[Spaceships] Please look over my ship designs

[RogerBW]

I have a bunch of ship designs up at https://tekeli.li/wives-and-sweethearts/ on which I'd appreciate comments. I'm trying to keep the superscience mild: TL11, antimatter plasma torches are the latest shiny space drive, and FTL is via naturally-occurring gates that don't require ship systems, usually not all that far outside the system's habitable zone.

I've tested some of them against each other, but I'd appreciate thoughts on design philosophies - for example the "point defence ring" tertiary battery of rapid-firing weapons seems to be vital if you don't have shields.

(I haven't worked up costs.)

[Kale]

What sort of antimatter economy have you come up with to support shipping? I wanted to keep antimatter fairly rare in mine so even antimatter boosted drives were extremely expensive to fuel. Most ships used fusion torch or rocket drives with straight hydrogen fuel.
Antimatter lets you cram a lot of boom into a small package, so it leads to some interesting setting issues. At least fusion reactors and drives quit cold. Of course you can handwave this by assuming really good safeties on antimatter-using equipment, but you know at some point the PCs are going to try something...
P.S. Saw your blurb on antimatter, and the station locations make sense as does hijacking ships for their antimatter. This seems absurdly dangerous though if containment technology is not really reliable! Also, if the antimatter is worth more than the ship, refueling seems like a very expensive proposition.

[RogerBW]

Production at solar-powered factories. I found it necessary to have dV in the 100mps+ range in order to get useful travel times, particularly for multi-system trips (enter the system at a jump point, cross it to get to the next jump point). Fusion rockets look tempting, but the low thrust means it doesn't matter how much dV you have, you don't have time to use it.

It's a setting assumption that getting a boom rather than a prolonged fizzle out of antimatter takes work. (The energy release tends to push the reacting surfaces apart. This is the best current theory I could find while working on Meltdown and Fallout.)

[Kale]

Originally Posted by RogerBW

It's a setting assumption that getting a boom rather than a prolonged fizzle out of antimatter takes work. (The energy release tends to push the reacting surfaces apart. This is the best current theory I could find while working on Meltdown and Fallout.)

So the end effect is it is very bad for the ship it happens on, but the blast wouldn't really expand into the surroundings very far? I also suspect radiation would be pretty bad onboard any ship this happened on, but I think it would be a moot point for all but the smallest releases of antimatter.

[weby]

The iron duke seems to have broken stat list:
both the tonnage and armor are wrong.

Further it does not seem to be a battleship in idea, being almost unarmored like the destroyers. I would expect something called a battleship to devote a lot more of the mass to armor.

The Dymka seems somewhat strange in armament, with so many major batteries and no spinal battery.

Overall most of your designs seem kind of low armored and yet with low ECM, making them easy to hit and damage with comparable weapons. They seem to be designed for that anti piracy patrol, with little thought given to fighting warships.

[RogerBW]

Originally Posted by weby

The iron duke seems to have broken stat list:
both the tonnage and armor are wrong.

Further it does not seem to be a battleship in idea, being almost unarmored like the destroyers. I would expect something called a battleship to devote a lot more of the mass to armor.

The Dymka seems somewhat strange in armament, with so many major batteries and no spinal battery.

Overall most of your designs seem kind of low armored and yet with low ECM, making them easy to hit and damage with comparable weapons. They seem to be designed for that anti piracy patrol, with little thought given to fighting warships.

Thanks for this - stats should be fixed. Spinal batteries can be pretty marginal at times, though worth considering. I'll give some thought to up-armouring, but in a peer war antimatter warheads will vaporise any conceivable armour, so a heavy point defence is the only viable countermeasure. My design philosophy is more Cold War than WWII, except that carriers aren't really viable - but post-antimatter battleships are definitely less heavily armoured than the ones that were built in the old days.

(Specifically on the Dymka - replacing three 3d×10 weapons with one 4d×10 weapon is only really helpful if your target can be significantly more damaged by the 4d×10 weapon, i.e. has armour in the dDR 180-240 sort of range, and the Dymka is mostly meant to jump smaller ships. The range brackets are the same. There's probably an antiparticle variant too, though that really puts its trust in the stealth hull.)

