Someone's having way too much fun? Or is da enemy using new ammo?

[Simon Ye.S]

Anyone else ever get hit and damaged by an explosive cannonball?

We were sailing of the coast of Cutthroat and I was getting ready for one last broadside on the mid-level Spanish flagship, when out-of-the blue, we were hit with an explosive cannonball from an unseen source! I landed the broadside, and right as the green arrows appeared, we got hit again by a second explosive cannonball. Everything frozed up after that. We got sunked and all had to log back in.

Did these ships add another arsenal? Or do you think there's some mischief going on? We were on an open server so how could another players ship damage us?