Dreadnought or Mothership (RAR!)

[Eternal_Freedom]

The truss structure works best for ships designed with modern-day technology where every kilogram does count. The fact that this turbosuperdreadnought is 12 km long and is still able to accelerate to useful sublight speeds means they clearly have absurdly powerful sublight engines, to the point where trying to save every last kilogram is no longer necessary.

[Sky Captain]

Acceleration rate would still count. If my ship while having similar weapons, engines and shielding for example have 10 % less mass it would accelerate faster giving more tactical options. For example if enemy ships decide to run I could pursue and destroy them or if I had to break off from engagement I could use my superior acceleration capability to open up range and escape effective enemy weapon range.

[Eternal_Freedom]

Except in this scenario you are not fighting ships of equal size or power, so they will probably always be able to out-accelerate you. And as Simon has said, there are plenty of reasons for having a hull, even if it is only lightly armoured.

[Simon_Jester]

It's possible, but there are reasons to do otherwise. Among other things, the risk of the ship being shot at in some way while unshielded, or by some category of threat which bypasses the shields. It may be impossible to armor the ship against gigaton-range weapons. But when dealing with multi-kilometer ship you could trivially make it 'armored' against anything short of a sizeable nuclear weapon, without really doing anything recognizable as 'armor' as opposed to 'hull.' Just like very large seagoing ships have to be made out of multiple-inch-thick steel just for structural reasons regardless of any attempt to armor them.

And the mass penalty of doing so is trivial compared to the volume of the ship, assuming you are using that volume efficiently and it's not just big empty spaces criss-crossed with trusses and framework.

There are good reasons NOT to have big empty spaces inside your 'ship' of connected modules in combat, because doing so increases your target profile. Having several hundred meters of truss between your engines and reactor isn't a problem for designing a civilian spaceship to explore Jupiter. It's a problem if you're being shot at, though, because then you're adding a new failure mode to the ship (truss getting shot because it's a big target) which would otherwise not be a factor.

[Eternal_Freedom]

I can't recall if missiles were a dominant weapon in this setting, but if they are then having a full hull for your dreadnought gives you much more room for point-defence mounts, meaning that if your shields drop entirely or partially you may be able to survive a short while by shooting down the missiles before hitting you.

[LastShadow]

Realistically the Mothership is the better option, an essentially mobile Fortress, shipyard and assorted production facility.

The dreadnought however would be the more fun option. You get essentially a trump card, something that can drop in system and devastate the enemy.

The vicious person who needs to win in me, says dreadnought. BUT the pragmatist says Mothership, and in this case, the pragmatist will win in my decision. Based solely on purely hypothetical reasoning, i mean its literally worst case scenario.

I would say the mothership, has in the long run more sustainability for a fleet, a dreadnought is a mean mean prospect to go up against, but say, for arguments sake, that the ability to make FTL jumps gets removed due to technobabble, cumulative effect of Hyperdrives destabilize the current on which they travel. In that case your Dreadnought is utterly useless, where your Mothership is now king of the pond, having the ability to replenish forces on the front line while traveling, and resupplying at the same time. Clearly thats a worst case scenario. But its an option id rather have, than not have.

Now the big question for me is what does it take, to eliminate the various ships. For example, can a Mothership produce enough vessels that in combination with itself could either fight a Dreadnought to a stand still, or beat it? How large of a fleet would you need to take out a dreadnought?

In the end i sitll pick a mother ship, but im just curious.

[Eternal_Freedom]

I would agree with you that the Mothership is a more pragmatic option if this were a generic "which would you build going forwards?" type of thread. For me, the clincher is that you know the enemy is going to attack you shortly after either super-ship is completed. The Mothership will be useful in a war of attrition, but frankly that's something you want to avoid. The Dreadnought allows you to inflict a devastating loss to the enemy at little cost to yourself, tipping the scales in favour of yourself and your allies.

