How much damage does a nuke do exactly?

[Ghost_Ship_Supreme]

Trying to do missiles mission, so I need to know how many salvos I need to hit the blimp with before I can just nuke it

[GgWw1175]

Tested with cheat engine.
The damage seems to scale slightly with proximity—not sure how exactly, because the nuke hits multiple times, and each hit deals pretty inconsistent damage. I've had it deal 548 in total up close, and 538 to an enemy off the screen.
If there's no random variation beyond this, three full salvos should be more than enough, excluding any contact damage you might deal by ramming (missiles deal 6 damage each, and the blimp has 600 health).

[Viking Mana]

How do missiles even work? Whenever I try to use them, they just nose-down toward the sea as soon as they are released.

Edit: I have since progressed to the mission where you have to take down the blimp and learned that they are apparently designed to be non-functional? Even at point blank range, with the Blimp being the only target on your screen, they will immediately U-turn away from it as if repelled by an opposing magnetic force, flying off in random directions toward whatever low-priority target they've locked on to off the screen. Hitting it with a single salvo, let alone 3-4, is borderline impossible to do in any consistent fashion.

And if you don't use the nuke, you have to land around 100 of these? Geez.