NEW YORK (Bloomberg) - Excel Maritime Carriers Ltd., which is buying rival Quintana Maritime Ltd. for $2.45 billion, said fourth-quarter profit more than tripled on higher rates for shipments of iron ore and coal.

Net income advanced to $34.1 million, or $1.71 a share, from $9.34 million, or 47 cents, a year earlier, Hamilton, Bermuda-based Excel said in a statement. The average of six analyst estimates compiled by Bloomberg was $1.48 a share. Sales gained 73 percent to $60.7 million.

Excel, which agreed in January to buy Quintana, is increasing the size of its fleet to take advantage of rising demand from China for raw materials including coal, iron ore, steel and grains. The Baltic Dry Index, a measure of shipping costs, more than doubled in the quarter from a year earlier.

"The fourth quarter was very strong," said Natasha Boyden, an analyst at Cantor Fitzgerald LP in New York, who rates the stock "Buy" and does not own any. "Excel has 50 percent of its fleet on the spot market, and they benefited significantly from the strong market."

Excel released its earnings after the close of regular stock market trading. The company fell $2.61, or 9.5 percent, to $24.76 at 4 p.m. on the New York Stock Exchange. The shares have risen 55 percent from a year ago.

Net income included a loss of $200,000, or one cent a share, on interest-rate swaps.

Shipbroker Galbraith's estimated China will increase steel output by about 50 million tons this year, which will mean more imports of iron ore and coking coal, used in steelmaking. China is the world's biggest steel producer.

Chinese demand may also trigger an increase in shipments of steam coal, used to generate electricity, Galbraith's said in a February 22 report.

Global demand for iron ore will advance 6.9 percent this year, Merrill Lynch & Co. said in a February 28 report.

Excel ships earned an average daily rate of $38,539, an 85 percent increase from a year earlier.

The purchase of Greece-based Quintana will more than triple Excel's fleet size.

The acquisition also lowers the average age of Excel's fleet, which usually brings higher rates, and increases the number of ships Excel will have on the time- charter market. The combined company will operate 55 ships with a capacity of almost 5.2 million dead-weight tonnes.

The transaction may close next month. Excel secured $1.4 billion in financing for the purchase.