[kreios]

A few things I've noticed:

1. Communications:

All communications are limited by lightspeed.
Jump points are 5-40 au out from the star, in the direction of the destination star (roughly one AU per lightyear);
Each in-system transmission slows things down by minutes

Since one AU is about eight light-minutes, you're going to look at 640 minutes (10h, 40m) worst-case in-system transmission time. Unless the JPs are very close, you're not going to get minute-scale transmission time. As an example, imagine two JPs, one at 0°, the other at 90° (in a 2D-approximation), both 5AU away from the star. A transmission between those two will take about an hour.

2. Missiles:
Which missiles are you using? Normal missiles have an acceleration of 5G, and the 32+cm ones have 20mps dV. This means the Iron Duke class, for example, can dodge any missile fired from rest from more than 22500km (15k miles) - a distance where the enemy is already in X-ray laser range. The super missile, on the other hand, might be too fast for the setting.

3. Survivability
There's no question here: If you are hit by an antimatter warhead, you are dead. The Juno's missile launcher does 8dx10,000, with a linked 6dx20,000. The smallest available missile launcher, with a 4dx1,000 + 3dx1,000 25kt warhead does a minimum of 7000 damage, reduced twice by armour. That's enough juuust kill (HP to 0) an SM+15 object completely made from Diamondoid armour. It's enough to completely, utterly, vapourize the Iron Duke.
You're probably aware of that (since the Iron Duke's description mentions saturation AM missile strikes), but I wanted to mention it again.
This does mean that you shouldn't mount Major Batteries of missile launchers, but rather tertiary batteries. Once each hit is a kill, you should increase your chances of a hit.

4. Example Combat
Since I want to get an idea on how the combat works: The Fearless class dastily sneak-attacks an Iron Duke. The Iron Duke is motionless until engaged; the Fearless accelerated to 0.5mps with its NTR (0.85mps left). Once the Iron Duke can no longer escape the missile (distance of 23,000km/15k miles), it fires all of its missiles. These begin acceleration once all have been fired, and will therefore arrive at once. They are thirty 40cm/10MT missiles.
Iron Duke, meanwhile, detects these missiles and begins accelerating; the goal is to keep the missiles from going much faster. The missiles are forced to expend 12 of their 20mps for course corrections, and end up with a speed of 6.5mps. Their total flight time is thirty minutes.
The Iron Duke has three different ways to engage the missiles: It can use its own missiles in an anti-missile role (each will kill one 10mile-hex of missiles; smaller missiles would again be better), it can use its Major X-Ray laser batteries (max range 20,000 miles), and it has its own point defense weaponry (max range 2,000 miles).
Aaaand I just noticed that the Iron Duke can already fire on the Fearless before the latter can ensure a missile hit. At under 20,000 miles, the Major Battery fires at -13 (range) +10 (SM) +1 (>1GJ) -1 (negated ECM) for a total of -3 (or -1 for the fixed mount). Since the Fearless requires over two hours to get into missile firing position, it will be hit often enough. Each hit does 4dx5 damage, for 20-120 (mean 70) damage. The Fearless is able to ignore 33 damage (due to armour), but the number of hits should be sufficient to destroy it.
Conclusion: If you want a meaningful missile exchange, increase their dV. To what? Let's assume that the missiles use Antimatter Plasma Torches (the new designs do; older ones might use ATRs). Let's give them an acceleration of 5G (equivalent to five APTs) and a dV of 720mps (equivalent to two fuel tanks; rest is containment, targeting and warhead). Suddenly, our missile targeting range becomes almost thirteen million kilometres (8 million miles; 43 light seconds), and our missiles will use 192mps of their dV for acceleration, arriving at close enough to 192mps at the Iron Duke.
This gives their Major Battery an engagement time of 105 seconds, or five 20-second turns. During that time, the fixed major battery can fire five shots; the two turrets a total of ten shots. These shots are at a penalty of range[-13 to -5] +1 (SM) +1 (>1GJ), for a total of -11 to -3 (-9 to -1 for the fixed mount). This kills about two missiles on average for skill-12, for 28 left.
The PD weaponry will not be able to fire except in final defense. During final defense, they will shoot at a modifier of +1 (SM) +0 (range) -0 (relative speed) up to +8 (rapid fire), for a total of +9. It mounts 120 VRF lasers, and four (and a bit) each can attack one missile. Effective probability of success for each of them is 98.1%, so the chance of a leaker is 1.3*10^7. All missiles are killed.
If we use 2 Fearless for this attack, we can expect no leakers.
If we use 4 Fearless for this attack, we can expect one or two leakers.

