OK guys I'm going to be honest with you this build makes gangplank a HARD carry. if you can get to finishing infinity edge then the rest will be a cake walk. also i know what your saying "deny plank is much better" but this is just how i play gang I've never been one to play deny and its just not my thing, i wont deny that it probably is mad effective its just not the way i play. so sorry. anyways lets move on to the build

summoner spells -
heal & clarity
yeah i know you've probably stop reading saying, dam what a noob this kid is. this build sucks, but the spells aren't just for me its a team game after all.
heal - heals you and anyone around you. well that sounds simple and it is. but to truly use it is another thing all together. early game its to keep sustained pushing and prevent cumulative dmg from poker champs like sona and well gp ;)
mid to late game its to keep your team alive when you dive a tower or same a teammate when he/she is being chased or give your team a hp boost when fighting an aoe combo like galio+kat+amumu which btw sucks to play against
clarity - u need mana or your lane mate needs mana simple enough. also it make for a good bait when you are soloing a side lane an you low on health and mana so they dive you for the kill and you pop this your ult and remove scurvy and proceed to kill them..... awwww good times lol

skills -
get all of them then priority is ult, parrrley, raise moral, and remove scurvy.

runes - simple enough crit chance and mana regen per lvl and then just a but of health to make u not so squishy

now here is where the money lies
items - i found that go is one of the few champs that can go into battle, effectively, without boots. thus this build doesn't have any to optimize his badassness. with the items its more about making it to certain points to pull ahead of the competition. the "break-through" points are.....
1)bf sword
2)infinity edge
3)trinity force
4)blood thirster
the reason its hard getting to these points is because the cost is very high for these weapons and you have no slots to place parts into so u have to save up alot of money for each major purchase but when you do get the items your ahead of the curb thus you must make the most of each "boost stage" as i like to call it

1) vamp scepter - this will keep you alive in the early stages easily just farm thats it
2) av blades - mo money and decent crit chance
3)2x zeal - my the time you finish the second one you will have 380 m.s. and that should be without finishing raise moral. thus you see the point of no boots also when raise is at lvl 5 your m.s will be 395 +or- a couple
4)bf sword
5)cloak of agility -wait for it \/
6)infinity edge - its a crit character no explanation needed
7) sheen or phage - here it depends if your wrecking them get sheen otherwise go phage
8) zeal => trinity - decent dmg, some health/mana, random slowing, and o yeah it doubles your parrrley dmg which end game is 1900+ on minions( is anywhere from 600 on tanky garen to 1700 on squishy viegar)
9)another bf sword
10) vamp => blood thirster - redic dmg and life steal whats not to like
11) cloack of agility
12) zeal => phantom dancer - more crit chance and more ms and dodge and a.s.
13)brut for this \/
14) ave=> ghost blade - cooldown and crit and dmg and the ****ing awesomeness of activiting it for god mode
15) by all the elixirs
16) bf sword
17 blood thirster
so at the end of it all you have 50% lifesteal and 500+ dmg and 440 movespeed and 100% cirt chance
you are a god.
well tell me what you think and
gl&hf