The worst U.S. drought in more than half a century helped drive down rates for Panamax vessels shipping grains to the lowest in more than 3 1/2 years as it results in a slump in cereal cargoes.

The ships hauling about 60,000 metric tons of grains and other commodities including coal and iron ore slid 5.7 percent to $5,141 a day, the lowest since January 2009, according to data from the Baltic Exchange in London yesterday. The Baltic Dry Index, a wider measure of costs, fell 1.3 percent to 684 points.

Global grain exports will fall the most in 27 years in the 2012-13 marketing year as the drought curbs shipments from the world’s largest supply country, U.S. Department of Agriculture data show. Panamaxes joining the fleet jumped 43 percent in the last two quarters, adding new vessels at the fastest pace since 2001, according data from Macquarie Research and Clarkson Plc.

“Panamax brokers report scarce new cargoes in both the Atlantic and the Pacific,” Fearnley Securities AS, an Oslo- based investment bank, said in an e-mailed note yesterday.

Daily earnings to hire Panamaxes for voyages across the Atlantic Ocean fell the most since Feb. 12, sliding 9.5 percent to $4,153, the lowest since Dec. 18, 2008, exchange data show.

Grains Contraction

The global grain trade will contract 9.1 percent to 289.4 million metric tons in the 2012-13 marketing year, the USDA estimates. That’s the biggest retreat since 1985-86 when it shrank by 18 percent.

The drought affecting the U.S. grain crop will “significantly effect” Panamax vessels and Supramax vessels 25 percent smaller through the autumn harvest, Clarkson (CKN) said in a report distributed last month.

Daily Supramax earnings declined 0.5 percent to $8,834 daily, while average costs for Handysize ships, the smallest tracked by the Baltic Exchange, slid 0.2 percent to $6,623 daily. Capesizes, the largest, mostly shipping iron ore, advanced 0.9 percent to $3,497.

Source: Bloomberg