Space is large enough the minefield would need to be overwhelmingly wide, and extensive minefields aren't generally something you place where you want to be able to run normal commercial traffic through regardless, like we would with any of our worlds.
We'd be linking them to command crews in our defence stations; think of them more like "a bunch of cruise missiles I can ask to shoot this target" as opposed to fully-autonomous mines.
Getting 4,000 torpedo tubes of firepower for the price of 100 isn't very useful when only a handful of those mines would be in position to meet the attackers,
This is true of anything, though. An opportunistic attack probably consists of jumping in, fucking around a bit, and then jumping out. Meanwhile, a response to this attack is either detecting the light flashes directly and following a brachistochrone trajectory to respond a few days later, or waiting for a jump messenger to arrive a week late, and then jumping in two weeks after. Against a raiding force that's jumping in, smashing things up, and leaving consists of basically what's situated around the target body, regardless of propulsion capability.
Meanwhile, in the hypothetical case of a planned fleet-on-fleet engagement, the smart decision against a peer enemy not using mines/defensive stations is to split off some light cruisers with a long jump capacity and start jumping into their rear areas and shooting shit up (if you're particularly mean, jump a "boomer" 100D away from some sensitive infrastructure of theirs, salvo off a dozen nuclear land attack torpedoes, and then jump out). This either forces them to accept cities getting bombarded, or to permanently station warships there to defend them against opportunistic raiders, which in turn means your enemy will probably be weaker when it comes to the fleet engagement.
In this sense, mines aren't a strategically "defensive" measure; they're a way of ensuring that we can focus our offensively-useful ships like CFAs on attacking the enemy or responding to long-term incursions while also defending against short-term incursions. They're freeing up mobile units from stationary defensive tasks.
Also, it's not a 40:1 ratio for torpedoes per dollar, but instead about 1200:1.
with only a single shot each;
I was counting the reloads when looking at the CFA-B. If we're just looking at ready-to-fire torpedoes, it's a hundred thousand to eighteen.
The tonnage is better spent on a fleet of normal ships that can guarantee each of their tubes will be able to meet the attackers, coordinate with each other, and fire multiple salvos.
If we have a small defence station that's sending out firing commands to the mines, they'd be able to coordinate targets. The request-for-fire wouldn't be "mine X, fire at this target 300 km from you", but instead "all mines of group A, fire at a target at target at coordinates x, y, z, staggered to simultaneously arrive at time t".
Point defence means multiple salvoes are bad. Ideally we launch just enough to kill the target in a single wave.