4. Laser Warheads
SS4 introduced the X-Ray laser warhead. A missile with that fires diameter/2 x-ray lasers with a range of 300/1,000 miles, for 10d(5) damage. These have the (in-setting) advantage of circumventing the last-ditch point defense attacks. In the example above, they'd force the point defense to fire at 1,000 miles, for a range penalty of -6 (+3 total). This decreases effective skill to 15, and chance to hit at 95.4%. Getting leakers is still pretty unlikely: 4*10^-6. (Are they allowed to dodge?)
If we use two Fearless, we're expecting 0.1 missiles leaking.
Four Fearless increase this to five leakers. These attack at +11 (SM) -6 (range) -1 (ECM), for an effective skill of 16. That's an expected 26 hits. Each does 10d(3) damage (10 to 60 damage, mean 35), against an effective DR of 45. Most won't do any damage, but we should get three or four hits. They won't be enough to disable any systems, and will only reduce HP.
Summary: Not worth it.

5. Missile summary
Think about adding two to three ECM systems onto missiles (for 5 engine, 2 fuel tanks, 3 ECM, 1 control, 1 tactical array, remainder warhead). This would increase the number of leakers during the X-Ray laser scenario (for seven against a single Fearless), and wouldn't for the AM scenario.

Now, for some more details:

Brumaire-Class Destroyer
Lacks cargo space for consumable for long space patrols.

County-class Cruiser
Is called the " County class class cruiser (RN)" on the website.
Also lacks cargo space for consumables, or for the nanofactory. Reduce the nanofactory to 1/3rd, add cargo space?
The particle beam has a maximum range of 5,000 miles and 8dx10 (3). An equivalent-sized X-ray laser would have one of 20,000 miles, and 4dx10 (5) damage. While the particle beam is better against heavily-armoured spacecraft (well, it does an effective 8dx20 against hardened armour, vs the X-ray laser's 6dx20) the range and accuracy disadvantages are, in my opinion, sufficient to reconsider.

Drake-class Survey Ship
Also lacks cargo spaces.
While it might be a good idea to have such double-role ships, in this case you're paying $300M for a secondary role. That's the cost of your reactor! I'd recommend replacing them with more fuel and cargo.

Dymka-class corvette
It has the disadvantage of everyone knowing where it is. When you're boosting, you're visible out to almost an AU even for the generic merchant ship. Once you're no longer boosting, everyone who had detected you can know exactly where you'll be (since you're ballistic). It should be usable in systems with little traffic where it can time its burns right, though.
Even so, the generic merchant will be able to detect (at +0 to skill) the Dymka at 50,000 miles distance. The X-Ray lasers only have a range of 10,000 miles, though. This means that any warship will detect the Dymka before it reaches weapon range. It might be able to inflict damage, but it surely will die.

Fearless-class destroyer
I'd recommend mentioning the NTR acc/dV in the writeup, too.
It also misses cargo space.

Iron Duke
It has two smaller/smaller super fusion power plants, but only four smaller/smaller tertiary batteries.
Since it only has 305 crew but 120 tertiary batteries, mention the effective skill level of the (probably AI-directed) PD guns.

