Charter Hire Expenses
Charter hire expenses for the vessels chartered in from third parties were $16.0 million and $10.8 million for the nine months ended December 31, 2022 and 2021, respectively. The increase of $5.2 million, or 47.5%, was mainly caused by an increase in the number of chartered-in days from 399 for the nine months ended December 31, 2021 to 550 for the nine months ended December 31, 2022.
Vessel Operating Expenses
Vessel operating expenses were $52.5 million during the nine months ended December 31, 2022, or $9,553 per vessel per calendar day, which is calculated by dividing vessel operating expenses by calendar days for the relevant time-period for the technically-managed vessels that were in our fleet. The decrease of $4.4 million, or 7.7% from $56.9 million for the nine months ended December 31, 2021 was due to a reduction of calendar days for our fleet from 5,935 during the nine months ended December 31, 2021 to 5,500 during the nine months ended December 31, 2022, driven by the sales of Captain Markos NL and Captain Nicholas ML prior to the nine months ended December 31, 2022. On a per vessel per calendar day basis, vessel operating expenses were relatively flat, slightly decreasing $37 per vessel per calendar day, from $9,590 for the nine months ended December 31, 2021 to $9,553 per vessel per calendar day for the nine months ended December 31, 2022. The slight reduction was primarily the result of a decrease of $154 per vessel per calendar day in operating expenses related to repairs and maintenance, and spares and stores, partially offset by an increase of $134 per vessel per calendar day in operating expenses related to lubricants.
General and Administrative Expenses
General and administrative expenses were $24.5 million for the nine months ended December 31, 2022, an increase of $1.2 million, or 5.5%, from $23.3 million for the nine months ended December 31, 2021. This increase was driven by $0.8 million in financial support for the families of our Ukrainian and Russian seafarers affected by the events in Ukraine and increases of $0.8 million and $0.7 million in stock-based compensation and other general and administrative expenses, respectively, for the nine months ended December 31, 2022. This was partially offset by a reduction in employee-related expenses of $1.1 million for the nine months ended December 31, 2022.
Interest and Finance Costs
Interest and finance costs amounted to $28.6 million for the nine months ended December 31, 2022, an increase of $10.0 million, or 53.6%, from $18.6 million for the nine months ended December 31, 2021. The increase of $10.0 million during this period was mainly due to increases of (1) $8.0 million in interest incurred on our long-term debt, (2) $2.0 million in accelerated amortization of financing costs resulting from the repayment of the 2015 AR Facility and long-term debt on Concorde and Corvette, (3) $1.0 million in loan expenses driven by increases in average interest rates on our long-term debt due to rising SOFR on our floating-rate long-term debt, and $0.9 million in capitalized interest. The increase in interest on our long-term debt was driven by an increase in average interest rates due to rising SOFR on our floating-rate long-term debt, and an increase in average indebtedness, excluding deferred financing fees, from $587.7 million for the nine months ended December 31, 2021 to $663.6 million for the nine months ended December 31, 2022, driven by the 2022 Debt Facility refinancing during the nine months ended December 31, 2022. As of December 31, 2022, the outstanding balance of our long-term debt, net of deferred financing fees of $6.3 million, was $629.3 million.
Unrealized Gain on Derivatives
Unrealized gain on derivatives amounted to $4.8 million for the nine months ended December 31, 2022, compared to $4.2 million for the nine months ended December 31, 2021. The $0.6 million difference is primarily attributable to favorable changes in forward SOFR yield curves (forward LIBOR curves in the prior period).
Realized Gain/(Loss) on Derivatives
Realized gain on derivatives amounted to $2.0 million for the nine months ended December 31, 2022, compared to a realized loss of $2.7 million for the nine months ended December 31, 2021. The favorable $4.7 million difference is due to an increase in floating SOFR resulting in the realized gain on our interest rate swaps.