(2) Reaching the Belltower's port Deus Ex: HR Guide

Head north and then turn west #1. I definitely recommend staying in this area and making some supplies - a trader named Lu Pin Rong #2 is the best choice. First of all get rid of unneeded items from your inventory, because you won't be able to do this for a long time. You should also buy items which fit best to your game tactics.

Restart exploring the sewers, crouching and entering a nearby tunnel #1. Go through it and after a few moments you'll reach a ladder leading to the surface #2. Using the ladder will let you get near the port.