Greg Brooks of Sub Sea Research said a wreck 50 miles (80 kilometers) off the coast of Massachusetts is that of the Port Nicholson, a British vessel that was torpedoed by a German U-boat in 1942. He said he and his crew identified the hull number using an underwater camera.
Salvage operations should begin this month or in early March, he said.
"I'm going to get it, one way or another, even if I have to lift the ship out of the water," Brooks said.
Brooks said the Port Nicholson was going from Nova Scotia to New York and carrying 71 tons of platinum when it was torpedoed. The platinum was intended as payment from the Soviet Union to the United States, he said.
A federal court judge has granted him the salvage rights, he said.
Brooks has been in the shipwreck business for nearly 20 years.