In potco I remember trips where I took home 8K gold.
I think the way they have it working right now is you take home mats/loot chests and the gear that those replaced. So say you started hunters with 27 cargo, including 2 skull chests and 4 loot chests. Those 6 containers can't be replaced by mat chests. The other 21 you'll get paired up with the mat chests. By the end of the run, these are usually just royal chests and loot pouches I believe.
Unless I'm mistaken, the ranking order of loot is:
-skull chests (I know this for good because once I sunk a warship for last cargo, it gave skull instead of rare material)
-loot chest
-rare material
-material
-royal chest
-loot pouch
-treasure chest
-cargo crate
When you get a full hold, any loot that is higher on this scale will replace anything below it. I'm not positive, but I think in POTCO, they put everything but skull chest BELOW the loot, especially materials. Point being that instead of getting a lot of loot, we got to keep the royal chests and treasure chests and even cargo crates-which give gold-before keeping loot. Crates may have been the one out; I do remember getting loot there, but the basis of my claim is that POTCO gave more emphasis to gold on sailing runs, whereas TLOPO they put loot first. In order to get gold here, we have to get lucky and have a fair amount of gold in the loot, or have royal chests replacing the loot pouches while we're hunting.