You begin underwater in this chapter. First let's do some optional treasure hunting.
From your starting position you see a large rock slightly up ahead. Swim past its right side and curve a little to the right. Underneath the tree trunk that is lying on two rocks you can find treasure #3, the [ANTIQUE PADLOCK]. Continue straight ahead and you'll notice two tunnel-like openings in the distance. Move through the hole to the right and you should be able to spot treasure #4 already inside, the [CHIRIQUI SHARK TRINKET].
Head out and follow the river. You can find a piece of iron among the sea grass. Simply continue to find the container you're looking for. Before going in, first collect treasure #5. Facing the container, turn to the right and move all the way to the end to find the [ANTIQUE POCKETWATCH] at the rock wall - look for the glimmer.
Go back to the container and look through the crack, then open it up and inspect the cargo crates. Turn around to find one crate stuck underneath the container. The second crate is (when you come out of the container) a little bit to the right - it should be marked. Pick it up and place it with the others, then exit the container. Grab the two cables and swim around the wheels underneath the container to make them stick.
When it has been lifted up, search underneath it to find the second crate and place it with the rest. Get in position on the lift to go up.
Drop down and look to your right to spot a few colleages unloading the cargo; here is [OPTIONAL CONVERSATION #1]. Head up the steps and speak with the salvage worker to the left for [OPTIONAL CONVERSATION #2]. Better yet, turn around and check out the nearby cabinet to find treasure #6, the [ANTIQUE ARCADE TOKEN].
Now that you're done exploring, speak with Jameson in the back, who's speaking with another salvage worker, to conclude the chapter.