By Jad Mouawad and Martin Fackler A global shortage of ships used for deepwater offshore drilling promises to impede any rapid turnaround in oil exploration and supply, thwarting efforts to find new sources of energy and ease prices.

By Jad Mouawad and Martin Fackler As President George W. Bush considers repealing a ban on drilling off most of the coast of the United States, a shortage of ships used for such drilling promises to impede any rapid turnaround in oil exploration.