(Edited due to oversights and ridiculous numbers) So I was curious about this. I know similar questions have been asked but they all have specific parameters that are different from mine.

All ships are equipped with dark matter engines, allowing them to accelerate faster then what should be possible given the limitations of the human body, at around 2500gs for sublight when all power is to the engines, and around 250gs of acceleration when combat systems are being used. There are also maneuvering thrusters with a max of around 200gs accelerationfor them.

So basically all ships are equipped with laser weapons no matter the size. The power will differ but they all have lasers. 2: smaller ships (gunships, corvettes) will have mass drivers that fire rounds at about .3c. Larger ships like destroyers and cruisers (apart from heavy cruisers) use Railguns that fire rounds at around 2200gs Heavy cruisers, carriers and Battleships will use Gauss cannons to fire rounds at about 2500gs

Small ships will have kinetic and energy point defense weapons. Kinetic ones fire rounds at 1300gs

Large ships will have heavy autocannons and converted mass drivers as point defenses along with energy weapons. Autocannons fire at 1500gs base velocity and mass drivers at 2000gs

All ships have some form of torpedo, most ships use torpedoes that have a base acceleration of around 2100gs and a burnout time of 3 minutes. They are radar guided. Carriers and battleships will often use larger warheads that have an acceleration of 2500gs and a burnout time of 3.5 minutes

Carriers carry gunships and corvettes, along with landing craft. Ship armor and shields is normally good enough especially for larger ships that engagements can be drawn out, for smaller ships capital class weapons will usually destroy them relatively fast. All targeting is done with AI, target acquisition and the discharging of weapons is done by humans but tracking and leading is done by targeting AI most of the time. Some ships have their whole weapon system completely controlled by AI while others split the responsibility. I’m also curious about how they would fare against more.... realistic ships IE ships that are less advanced, IE more realistic ships that are bounded by basic physics and human biology (can’t accelerate too fast, stuff like that) assuming that things like shielding and armor stay consistent for simplicity.

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    $\begingroup$ If ships can accelerate at 1800G in combat then torpedoes that can only accelerate at 800-850G (once metres per second squared are approximated to G) are not very useful. You may want to check your units and edit the question. $\endgroup$ Jun 21, 2021 at 1:16
  • $\begingroup$ Just want to add this comment saying I fucked up bad, did the engines after the weapons systems because well.... I forgot about them so I didn’t realize the values I had. I redid the values and hopefully it’s better now. My bad $\endgroup$ Jun 21, 2021 at 2:12
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    $\begingroup$ You're listing autocannons and railguns in gravities, which makes no sense. A standard gravity is a unit of acceleration, not velocity, and "muzzle" velocity is what matters for weapons, not how fast the round gets to that velocity. $\endgroup$
    – jdunlop
    Jun 21, 2021 at 2:16
  • $\begingroup$ Do your torpedoes have guidance beyond burnout, or are they just ballistic at that point? What sort of lateral thrust can they produce, and how much of it? This makes a big difference in how close you need to be. $\endgroup$
    – throx
    Jun 21, 2021 at 5:01
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    $\begingroup$ Also, related: worldbuilding.stackexchange.com/questions/193909/… $\endgroup$
    – throx
    Jun 21, 2021 at 5:13

1 Answer 1


Let's assume, for convenience, that the diameter of the laser is about the diameter of the target ship. If ships of any type can perform evasive maneuvers at, say, 2000 gravities, then the distance at which a weapon can reasonably reliably hit is the distance at which the travel time of the weapon to the target ship is less than than the time it takes for the target ship to move one ship-length. At longer distances, the ship has enough time to move out of the way of the beam by randomly accelerating / decelerating.

So, at 2000 g (19,620 m/s²) a ship would move about 98.1 meters in 0.10 sec. and about 220.8 meters in 0.15 sec. since acceleration compounds. (For comparison, an Iowa class battleship used in WW2 is about 270 meters long.) A laser beam moves at the speed of light, unsurprisingly, so your engagement distance for lasers might only be at around ~0.15 light second, which is about 45,000 kilometers. The solid projectile weapons (railguns, autocannon, mass drivers, etc.) fare even more poorly since their projectiles are much, much slower and have a much smaller size than the laser beam, they are easier to dodge.

(But wait, you say, what if I make the laser's beam width bigger? Well, that increases the chances of hitting the target but also weakens the beam since its energy is spread out over a larger area. How much? Quite a lot; good ol' πr² tells us that if you double the diameter of the beam, you get 1/4 the intensity and if you triple the diameter of the beam, the beam is at 1/9th the intensity.)

The torpedoes simply have no effect except at point blank range. 2000 g is, as mentioned earlier, about 19,620 m/s², so any ship easily outruns the acceleration of the 8,500 m/s² torpedoes.

  • $\begingroup$ Are you suggesting all ships are always jinking randomly at maximum thrust to move out of the way of potential lasers (axiomatically, you can't see a laser coming because nothing is faster than light)? It's possible, I guess, but you're turning your odds of hitting into a Monte Carlo simulation where both sides are firing/moving randomly. $\endgroup$
    – throx
    Jun 21, 2021 at 5:05
  • $\begingroup$ @throx Even if they're not maneuvering to evade incoming fire (and there's precedent for that in WW2 era ships maneuvering to evade torpedoes and to make targeting shells on it more difficult), the target ships will be maneuvering to engage their own targets or to perform some other mission, so I think it's reasonable to assume some level of unpredictable motion that needs to be accounted for. $\endgroup$ Jun 21, 2021 at 14:56

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