At the Gallows - Help needed under Vanguard

[Redstart]

I'm stuck in the Vanguard sewers. I've found three levers, one of which doesn't work, and one key on a dead sewer worker. Apparently there's supposed to be a boat somewhere, but so far no luck finding it. Any help?

[Prince of Kitties]

There's a boat in the north, but the canal has been drained there. IIRC the key gives you access to a small room with a drainage control lever, which lets you flood the canal so you can use the boat.

[Redstart]

Do I need to enter the sewers from a different point? Because I've tried every possible combination of the three flood gate levers, and can't seem to make any progress.

[Prince of Kitties]

Have you found the boat? There's a portcullis blocking the water from entering that area, but a little to the east of the portcullis (southeast of the boat) there's a room with a lever - that's the one you want.