Mission 108 - Kill "Uncle" Lou Marcano
Buckle up, it's going to be wild ride. You'll want to bring an accurate pistol, and your favorite secondary weapon, but leave the sniper rifles behind. Also, don't worry too much about silencers.
Meet with Donovan and drive out to the site. Take out the guards at the coal dumper and wire the charges, then follow the objective marker to blow them- you don't have to wait for the ship to actually appear or anything, it's all handled in the cutscene.
When the cutscene ends, swim to the ladder on the ship. There are gators in these waters, and they don't appear on the minimap, so swim fast.
Once on board, go north and grab the tacvest if you didn't bring your own (or if the gators got it), then follow the marker to the gaming floor. Ton of baddies and civvies in here. You'll want to save explosives for later, so take position by one of the rear doors and start picking off goons.
A general note for fights on board ship- the shaking will sometimes throw off your aim, or even knock you from cover. Be prepared to adapt. Also be aware that the shaking somehow continuously alerts enemies to your presence, so be prepared for a lot of shoot-outs. Once you've cleared the near area, use the table and pillars as cover to advance up the stairs to the bar. Use Intel View often to keep from being flanked- there aren't quite as many enemies on the boat as there were in the Barclay Mills quarry, but it's damn close. Round the bar, then back up the outside aisle.
Minor resistance taking cover along the benches here, then up the stairs to fight at an outside bar. The enemy weapons here pack a punch, and there's a good number of enemies, so don't get impatient. Pick your shots and work your way round.
Continue following your objective marker, picking up health and supplies as you pass them, until you get to the theatre, through a double set of double doors. This is the toughest fight in the boat, and maybe in the game so far. Lots of enemies, lots of shaking, and the bad guys have grenades.
Best bet is to clear the room in sections- you can't take cover outside the doors because of their weird shape, so just hang back and take out guards that wander into the front of the room. When they're gone, rush to the central table and pick off anyone who shows their face. Prioritize the sniper on the catwalk over the stage, who can repeatedly ruin your whole day.
When the carnage is finally over, climb the onstage ladder and open the door for another cutscene. You'll eventually find yourself with only your knife, limping after Lou as he hobbles away, taking pot shots at you.
There's plenty of cover, but your main strategy should be zig-zagging slightly away from his shots. Actually ducking into cover takes too much time, and you want to catch him before he reaches his destination. Just bob and weave until you're close enough, but oddly use [E] rather than [Q] to perform your takedown. Once that's all over with, it's time to decide on leadership for the French Ward. This is one of the toughest districts to call- it's a plum operation, and each of the bosses can bring something special to the picture. But at the end of the day, Burke's vast experience with Dionysian excess seem the best match, and it is right on his doorstep. Hand him the keys and move on.