There are a few Gangplank support guides out there already, most of them are putting the mastery points in utility/offense while buying AD items, trying to create some squishy half***ed damage dealer. This guide is focusing on making a strong utility tank that is useful early, mid and late.

By following this guide, you will provide the following things to your team:
Ability to tank, poke (early) and deal global aoe magic damage
Three slows with passive, ultimate and IBG
CC blocking
40 AD, 10% LS and 10% MS from E combined with Zeke's to your teammates
2 shields from Face of the mountain and Locket

The reason for our mighty early game. A 21% slow and a non scaling damage over time effect you don't need to build damage to utilize

The second reason for our strong early game. A ranged boosted AA on a very low cooldown

Extremely important in some matchups, less important in others. Makes Thresh cry

Our main supporting ability mid and late game. AD and MS boost for 7 seconds to nearby teammates

Very strong damage for a support ultimate. A big factor during 2v2 engages in lane, as well as for slowing escaping enemies during ganks, and great for wombo combos later on

Flash Exhaust

The AD marks gives us a decent increase in early poke damage.
Armor seals and quints brings our armor up to above 50 at level 1, helping us greatly in both reducing poke damage, and damage taken while engaging the enemy in melee range.
Mana regen glyphs makes us able to poke with Q more frequently. Q has a very short cooldown, and the ammount of harrass you can do is only limited by your mana.

Start with


Build these first
face of the mountain

Then these
zeke's herald

Make sure you use your Relic shield stacks with Q for bonus gold.

There arent many situational items while playing Gangplank support. These six items will be the optimal build for nearly every game. The exception might be against very AP heavy teams, where you may want to build a Frozen Mallet instead of IBG to get HP instead of armor.

The first 5 levels, our main jobs will be 1: poking, thats why we focus on leveling Q, and 2: blocking CC and keeping our HP up, thats why we level W second.
After level 6, the opposing support has often gotten tankier, while the opposing adc has aquired more lifesteal. This combined with us not building any AD makes spending more points in Q a waste, because it will deal very weak damage even with 5 points in it. This is also the time when teamfights tend to start, which is why we now move focus towards maxing our E buff instead.
At level 13, it doesnt really matter if we max Q or W, because we arent using Q for damage, and we arent using W for healing.

In case a 1v1 situation happens in lane, Gangplank can kill almost any other support, and even a good ammount of ADCs at early levels
Your level 1 engages will be unbeatable by 90% of the enemy compositions
Support Gangplank's ult does the same damage as a full build bruiser/critplank's ult

Demonstrating video of a full game: Play Video http://www.twitch.tv/bigbosskhadgar