How do I Gangplank late game?

Been playing the salty pirate and have been having lots of fun and great success plundering the enemy top laner's booty. However, come late game, i'm at a bit of a loss as to how I should be participating in team fights. So far i've just been just dropping barrels during the fight and taking advantage of the enemy team ignoring them (because they're engaging my team's front line).