This excerpt taken from the TOO 20-F filed Apr 11, 2008.
Vessel Operating Expenses. Under all types of charters except for bareboat charters, the shipowner is responsible for vessel operating expenses, which include crewing, repairs and maintenance, insurance, stores, lube oils and communication expenses. The two largest components of our vessel operating expenses are crews and repairs and maintenance.
Expenses for repairs and maintenance tend to fluctuate from period to period because most repairs and maintenance typically occur during periodic drydockings. Please read “Drydocking” below. We expect these expenses to increase as the fleet matures and expands, particularly to the extent we acquire vessels directly through our wholly owned subsidiaries rather than through OPCO.