Question

Question #02ced

Answer 1

I got 4:

Explanation:

I tried this:

The rifling of the barrel of the gun caused the projectile to spin around its longitudinal axis and in doing so to be more stable in flight increasing accuracy and precision.
Ironclads were basically armoured artillery pontoons that could be used to patrol and interdict a river or a section of the coast.
Gatling machineguns were rotating multi-barelled machineguns.
The confederates used (more or less succesfully) the submarine to attack a ship. The submarine H. L. Hunley succesfully attacked and sunk the USS Housatonic but it was lost during the operation.