Cargo

From Deepolis Wiki

On the bottom right of the Game Map you can see your Cargo bay. The different Subs have different size cargo bays. How large your Sub's cargo bay is can be seen on the bottom right, and on the bottom left is a number indicating how much Cargo you already have. Cargo or other items can be found floating around the ocean in containers. To get these items into your Cargo bay, you click on the container and collect them. Raw materials are pieces of wreckage from destroyed subs and NPCs which can also be collected by clicking on them.

There are also other commodities which can be bought and sold at the various underwater stations.