On further consideration I've realised there is perhaps a better option. Have your shipyard begin building a Dreadnought but launch an immediate pre-emptive strike at your opponents shipyards. If both sides are roughly even;y matched then you can prevent them from building reinforcements while still building new ships yourself and you have the super-ship on the way eventually too.

Some technobabble means of blocking the super-ships FTL would be crippling to either one. Sure the Mothership can continue to build ships, but if this is a localised effect their FTL won't work either, so the ship is as good as lost.

[LastShadow]

I would agree with you that the Mothership is a more pragmatic option if this were a generic "which would you build going forwards?" type of thread. For me, the clincher is that you know the enemy is going to attack you shortly after either super-ship is completed. The Mothership will be useful in a war of attrition, but frankly that's something you want to avoid. The Dreadnought allows you to inflict a devastating loss to the enemy at little cost to yourself, tipping the scales in favour of yourself and your allies.

On further consideration I've realised there is perhaps a better option. Have your shipyard begin building a Dreadnought but launch an immediate pre-emptive strike at your opponents shipyards. If both sides are roughly even;y matched then you can prevent them from building reinforcements while still building new ships yourself and you have the super-ship on the way eventually too.

Some technobabble means of blocking the super-ships FTL would be crippling to either one. Sure the Mothership can continue to build ships, but if this is a localised effect their FTL won't work either, so the ship is as good as lost.

Valid points all, but the point i was making with the technobabble, is the Mothership can make vessels in transit, So say its a year out via sublight to where you are going, it would make sense to have those ships there in the year it takes to build the ships, as opposed to a year to build and a year to deploy.

In the case of a preemptive strike, in a space war, where presumably you know all sides are building ships of that size, wouldnt you either prepare for the strike, or launch one of your own?

But in the end, it depends on what a standard, fleet or armada is in this universe, and what it would take fleet wise to take out a Dreadnought. Large fleet, two large fleets, three? Could the ships buildable by a Mothership constitute enough of a fleet combined with the mothership to go toe to toe?

Also a Mothership could work as a mobile base with which to rebuild after a devastating attack. I guess it all depends on what your goals are, total devastation or survival. Oh and generally every war is a war of attrition, he who builds and trains slower will lose.

[Esquire]

Think of the Mothership as the 'Soviet strategy.'* Sure, it can't stand up to the Dreadnought - but the fleet it supports, with the swarms of missiles and attack drones it produces, absolutely can. And since it's a full industrial complex on its own, the multi-month travel time between systems means that you can run up a nigh-infinite supply of anti-Dreadnought missiles given the slightest opportunity, or else replenish losses up to either the maximum number of skeleton crews you can muster or, assuming semicompetent AI, up to the total mineral resources of wherever you happen to be.

*Metaphorically and popularly. I am 1000% not interested in debating WWII here.

[Eternal_Freedom]

Valid points all, but the point i was making with the technobabble, is the Mothership can make vessels in transit, So say its a year out via sublight to where you are going, it would make sense to have those ships there in the year it takes to build the ships, as opposed to a year to build and a year to deploy.

In the case of a preemptive strike, in a space war, where presumably you know all sides are building ships of that size, wouldnt you either prepare for the strike, or launch one of your own?

But in the end, it depends on what a standard, fleet or armada is in this universe, and what it would take fleet wise to take out a Dreadnought. Large fleet, two large fleets, three? Could the ships buildable by a Mothership constitute enough of a fleet combined with the mothership to go toe to toe?

Also a Mothership could work as a mobile base with which to rebuild after a devastating attack. I guess it all depends on what your goals are, total devastation or survival. Oh and generally every war is a war of attrition, he who builds and trains slower will lose.

Actually, unless the stars are unusually close and the Mothership (and any ships it builds, it can't keep everything docked inside while still building stuff) can accelerate to near-lightspeed, it will be multiple years before you arrive at a destination even a close distance away, by which time you may well have lost the war.

