Talk:Gangplank/@comment-25301945-20150707211942/@comment-26590500-20150707225448

"One topic came up over and over again: buying items like Statikk Shiv or Ravenous Hydra and being able to Plunder several enemies with a single Parrrley. With this update, we added explosive barrels to Gangplank's arsenal so he can do just that and more."

Taken straight from the reveal page, so yes he does apply on-hit such as hydra. And for anybody wondering (like myself) his Q CAN still crit. It says so in the very last sentence of the "Teamfights" paragraph of the reveal.

http://na.leagueoflegends.com/en/page/champion-update/gangplank-sails-pbe