Boston Carriers Inc. (fka BSTN)

[Vector93]

"Spot (voyage) is a charter for a particular vessel to move a single cargo between specified loading port(s) and discharge port(s) in the immediate future. Contract rate (spot rate) covers total operating expenses, i.e., bunkers, port charges, canal tolls, crew's wages and food, insurance and repairs."

http://www.thefreightforwardingcompany.com/glossary/spot-voyage.html

So spot voyage just means they're doing 1-off shipments from one place to another and picking up the need when it's not worth a larger shipping company to do so.

Everything should be covered in the contract though, so there should be no eating into profits to cover costs of repairs, fuel, crew salary, etc.