How the Barge Shipping Market Works ($CNRD)

This is from the American Commercial Lines 10-K. They are primarily a shipper, but have a bargebuilding subsidiary Jeffboat, which is reporting strong demand for barges.

We have many long-standing customer relationships, including Cargill, Inc., Nucor Steel, North American Salt Company, Shell Chemical Company/Shell Trading Company, Styrolution America LLC, Celtic Marine, Alcoa, Inc. Archer Daniels Midland Co. and Consolidated Grain & Barge Company. [...] In 2012, we anticipate that approximately 60% to 70% of our barging revenue will be derived from customer contracts that vary in duration, but generally are one year to four years in length. The average contract maturity is approximately two years. Most of our multi-year contracts are set at a fixed price, with rate adjustment provisions for fuel, which increases stability of the contract margins. While fuel comprises a significant percentage of our expenses in the transportation segment, generally our term contracts contain provisions that allow us to pass through (effectively on approximately a 45-day delay basis) a significant portion of any fuel expense increase to our customers, thereby reducing our fuel price risk. Furthermore, 58.3% of our term contracts have a general inflation provision based on changes in the Consumer Price Index and 45.6% of our term contracts enable us to pass through increases in our pay scale of vessel personnel.
Generally, contracts that are less than one year are priced at the time of execution, which we refer to as the spot market. All of our grain freight has been priced in the spot market for the past seven years. In 2011 the transportation segment generated approximately 72% of its revenues under term contracts and spot market arrangements with customers to transport cargoes on a per ton basis from an origin point to a destination point along the Inland Waterways on our barges, pushed primarily by our towboats. These contracts are referred to as affreightment contracts.