging cast iron cannon.
I believe the switch over started in the late 1700s. But even during the French Revolution/Napoleon Wars many British Frigates and Ship of the Lines still had bronze cannons. They are shorter range then the iron long guns, but much bigger caliber. The bronze cannons were usually 32 pounders, but the iron ones were usually 8 pounders with perhaps a couple of 12 pounders per ship. The French were building new bigger and faster Frigates at the time and they all had cast iron cannons with the exception of a few bronze cannons for close in work. The Spanish were already waning and had not made the change over.
From: The Frigates (Wordsworth Military Library) by James Henderson