As in a melee, AD based champion with no actual gapcloser, but a lot of soft CC, i recommend playing Gangplank as a tanky DPS. Not a complete carry but not a complete tank either. This build and guide gives early game sustainability in lane while also granting damage output. I recommend using this Gangplank build when solo-topping and it also works in jungle.
Because gangplank scales well from AD, taking some AD from runes and masteries is recommended. To counter armor runes and items a little bit i also recommend taking some armor penetration for the the whole game. Armor seals and magic resist per level quints are for the lane sustainability and are quite useful in the endgame.
I use 21/0/9 build, to get biggest damage increase and the jungle buff duration for the overall usefulness. The damage increases your potential in lane and the utility part improves the mid- and the endgame.
As i mentoined before, this is a tanky DPS Gangplank build.
Because auto-attacks are the usually the biggest damage you'll encounter in top lane, and junglers are highly physical damage adapted too (Fiddlesticks is another thing), cloth armor + 5 Health potions is a useful combination for the early laning phase.
During the laning phase wards and potions, as usual, are recommended. Continuing the actual build, build Wriggle's Lantern, for defensive, offensive and sustainability stats and you save a lot of money off wards in the laning phase and midgame + early endgame. Also, build Mercury's treads. Even if your W is at cooldown, you're not completely helpless against long duration hard CC. Mercury treads also give the magic resist for the mid- and endgame, which you'll be probably needing later on. (Note. If you're going to lose your lane in the earlygame, philosopher's stone is recommended for sustainability, makes the farming easier if you can't go in melee range to lasthits and you'll get some extra gold you'll miss without it)
When the laning phase is about to end and off-lane roaming turns into a common behaviour, to boost your damage output, build sheen and phage. You'll need those for trinity force later on, and you'll get the damage you need for the midgame. Phage, because your Q can proc the slow, it boosts your overall damage and your survivability. Sheen, because it raises your small manapool, increases your Ultimate's damage and W's heal in a pinch, and it's proc is actually pretty handy with your skills. For example, when you start casting your Q, sheen procs. When it lands, it consumes the sheen proc and boosts the damage.
If you're building a tanky DPS, you better not forget the tanky part. In the midgame, mages and carries get stronger due heavy AP and AD items, i recommend taking classic "Atmogs build". Warmog's is really useful with Gangplank, as he is a good farmer. The stacks will be full in no time, and you can snatch some assists with your ultimate to get even more stacks. Atma's is overall a good choice for gangplank. It boosts defensivity, has that optimal critical strike chance and with the full build, your hp will be pretty high.
When the endgame draws near, you should finish your trinity force from the phage and sheen you bought before. Trinity force doesn't have a stat that you wouldn't utilize as GP. The second item in late-midgame and early endgame, is banshee's veil. It makes you even more resistant to cc, and it boosts your defensive and offensive stats.
When you have enough gold, you should sell your last midgame item, Wriggle's Lantern and buy an Infinity Edge, to boost your damage output. At this point, you deal quite a lot of damage and you can take in a lot of damage before going down. Like other tanky DPS champions, Gangplank has good sustainability in damage and due to his tenacity, W and Banshee, He can be continuously in the melee range of even the furthest targets.
Your passive is Grog-soaked blade. It is a simple on-hit DoT and slow which stacks to 3, with maximum of 21% slow. It's actually really useful if you try to prevent your enemies from escaping.
To get second auto-attack with low cooldown and some extra gold, I recommend taking Parrrley at level 1. It can also help the jungler in pulling if you have a melee based champion in mid and you're the blue team (For example, master yi). Parrrley should be leveled as second priority, because it's mana cost increases quite a lot and it only get 25 extra damage per rank. With this build, you won't have any crit chance at low levels, so you can't count on random Parrrley criticals. When you're farming alone, you should use this ability to take the final hits, for some extra gold gain. Gangplank's build is expensive, you want all the gold you can get. When laning, you should compare, is harassing worth the mana or not. Parrrley turns out to be pretty expensive in the earlygame if used too often. If you're losing your lane, don't bother to harass and get as much gold as you can. Parrrley also procs all on-hit effects, including your passive.
