I understand that Rains and Courtenay and others were making and improving coal torpedoes and other explosive devices. My interest is in records of how and when they were acquired by the United States and other anti-Confederates - or if the Union coal torpedoes were developed in parallel with the Secession examples. Since a knowledgeable Confederate veteran described their use against Confederate and Anglo-Confederate ships, Northerners had to either develop or adapt the technology. It would be interestng to know which.