Uh, not exactly manufactured in the North. The torpedo makes in the west used anything they could get their hands on as floats and powder chambers. Even glass demi-johns. Torpedoes were a lot more common in the Trans-Mississippi than usually realized. The problem was where to put them. The optimum spots were area of slow water and minimum changes in water level. The Red River was kind of marginal for torpedo operations, higher current, big swings in water level and a lot of debris which might set them off or put them adrift. The torpedo that damaged the Eastport was part of a line of fresh torpedoes that had only been in the water for a few days. There were also expeditions to place them in the Mississippi to bushwack the river patrols. One of the advantages of the teche and atchafalya was the sediment in the water. It blocked vision and made it more difficult to find the torpedoes. One of E.W. Fuller's slaves who had been serving on the Cotton deserted and gave the Union gunboat crews the location of several of the torpedoes.