I said there can be a capturing animation (the lowering of the corvus onto the other ship). Also, we can make the loyalty line show up above them and a "capturing" icon, complete with some ambient sound effects of battle. 

I think there is no coding needed to make this. However will not look as good as you imagine: just one boat touching another, and some capture point going down for the victim boat basically.

@wowgetoffyourcellphone, please let us know  if there are some tickets in gitea for this idea or somebody should create it (for example me?)...

I think it could be done with a special boarding ship for the Romans: Corvus Quinquereme. It would come alongside the enemy ship and lower its Corvus onto it and slowly drain its loyalty. All other civs could have a late-game "Marines" tech to mildly counter this. Much like with capturing buildings, the more troops garrisoned aboard each ship affects the capturing rate (but never drops it to zero; we need to improve this with building capturing methinks). I think showing men jumping onto enemy ships and battling it out is not feasible. Not only that, but would add tedious micro and we want to reduce the size of ships for better pathing, so the scaling would be wrong. Best to just show a capturing bar or loyalty bar slowing draining down like we do with buildings. 

@zyliThanks for going all the way and test it. Your approach will work. Isn't the underlying problem that the scenarios in their current state are not compatible with any newer version of 0ad? This is why i suggested to port the scenarios,  itś seems like the more sustainable solution plus you get new features and fixes. @NewWorldHero have you already tried to port them and how many are there? What do you meant by somewhat modified? that is what i wanted to suggest, to use the migration scrips to port them.  The fact that your scenarios kept you on A23 (which was a great version) for so long got me curious. Could you maybe share them here?