I'll be honest, I'll need to figure out the total market value once I finish making a trade goods sheet. While I'm mostly stealing it from someone else who did most of the hard work for me, it's not quite tailored for 5e, so I need to make specific adjustments for it. A Unit is typically anywhere between 100-500 pounds, as it also depends on the volume it takes up. 100 pounds of iron takes up far less space than 100 pounds of feathers and all that good stuff. As for the ship's initial inventory, it was mainly just food supplies, bedding, and materials to repair the ship. All of that combined would take up roughly 35/100 units of space your ship can hold.