As for the second paragraph, per the OP we're the only ones building such ships (as we have the FTL breakthrough to make them faster), though you could reasonably extend that to our allies (as I suggested earlier, this would be an optimum solution; your side is able to build two Dreadnoughts and one Mothership to support them). As for launching a pre-emptive strike, that's exactly what I suggested.

For the third paragraph, the OP states the Dreadnought can challenge entire fleets and win. I would interpret that to mean that it can't, by itself, engage the entire Navy of one of the hostile nations and win, but it can engage and defeat large portions of the entire Navy, and it is unreasonable to expect the enemy to be able to concentrate that much force against one ship without leaving themselves terribly exposed.

In fact, that may be an even better use for the Dreadnought: a distraction. It is powerful enough that the enemy cannot ignore it's presence in their space but has to devote a large portion of their military to defeating it, thus leaving them fewer ships to defend the rest of their space while the Dreadnought can defeat many smaller groups. With it's superior FTL speed, it could move from industrialised system to industrialised system, destroying infrastructure and defences before moving on before reinforcements can arrive.

As for your final paragraph, if building the Mothership as a contingency consumes so many resources that my nation (which is on a roughly even basis with the other powers per the OP) that I am open to such a devastating attack then it's a damned stupid decision to build one. Especially since the Mothership could not possibly out-build three enemy nations when it can only build destroyers or smaller and only five of those in three months, plus twelve frigates in six weeks and twenty corvettes in three weeks. Yes, the Mothership can sustain a fleet but not an entire nation.

My goal in this war is to win, not merely survive. Given the conditions in the OP this Dreadnought/Mothership choice is not a last-ditch do-or-die action (like it is in, say, Homeworld which quite clearly inspires this thread) but a choice of the best way to exploit the new FTL tech. I could choose (as others have said) to build neither and pour the resources into battleships and carriers.

This is a war of conquest and subjugation, not annihilation. As for it being a war of attrition, this is why I suggested an immediate attack against enemy shipyards and other infrastructure as an alternative choice.

[Eternal_Freedom]

Think of the Mothership as the 'Soviet strategy.'* Sure, it can't stand up to the Dreadnought - but the fleet it supports, with the swarms of missiles and attack drones it produces, absolutely can. And since it's a full industrial complex on its own, the multi-month travel time between systems means that you can run up a nigh-infinite supply of anti-Dreadnought missiles given the slightest opportunity, or else replenish losses up to either the maximum number of skeleton crews you can muster or, assuming semicompetent AI, up to the total mineral resources of wherever you happen to be.

*Metaphorically and popularly. I am 1000% not interested in debating WWII here.

Sorry for the double-post, but I wanted to address this separately.

Whether or not the Mothership and the fleet it builds can square off against the Dreadnought is irrelevant. We are the only nation building such a vessel. If we chose one design the other will remain a paper design at most.

You bring up a solid point about crews though. The OP says destroyers have a crew of at least 250, Frigates at least 80 and corvettes at least 40. So given that the ship can build (in 3 months) 5 destroyers, 24 frigates and 80 corvettes, you need 6,370 extra crew. I really don't see how you can sustain that for long. To quote the OP: "Long story short, having a Mothership along with a fleet on a military expedition would simplify logistics massively." The Mothership is meant as an uber-support ship, not something that can produce enough on it's own to win the war.

The Mothership may be able to contribute to a decisive battle a year into the war. The Dreadnought can bring about a decisive victory immediately. That alone makes it more attractive.

[Simon_Jester]

I would say the mothership, has in the long run more sustainability for a fleet, a dreadnought is a mean mean prospect to go up against, but say, for arguments sake, that the ability to make FTL jumps gets removed due to technobabble, cumulative effect of Hyperdrives destabilize the current on which they travel. In that case your Dreadnought is utterly useless, where your Mothership is now king of the pond, having the ability to replenish forces on the front line while traveling, and resupplying at the same time. Clearly thats a worst case scenario. But its an option id rather have, than not have...

That's not a worst case scenario, that's a horror movie. I mean, it'd be like designing warships in real life for the "what if evil sorcerors make steam engines and electricity magically stop working" scenario.

