William Barker Cushing

Type 95 torpedo, aka Long Lance; best (and deadliest torpedo of WWII).

The problem of how to sink an enemy ship from a distance, without having to approach and ram it with a forward spike (or spike with explosive tip) as early submarines often had to.

The CSS David was a different type of warship. It was semi-submersible. The David would submerge until its deck was hidden. Only the hatchway and smokestack was above the waterline. The idea behind this weapon was to ram a torpedo at a Union ship then back away to avoid the torpedo explosion.

Red Torpedo was created in 2009.