Manitowoc Co. Inc. reportedly signed an agreement to buy private shipyard operator Marinette Marine Corp. for about $48 million cash. The deal is expected to add to about 5 to 10 cents a share to 2001 earnings, said chief financial officer Glen Tellock. The final price will be subject to closing balance sheet adjustments. The transaction, expected to close within 30 days pending regulatory approvals, will be financed with an existing credit facility. "Marinette Marine is one of the most efficient builders of mid-sized commercial, research, and military vessels in the country and will be a key strategic fit with the industry-leading inspection…