When you reach the cargo, investigate the axles, open the back and investigate the cargo. The first missing box is inside the container, but jammed. The second box is outside. Leave the container and dive straight ahead. You should quickly see the circle indicating an interaction.
Pick up the box that is outside and put it to the others inside the container. Treasure #5 is nearby.
Next you need to go outside, wait for the hooks to arrive and hook up the trailer. You have two hooks and two axles. So one hook for one axle. The trailer will be lifted and you can get the second box. Put it to the others. Then interact with the Sling to be pulled up to the surface.
- 1 -
#3 Antique Padlock
In the first section of the dive, under a tree log.
- 2 -
#4 Chiriqui Shark Trinket
At the beginning of the chapter under water, there is a little cave on the left. It's before you reach the cargo.
- 3 -
#5 Antique Pocketwatch
In the lower area of the dive, where the trailer is.
- 4 -
#6 Antique Arcade Token
On board of the salvage ship. In a storage rack.