This build is a little different from the other builds because I love the feeling of walking into a fight and utterly destroying someone. Thats just me though. As for Gangplank, CritPlank, or Gp he is an amazing top layer. He has a ranged poke, a cc remove and massive heal, and a fun global ult. Which can make him extremely strong.

Your Q (Parrrly) is wonderful for farming. It gives bonus gold for a kill on a unit, and half of the mana cost is refunded. So you can farm safely away from the other enemy top. He can struggle with mana if your poke heavy or use W (remove scurvy or citrus) too much. His W has a fairly high cost, but its reasonable because it removes all cc. Yes all of it slows, stuns, suppresses, and silences. Oh I forgot, also heals, for like a quarter of your health. If you stay of heavy poking or using the heal too much the mana isn't a problem. That is why I don't build mana region.

Now you should finally have some money to get core items. Also you have your ult. The most versatile thing you have. I use it to pick up as much gold with it as possible. Such as you see a teammate close to a kill but can't catch them. Ult in front of the enemy utilizing the slow of the ult to ensure the kill. It can be used to help someone escape, no where near as fun but for the best of the team. Its also great it you are being dived on. Pop ult under turret and kite them, that has gotten me a lot of double kills and some laughs.

At this point you are a 1v1 god. The damage you deal is crazy, you can easily two shot people. don't get caught by a group because while you can come out on top, you are mostly going to get more cc than you can handle and die.