This is a 15-second, time fuse from the museum's USS Cumberland collection. A member of the ship's company would screw this device into an explosive shell right before the shell was loaded into a gun. The fuse would ignite the powder inside the iron shell, causing it to burst. In theory, the fire caused by the cannon firing would ignite the fuse.
Timed fuses allowed for the shell to penetrate a target's hull before exploding, making it the ideal choice against other ships and against soft targets such as forts constructed out of sand or dirt. The fuse is a mixture of potassium nitrate, sulfur, and black powder with black powder used as a variable. Fuses with shorter denotation times would have more black powder than fuses with longer denotation times.
The Navy tightly controlled the manufacturing and distribution of these small devices. The Navy's ordnance manual made it very clear that no one was to teach unauthorized persons, particularly foreigners, how to assemble a fuse. An ordnance laboratory at the Washington Navy Yard was the sole assembler of the devices. The Navy's ordnance department then distributed the completed fuses to the Government’s other navy yards, who in turn handed them out to deploying ships. Unused or old fuses were to be sent back to the laboratory to be remanufactured, stored, or disposed of.