I favor the mothership myself, but only because in this setting round trip times from the center of an empire to the zone of combat operations are likely to be measured in months. So having logistical support for a fleet which is physically present in the war zone, and which cannot easily be 'cut off' by an enemy attack (because the mothership is so big and tough compared to normal ships) is a major asset. It's not about what happens of technology magically changes, it's just that under perfectly normal conditions logistics is important and being able to resupply and repair your ships matters.

I would agree with you that the Mothership is a more pragmatic option if this were a generic "which would you build going forwards?" type of thread. For me, the clincher is that you know the enemy is going to attack you shortly after either super-ship is completed. The Mothership will be useful in a war of attrition, but frankly that's something you want to avoid. The Dreadnought allows you to inflict a devastating loss to the enemy at little cost to yourself, tipping the scales in favour of yourself and your allies.

The problem is one of mobility and scale. The dreadnought can destroy any one thing, but even with its upgraded FTL speed it can't destroy many things in less time than it takes your enemy to overrun you by normal means. There is also the awkward question of how well you can resupply the dreadnought while it is engaged in 'deep strike' missions in the heart of enemy territory. How long does it take such a ship to run out of fuel?

On further consideration I've realised there is perhaps a better option. Have your shipyard begin building a Dreadnought but launch an immediate pre-emptive strike at your opponents shipyards. If both sides are roughly even;y matched then you can prevent them from building reinforcements while still building new ships yourself and you have the super-ship on the way eventually too.

In that case you are fated to five years of conventional warfare before the dreadnought is finished. If that's a good idea, then it implies you were perfectly capable of winning without the dreadnought (in which case it is largely useless). If it's NOT a good idea, then you've just committed yourself to five grueling years of total warfare with all the associated casualties.

Whereas I thought you were trying to avoid a war of attrition...

[LastShadow]

I would say the mothership, has in the long run more sustainability for a fleet, a dreadnought is a mean mean prospect to go up against, but say, for arguments sake, that the ability to make FTL jumps gets removed due to technobabble, cumulative effect of Hyperdrives destabilize the current on which they travel. In that case your Dreadnought is utterly useless, where your Mothership is now king of the pond, having the ability to replenish forces on the front line while traveling, and resupplying at the same time. Clearly thats a worst case scenario. But its an option id rather have, than not have...

That's not a worst case scenario, that's a horror movie. I mean, it'd be like designing warships in real life for the "what if evil sorcerors make steam engines and electricity magically stop working" scenario.

I favor the mothership myself, but only because in this setting round trip times from the center of an empire to the zone of combat operations are likely to be measured in months. So having logistical support for a fleet which is physically present in the war zone, and which cannot easily be 'cut off' by an enemy attack (because the mothership is so big and tough compared to normal ships) is a major asset. It's not about what happens of technology magically changes, it's just that under perfectly normal conditions logistics is important and being able to resupply and repair your ships matters.

I would agree with you that the Mothership is a more pragmatic option if this were a generic "which would you build going forwards?" type of thread. For me, the clincher is that you know the enemy is going to attack you shortly after either super-ship is completed. The Mothership will be useful in a war of attrition, but frankly that's something you want to avoid. The Dreadnought allows you to inflict a devastating loss to the enemy at little cost to yourself, tipping the scales in favour of yourself and your allies.

The problem is one of mobility and scale. The dreadnought can destroy any one thing, but even with its upgraded FTL speed it can't destroy many things in less time than it takes your enemy to overrun you by normal means. There is also the awkward question of how well you can resupply the dreadnought while it is engaged in 'deep strike' missions in the heart of enemy territory. How long does it take such a ship to run out of fuel?

On further consideration I've realised there is perhaps a better option. Have your shipyard begin building a Dreadnought but launch an immediate pre-emptive strike at your opponents shipyards. If both sides are roughly even;y matched then you can prevent them from building reinforcements while still building new ships yourself and you have the super-ship on the way eventually too.

