I don't know if this is a bug, or it just happened without a reason. Yesterday, when I boarded a Fleuron class 3rd rate ship with my 5th rate warship, a bug occured. Instead loading the battle into ship deck, I was on the sea with my crew and enemies crew. They were swining the swords but were not making any damage. Then I pressed the F12 key and the battle loaded into captains cabin. I defeated the captain and I got the new ship, which, to be honest I wouldn't be able to achieve if the bug didn't happen. Just to let you know that I'm playing the Beta 4 WIP version. Here are the photos:

