Post by millesmissiles on Oct 3, 2016 1:24:28 GMT
CIWS is a tricky issue unto itself. Missiles are cheap and at a certain point a ship specced for point-defense will have to do so at the cost of other abilities like fighting other capital ships.
Lasers are out for reasons mentioned above. Basically, armoring a missile against laser fire is relatively easy using silica aerogel. Even if you have a ludicrously powerful laser, you're going to be spending a few precious seconds taking out each missile.
Conventional guns seem to be out, contrary to how the US Navy has been doing CIWS. Muzzle velocities seem to be too low to allow any kind of reasonable standoff range. Anything a conventional gun could do for CIWS, railguns or coilguns could do it better.
Railguns and coilguns seem to be moderately effective. What would be great is some kind of feature to select certain weapons as "point defense", so that they would independently fire on incoming targets. Heavily armoring a missile is prohibitively expensive, as one of the biggest benefits of missiles is their cheapness, and so it shouldn't take many shots/ heavy slugs to take a missile out. If independent targeting was implemented, and you had a sufficient battery of high-velocity guns, you might conceivably take out a great number of missiles. Do note that when railguns are balanced to obey the laws of physics, which will probably be a huge reduction in their rate of fire or how massive a slug they can shoot, their effectiveness as CIWS will be greatly reduced.
Let's assume that your weapons are accurate enough to take out missiles at around 25km. This varies, but missiles are tiny, fast-moving targets and one slug isn't always enough for a kill. Let's also assume that missiles are inbound at 1 kps, so you have 25 seconds of point-defense fire before impact.
A good point-defense railgun might fire 20 shots a second at 10 kps. Current firing mechanics means that weapons fire until their target is destroyed, so you're going to fire for 2.5 seconds before hitting your target. In that time, the missiles have advanced 10% of the way towards your ship. If this fire instantaneously kills the target, the railgun will switch and fire on another missile- now 22.5km distant.
If you're savvy, you'll realize that the missiles will advance 10% of their current range when point-defense goes up before impact. This continues: 25km, 22.5km, 20.25km... As missiles get closer, the travel time of your slugs is decreased and kills can happen faster. At the same time, however, missiles set to "controlled homing" will start maneuvering as they get closer, reducing the kill rate of your point-defense. What this boils down to is that you have a limited number of "bursts" from each point-defense gun, in the range of 10-30 depending on various factors, before impact.
Point-defense is limited by how accurately it can fire and its muzzle-velocity. A faster slug delivered accurately is best. But even firing flak, it's unlikely you'll take out more than a single missile in each "burst"- fragments lose lethality quickly with distance, and missiles can be set to "scatter" to reduce the chances of a multi-kill.
So now we have a situation where a single point-defense gun could confidently take on 10-30 missiles before intercept. It's conceivable that a battery of 10-20 would be enough to protect a ship from large salvos of incoming missiles. This will be limited, of course, by the cost in credits and mass incurred by each gun. For that matter, placement of these guns becomes an issue. Lateral gun batteries require turning the ship to bear, and this HUGELY reduces the effectiveness of armor when/ if those missiles hit you. Mounting them on the bow allows all guns to bear at once but occupies valuable real-estate AND essentially guarantees that you'll lose a great deal of your guns if a few missiles sneak through.
For that matter, missiles sporting a centimeter or two of depleted uranium in the nose will shrug off incoming projectiles, and missiles with faster closing velocities will allow less chances for point-defense fire. This of course makes missiles more costly, somewhat reducing their merit as cheap weapons.
I'm personally a fan of active point-defense. Flak missiles can intercept other flak missiles pretty easily and usually at a 1-1 ratio, and I've yet to build a dedicated anti-missile missile. For those few that sneak through, lasers and anti-capital railguns can usually take them out. I've also been building my ships with 3.5cm of maraging steel in the nose and they can shrug off direct hits from whole salvos flak missiles if taken nose-on- have yet to figure out how to armor a 100 MW laser to survive that, though.
TL;DR railguns and coilguns make alright point-defense but will be severely gimped by Real Physics (tm) when they're nerfed and can still be overwhelmed by large or fast salvos of missiles. Anti-missile missiles can be cheap (think RIM-116 for a real-life example) and plentiful and will probably be the most effective means of dealing with large salvos of missiles.
Lasers are out for reasons mentioned above. Basically, armoring a missile against laser fire is relatively easy using silica aerogel. Even if you have a ludicrously powerful laser, you're going to be spending a few precious seconds taking out each missile.
Conventional guns seem to be out, contrary to how the US Navy has been doing CIWS. Muzzle velocities seem to be too low to allow any kind of reasonable standoff range. Anything a conventional gun could do for CIWS, railguns or coilguns could do it better.
Railguns and coilguns seem to be moderately effective. What would be great is some kind of feature to select certain weapons as "point defense", so that they would independently fire on incoming targets. Heavily armoring a missile is prohibitively expensive, as one of the biggest benefits of missiles is their cheapness, and so it shouldn't take many shots/ heavy slugs to take a missile out. If independent targeting was implemented, and you had a sufficient battery of high-velocity guns, you might conceivably take out a great number of missiles. Do note that when railguns are balanced to obey the laws of physics, which will probably be a huge reduction in their rate of fire or how massive a slug they can shoot, their effectiveness as CIWS will be greatly reduced.
Let's assume that your weapons are accurate enough to take out missiles at around 25km. This varies, but missiles are tiny, fast-moving targets and one slug isn't always enough for a kill. Let's also assume that missiles are inbound at 1 kps, so you have 25 seconds of point-defense fire before impact.
A good point-defense railgun might fire 20 shots a second at 10 kps. Current firing mechanics means that weapons fire until their target is destroyed, so you're going to fire for 2.5 seconds before hitting your target. In that time, the missiles have advanced 10% of the way towards your ship. If this fire instantaneously kills the target, the railgun will switch and fire on another missile- now 22.5km distant.
If you're savvy, you'll realize that the missiles will advance 10% of their current range when point-defense goes up before impact. This continues: 25km, 22.5km, 20.25km... As missiles get closer, the travel time of your slugs is decreased and kills can happen faster. At the same time, however, missiles set to "controlled homing" will start maneuvering as they get closer, reducing the kill rate of your point-defense. What this boils down to is that you have a limited number of "bursts" from each point-defense gun, in the range of 10-30 depending on various factors, before impact.
Point-defense is limited by how accurately it can fire and its muzzle-velocity. A faster slug delivered accurately is best. But even firing flak, it's unlikely you'll take out more than a single missile in each "burst"- fragments lose lethality quickly with distance, and missiles can be set to "scatter" to reduce the chances of a multi-kill.
So now we have a situation where a single point-defense gun could confidently take on 10-30 missiles before intercept. It's conceivable that a battery of 10-20 would be enough to protect a ship from large salvos of incoming missiles. This will be limited, of course, by the cost in credits and mass incurred by each gun. For that matter, placement of these guns becomes an issue. Lateral gun batteries require turning the ship to bear, and this HUGELY reduces the effectiveness of armor when/ if those missiles hit you. Mounting them on the bow allows all guns to bear at once but occupies valuable real-estate AND essentially guarantees that you'll lose a great deal of your guns if a few missiles sneak through.
For that matter, missiles sporting a centimeter or two of depleted uranium in the nose will shrug off incoming projectiles, and missiles with faster closing velocities will allow less chances for point-defense fire. This of course makes missiles more costly, somewhat reducing their merit as cheap weapons.
I'm personally a fan of active point-defense. Flak missiles can intercept other flak missiles pretty easily and usually at a 1-1 ratio, and I've yet to build a dedicated anti-missile missile. For those few that sneak through, lasers and anti-capital railguns can usually take them out. I've also been building my ships with 3.5cm of maraging steel in the nose and they can shrug off direct hits from whole salvos flak missiles if taken nose-on- have yet to figure out how to armor a 100 MW laser to survive that, though.
TL;DR railguns and coilguns make alright point-defense but will be severely gimped by Real Physics (tm) when they're nerfed and can still be overwhelmed by large or fast salvos of missiles. Anti-missile missiles can be cheap (think RIM-116 for a real-life example) and plentiful and will probably be the most effective means of dealing with large salvos of missiles.