Pirate-Modified merchant ship
It has only missile launchers; There's no advantage for it getting close. On the other hand, it has to get closer to transfer a price crew (speaking of which: No hangar!). By the way, maybe add a few more cabins: It would be nice to be able to capture several merchants before returning.

Prizrak-class corvette
This looks quite a bit nicer than the Dymka, and it should be able to hurt many spacecraft. I'd recommend dropping one of the Centre Major Batteries for two tertiary VRF PD lasers plus power generation. You can also think about dropping one of the batteries for a fifty-ton cargo hold; each can store fifty missiles.
Also, IIRC, missile launchers are never fixed or turrets.

Generic Shuttle
Especially for a military version, you can probably use reconfigurable Passenger Seat/Cargo Holds (i.e. stowable seats) for more flexible transport.
Also, do antimatter-thermal ram rockets produce radiation?
Also: If you only use it in atmosphere, drop two of the ram-rockets: You have wings, so you'll get into orbit a bit slower, but more efficiently.

Generic Ship's Boat
I'd recommend exchanging the X-Ray laser for an atmosphere-capable weapon.


Phew. That was quite a post.

Lastly: Awesome project! Looking forward to see more things.

[weby]

Originally Posted by RogerBW

Thanks for this - stats should be fixed. Spinal batteries can be pretty marginal at times, though worth considering. I'll give some thought to up-armouring, but in a peer war antimatter warheads will vaporise any conceivable armour, so a heavy point defence is the only viable countermeasure. My design philosophy is more Cold War than WWII, except that carriers aren't really viable - but post-antimatter battleships are definitely less heavily armoured than the ones that were built in the old days.

In the case of the corvette and the spinal weapon: If you switch to a spinal mount you will get a 24% probability to get through the front armor of the so called battleship, with the current weapons you have 1.85%.

Of course with the current armament you can just destroy it very quickly if you get a shot at anything except the front, but that is not likely given the low acceleration. But on average 32 hits on the side/rear armor has the "battleship" at below -HP so having 8 weapons is much better for such a scenario.

Brumaire class destroyer has 24% probability of shooting through the front armor of the "battleship" and the side armor is basically 60% damage reduction with every hit expected to get though so there is no need to use a missile to kill a battlehip. Of course the side armor does protect fairly well from hits beyond 1/2d.

Adding one more armor system to each location would make frontal beam attacks basically futile and sides to be well defended with most hits being stopped.

Given the high number of point defense weapons that ships have I would expect that the missiles are mostly for trying to get the lucky but extremely unlikely hit, but real combat damage would come from the very likely beam hits.

[RogerBW]

Kreios:

Looks as if you're considering Advanced Combat with full vector manoeuvres for all participants, whereas I'm mostly interested in Basic Combat. (While it's not part of this thread, the campaign brief is that I'm more interested in why the fight has been happening than in exactly what happens during it.)

Agreed, closing down to multiple smaller missile launchers makes sense in some cases. On the other hand, they do want a weapon with long reach but that can cripple, rather than destroy, an opponent - at least some of the missiles on board will be conventional warheads, unless there's a full-on war going on.

Remember that the Fearless is a generation behind most of the other craft here.

I'll take other comments on board and post updates...

[RogerBW]

(Many updates.)

Having a full-size nanofactory gives +1 HT - that's why the County did. But armour is probably more useful, in the end.

Dymka: as I see it, the power plants are rigged for a quick startup when it's detected and has to close to engage.

I've added cargo hold space, though I assume that hangar bays are generally not full and will have extra stores stowed in them at the start of a cruise.

I see nothing in the rules to suggest that missile launchers aren't fixed/turret/spinal just like beam launchers.

Suggesting that the Prizrak should give up some of its firepower in favour of survivability is to misread the priorities of the Novaya Europan naval architects.

The shuttle is a generic one: it can land vertically in vacuum if it needs to. Worlds with their own aerospace manufacturing capabilities, or simply enough money to buy custom-made craft, will certainly have ones that are tailored to their particular environments.

(Yes, there's some radiation, but it's mostly gammas; it doesn't leave you with neutron-enriched air like the fission air-ram.)