I played over 1000 games with gangplank so let me teach you how to play him.
I am not too good at English but I hope you can take as much info as you can out of this.
ps. A part of my guide wasn't translate. I will translate as soon as possible. sorry.
My GP Montage
remake gangplank play highlight
My kr GP guide : http://lol.inven.co.kr/dataninfo/champion/manualToolView.php?idx=110519
My Youtube Channel : https://www.youtube.com/user/phj1081
My Twitch Broadcast channel : http://ko.twitch.tv/sacommb