Voyage Expenses. Voyage expenses were $99.8 million for the nine months ended September 30, 2024, an increase of $1.1 million from $98.7 million for the nine months ended September 30, 2023. The net increase included a $3.5 million increase in port, agency and broker commission costs, partially offset by a $2.4 million decrease from lower bunker prices.
TCE Rate. The average TCE rate for our fleet was $32,821 per day for the nine months ended September 30, 2024, an increase of $3,707 per day from $29,114 per day for the nine months ended September 30, 2023. TCE rates represent net revenues (or revenue less voyage expenses) divided by revenue days. Net revenue utilized to calculate TCE is determined on a discharge-to-discharge basis, which is different from how we record revenue under U.S. GAAP.
Vessel Operating Expenses. Vessel operating expenses were $45.1 million for the nine months ended September 30, 2024, an increase of $0.5 million from $44.6 million for the nine months ended September 30, 2023. The increase reflects the timing of vessel operating expenses between quarters. Vessel operating expenses, by their nature, are prone to fluctuations between periods.
Charter Hire Costs. Total charter hire expenses were $16.9 million for the nine months ended September 30, 2024, an increase of $3.0 million from $13.9 million for the nine months ended September 30, 2023. This increase is as a result of higher charter hire rates during the nine months ended September 30, 2024 compared to the nine months ended September 30, 2023. Total charter hire expenses for the nine months ended September 30, 2024 were comprised of an operating expense component of $8.8 million and a vessel lease expense component of $8.1 million.
Depreciation. Depreciation expense for the nine months ended September 30, 2024 was $22.4 million, an increase of $1.7 million from $20.7 million for the nine months ended September 30, 2023. This increase is primarily attributable to the purchase of the Ardmore Gibraltar in April 2024, and the installation of ballast water treatment and scrubber systems on several vessels during their most recent drydock cycle.
Amortization of Deferred Drydock Expenditures. Amortization of deferred drydock expenditures for the nine months ended September 30, 2024 was $2.7 million, an increase of $0.1 million from $2.6 million for the nine months ended September 30, 2023. The deferred costs of drydockings for a given vessel are amortized on a straight-line basis to the next scheduled drydocking of the vessel.
General and Administrative Expenses: Corporate. Corporate-related general and administrative expenses for the nine months ended September 30, 2024 were $16.6 million, an increase of $1.7 million from $14.9 million for the nine months ended September 30, 2023. This increase was primarily due to one-time expenses associated with the leadership transition during the nine months ended September 2024 compared to the nine months ended September 30, 2023
General and Administrative Expenses: Commercial and Chartering. Commercial and chartering expenses are the expenses attributable to our chartering and commercial operations departments in connection with our spot trading activities. Commercial and chartering expenses for the nine months ended September 30, 2024 were $3.3 million, generally consistent with $3.3 million for the nine months ended September 30, 2023.
Gain on Vessel Sold. Gain on vessel sold for the nine months ended September 30, 2024 was $12.3 million, compared to $0 for the nine months ended September 30, 2023. This relates to the sale of the Ardmore Seafarer in April 2024.
Unrealized losses on Derivatives. We had an insignificant amount of unrealized losses on derivatives for the nine months ended September 30, 2024, as compared to no unrealized gains or losses for the nine months ended September 30, 2023.
Interest Expense and Finance Costs. Interest expense and finance costs for the nine months ended September 30, 2024 were $5.7 million, a decrease of $3.0 million from $8.7 million for the nine months ended September 30, 2023. The decrease in costs was due to the reduction of the average outstanding balance due to the conversion of our term loan into a fully revolving facility, with 50% of the term loan being converted to a revolving facility during the three months ended June 30, 2023, and the remaining 50% being converted during the three months ended March 31, 2024. The current flexibility of our revolving facilities, with only $22.5 million drawn down as of September 30, 2024, has minimized the impact of the elevated interest rate environment. Amortization of deferred finance fees for the nine months ended September 30, 2024 was $0.9 million, consistent with $0.9 million for the nine months ended September 30, 2023.