The nuclear depth charge proposal that endangered its own ship

What is the least sensible nuclear-weapon idea discussed in this ship-design exchange?

A proposal placed nuclear depth charges on the stern rack of an 18-knot ship, which could not escape the blast after dropping one.

One design proposal treated a nuclear depth charge like an ordinary weapon rolled from a stern rack. The ship's maximum speed was only about eighteen knots. It could not open enough distance before detonation to survive its own attack. The example is a compact lesson in testing a weapon concept against platform speed, delivery geometry, and minimum safe separation rather than evaluating the warhead in isolation.