This is not some backyard slang for anything it is sailor talk for the Supply Officer. He is the person who oversees the entire supply section of the ship. His department is responsible for everything the ship needs to operate. This includes all of the spare parts the engineers need right down to the tooth paste sold in the ships store.

If you think the ship might need it this guy is the one who makes sure the ship has it. Every department will have there own supply person, but 100% of everything ordered is passed on by Suppo.

His group takes care of the ships store which in turn supplies the sailors with those things they just cannot live without, soap, tooth paste, socks, underwear, and geedunk. Also when traveling to unique location they will provide some of the local flare onboard so even those sailors who were on restriction can buy something from Norway or Spain, or wherever.

A good deal of time in port it seems the supply department does not do all that much. Heck even underway they seem to be taking it easy, but without them around there would be nothing to keep the ship moving. Your current work place has a SUPPO, but he/she is known as the purchasing agent.