In that case you are fated to five years of conventional warfare before the dreadnought is finished. If that's a good idea, then it implies you were perfectly capable of winning without the dreadnought (in which case it is largely useless). If it's NOT a good idea, then you've just committed yourself to five grueling years of total warfare with all the associated casualties.

Whereas I thought you were trying to avoid a war of attrition...

You bring up a great counter point to my argument, but in part largely the one i was trying to make, a logistical support ship, with onboard shipyards is incredibly useful.

[Simon_Jester]

It certainly is- it's just a good idea, when making a strategic decision, to separate plausible threats from fantasy ones.

I've seen quite a few people propose stupid things as a "perfectly reasonable" reaction... to a problem that was realistically never going to happen in the first place.

[Eternal_Freedom]

On further consideration I've realised there is perhaps a better option. Have your shipyard begin building a Dreadnought but launch an immediate pre-emptive strike at your opponents shipyards. If both sides are roughly even;y matched then you can prevent them from building reinforcements while still building new ships yourself and you have the super-ship on the way eventually too.

In that case you are fated to five years of conventional warfare before the dreadnought is finished. If that's a good idea, then it implies you were perfectly capable of winning without the dreadnought (in which case it is largely useless). If it's NOT a good idea, then you've just committed yourself to five grueling years of total warfare with all the associated casualties.

Whereas I thought you were trying to avoid a war of attrition...

The aim would be to so cripple the enemy infrastructure that they cannot sustain a war for very long whereas I can. I launch the raid then stand on the defensive, with the advantage of fixed defenses, nearby repair yards and so forth. They can attack with their extant forces but they can't realistically win with those and only those when my infrastructure is intact. Thus they will either launch an attack and probably be defeated and be so weakened they cannot continue, or they recognise they must rebuild their shipyards etc. before attacking again, in which case I most likely have my Dreadnought or Mothership completed.

It's not so much "winning" outright with my existing forces, but delaying and weakening the enemy so that, in five years when my Dreadnought is ready they maybe are back up to where they were at the start, rather than having 5 years of extra production of warships available.

[Simon_Jester]

It's not like they'll just stop fighting you if you manage to damage their infrastructure in raids. They may not be very aggressive but they'll keep trying to find some way to screw you.

Also, bear in mind that with such slow mobility, your attacks against their infrastructure might just plain fail. If you are confident of your ability to do that, then as noted, you have the ability to decide the war in your favor quickly.

So why is your dreadnought even necessary?

There's also the risk that, with most of your military being occupied for many months by these deep raiding operations into enemy space, the enemy's frontline fleet commanders will opportunistically launch attacks into your frontier while most of your forces are in transit. You may be opening yourself to defeat in detail.

[gigabytelord]

The aim would be to so cripple the enemy infrastructure that they cannot sustain a war for very long whereas I can. I launch the raid then stand on the defensive, with the advantage of fixed defenses, nearby repair yards and so forth. They can attack with their extant forces but they can't realistically win with those and only those when my infrastructure is intact. Thus they will either launch an attack and probably be defeated and be so weakened they cannot continue, or they recognise they must rebuild their shipyards etc. before attacking again, in which case I most likely have my Dreadnought or Mothership completed.

It's not so much "winning" outright with my existing forces, but delaying and weakening the enemy so that, in five years when my Dreadnought is ready they maybe are back up to where they were at the start, rather than having 5 years of extra production of warships available.

And what if by some fluke they either see you coming or infiltrate your intelligence chain and setup an ambush? One example of this I can remember right off the top of my head are the opening attacks on the Manticoran Alliance systems by the Republic of Haven. The attacks all failed utterly and were either destroyed or driven off after inflicting little damage. Granted the situation was very different but you could find yourself in an alarmingly similar spot. Hence the reason why I would go with the options I listed before hand. Always act as if they know exactly what you're going to do even if they obviously don't. And there's still no reason they won't choose to start building equal size ships (if slower in FTL) and adjust their fleet actions accordingly.

