Container ships tend to be fairly slow to respond and may not function as expected during a nuclear war.
The only way for this to work as a retaliatory measure is to have the weapons already in place at the target locations. Now, imagine if someone were to discover the weapon and trace it back to whomever installed it. This is effectively a slow motion nuclear exchange that was initiated by the "defender".
Container ships tend to be fairly slow to respond and may not function as expected during a nuclear war.
The only way for this to work as a retaliatory measure is to have the weapons already in place at the target locations. Now, imagine if someone were to discover the weapon and trace it back to whomever installed it. This is effectively a slow motion nuclear exchange that was initiated by the "defender".