Well, let's take a look at that actually.
Assault Ketches look like this.
Two turns each, cannot be built in parallel, cost of 25 NEP for the main guns, I don't know how the subsystems shake into it and I can't find the reference offhand.
Now, here's the War Ketch redesign
Major difference is that we trade out one of the Plasma Thrusters for another Aethersail, and add a Holo-Field and a Grav-Shield. Again, I can't find where the NEP costs for each of these are, but after the first turn tax, every additional one we build in a batch takes another turn it seems, up to a total of 4 started in parallel which takes 4 turns. If anything, the War Ketch should be more costly in NEP, but...
In turns of time effectiveness? The important thing to keep in mind is that once we've started a build, it goes on it's own until it's done. It doesn't eat up extra BAP I don't think aside from the general "Keep the docks running" cost. Every additional War Ketch after the first one is effectively produced at half price in time investment.
Which means that, ideally, if we're not going to be in a life or death war imminently, we want to do as large a batch as we can in any given stretch. Because building 4 Assault Ketches would take us 8 turns if we did them one by one. In contrast, building 4 War Ketches when we did them in a parallel batch costs us 5 turns of time, saving us 15 years despite a War Ketch presumably costing more in everything but Exotics.
Realistically, we don't even want to mass produce War Ketches though, outside of our refits. Because the very incentives that let us parallel-build them means that we need to spend a much larger overlay of material to field them. 350 Starcrystals and 50 Psy-Scopes is nasty but affordable if you're only doing them one at a time.
1,400 Starcrystals and 200 Psy-Scopes on the other hand is almost two turns of production on both exotics, just for a single squadron of escorts! I wouldn't be surprised too if there's a "Fiddliness" penalty involved either, because comparing our Lance Cutters (2 Las Lances, 2 Aethersails) to our Nettles (3x Spike Cannons, Lascannon PD, 2 Aethersails, Holofields), on paper, this should be expensive as fuck compared to Lance Cutters. And it is more expensive.
But not by as much as you'd think.
2 turns to produce a set of 5 Lance Cutters, which are weak, incredibly fragile destroyers with zero self-defense ability beside Going Fast.
2 turns to produce a set of 3 Nettles, which are just as fast, dramatically better armed, carry Point Defense which lets them serve as anti-torpedo and anti-fighter screens for heavier warships, and even have a Holofield to boot! For something that should cost probably close to twice as much on paper, Nettles only seem to actually be 130% the cost of a Lance Cutter, which tells me there's things we don't see yet.
TL;DR: NEP isn't free, but it's a lot cheaper than Exotics, especially when you scale things up to industrial quantities.