Remove Scurvy, Aka Oranges is your sort-of-unique ability. It heals you a little bit and removes all crowd control abilities. Silences, blinds, slows, roots, taunts, suppressions, basically everything that causes your abilities or movement to disfunction. It has a long cooldown, so don't waste it in Riven's Ki Burst or other mini cc's. Also if you are standing, for example, in Singed's Mega Adhesive, oranges remove the 0,5 sec slow it causes, but it reapplies quickly. You should always priorize Suppressions (Although, it won't stop Urgot from teleporting you), and if more than one cc is used on you at the same time, it removes them both. Make this ability as annoying to the enemy team and as useful for yourself as possible.
Raise Morale is taken at level 2 and it's ranked to 5 at level 9. Passively it gives great mobility and AD boost, which scales 1 to 1 to your Parrrley. At rank 5 with Boots of Speed, you'll be really hard to hit with skillshots. When you initiate a battle, or the enemy initiates, Activate this ability to get damage advantage and more mobility to escape or chace, whichever is more important. When you active the ability, it increases the attack damage and mobility of nearby friendly units also, which increases the potential of ganks in the laning phase. In mid- and lategame, Always pop this when killing baron or dragon, or whenever a teamfight starts. You can use this ability to make faster initiates, or help yourself and other teammates to escape easier, if necessary. Remember, activating this also procs the Sheen/Triforce.
Cannon Barrage is your ultimate. It marks target area, where enemy units are slowed and cannonballs randomly drop in to deal magic damage. It has global range, so in laning phase you can use it to assist teammates in other lanes, as you can make it useful in your own lane. In the midgame you should push some lanes, that you've left alone and enemy creeps are pushing it to your tower. This has saved a lot of towers. Your ultimate can also be used in creative ways. To help your teammates escape, to prevent enemies escape, to block some paths in jungle and simply doing damage and slowing your enemies in large area. Even though it doesn't seem to do a lot of damage, it actually does, if you manage to keep someone in it even for half the duration. It has a long cooldown, so think carefully before using it. If there is a stench of teamfight in the air by dragon, don't bother pushing top lane if there is 8 creeps at opponent's second tower. Cannon barrage also reveals the area, where it deals damage. It can be used to give vision to baron, but make sure that your opponent's are already there, so you won't waste it.
I use flash as my prior summoner spell. Jumping over walls and getting that element of surprise will always be helpful. Ghost is also really useful for GP to get your passive easier applied and it makes initiating and escaping easier.
I use exhaust in top lane as my second summoner spell. It gives you one kind of element of surprise, and it makes the opponent easier to gank, and you can escape easier if necessary. Because you have the advantage in mobility due to your E, you can quickly get in melee range and pop exhaust for maximum damage advantage.
In jungling, the build is actually the same. The only difference is, that your early skill order is E->W->E->Q and you take smite instead of exhaust.
Route to 4: Wolves -> Blue -> Wraiths -> Wolves -> Red -> Wraiths : Lv 4.
When jungling with blue, use your skills as much as you like to spam them. If you don't have blue, clear the minion camps with E. Don't waste your gank potential by emptying your mana pool. E costs quite few mana, and it increases your damage output the largest amount of your skills in the early and midgame.
Red buff is extremely useful for GP in jungle, because your Q procs it with your passive, and when you get phage, you get the random extra slow chance to your Q.
When ganking, Use your E just as you initiate. It gives the laners extra potential to get kills and profit, and it makes your approach easier. Use your Q as soon as possible to get your passive in. Save your W if you are stunned or exhausted, it makes getting kills way easier. If you're over level 6, Pop your ulti just as you initiate and position it just behind your enemies. If they flee through your ulti, they get extra damage income and are slowed, which makes the ganking even easier.