Also if you can drag out the conflict long enough eventually they'll start having man power problems if you keep mouse trapping their fleets and do your damnedest to inflict high tonnage casualties. In such a setting I figure ships will be easy to replace but good officers and crew not so much. However I do agree that finding a way to either destroy or force them to redirect their industrial capacity is a good idea but only if it's technically and militarily possible.

[Eternal_Freedom]

It's not like they'll just stop fighting you if you manage to damage their infrastructure in raids. They may not be very aggressive but they'll keep trying to find some way to screw you.

Also, bear in mind that with such slow mobility, your attacks against their infrastructure might just plain fail. If you are confident of your ability to do that, then as noted, you have the ability to decide the war in your favor quickly.

So why is your dreadnought even necessary?

There's also the risk that, with most of your military being occupied for many months by these deep raiding operations into enemy space, the enemy's frontline fleet commanders will opportunistically launch attacks into your frontier while most of your forces are in transit. You may be opening yourself to defeat in detail.

Come to think of it, nothing in the OP says a supership is necessary and we have to build one.

I will concede the rest of the point though, this FTL is a lot slower than ones I am used to contemplating where such deep raids are feasible.

That being said I think the best option is to share this technology and designs with my allies, and collectively build 3 superships (2 Dreadnoughts and 1 Mothership) that I can send off as a unit to go wreak havoc on the enemy indefinitely.

[Simon_Jester]

Alternatively, you could arrange a mutual-defense pact in which one or two of the nations agrees to turn out massive numbers of conventional ships while one or two alliance-wide flagships are constructed by you (or someone else).

[Eternal_Freedom]

That's also a good idea. I think most people have been overlooking the fact that in this scenario we have allies and so do our enemies, so its not as simple as "dreadnought or mothership?"

[Sky Captain]

It's possible, but there are reasons to do otherwise. Among other things, the risk of the ship being shot at in some way while unshielded, or by some category of threat which bypasses the shields. It may be impossible to armor the ship against gigaton-range weapons. But when dealing with multi-kilometer ship you could trivially make it 'armored' against anything short of a sizeable nuclear weapon, without really doing anything recognizable as 'armor' as opposed to 'hull.' Just like very large seagoing ships have to be made out of multiple-inch-thick steel just for structural reasons regardless of any attempt to armor them.

Maybe I'm thinking too much in terms of Kerbal Space Program where spacecraft usually are small scale and every kilogram counts. This scenario is closer to something like O Neil colony crammed full of weapons, engines, shield generators and massive structure to hold everything together while under high acceleration.

There are good reasons NOT to have big empty spaces inside your 'ship' of connected modules in combat, because doing so increases your target profile. Having several hundred meters of truss between your engines and reactor isn't a problem for designing a civilian spaceship to explore Jupiter. It's a problem if you're being shot at, though, because then you're adding a new failure mode to the ship (truss getting shot because it's a big target) which would otherwise not be a factor.

That's good point, combat ship would want minimum possible target profile so there would as little empty spaces inside as possible.

Except in this scenario you are not fighting ships of equal size or power, so they will probably always be able to out-accelerate you. And as Simon has said, there are plenty of reasons for having a hull, even if it is only lightly armoured.

That actually may be a problem because Dreadnought could find it difficult to force engagement if enemy decides to break off and run for hyperlimit. If normal combat doctrine for enemy fleets when faced with overwhelming force is to run to avoid certain destruction then Dreadnought would be less useful as shipkiller although still highly useful to attack enemy infrastructure protected by static defenses

That being said I think the best option is to share this technology and designs with my allies, and collectively build 3 superships (2 Dreadnoughts and 1 Mothership) that I can send off as a unit to go wreak havoc on the enemy indefinitely.

That is good idea especially since it would allow full use of higher FTL speed. If Mothership or Dreadnought were traveling together with smaller ships they would have to slow down to match slower FTL speed of conventional ships essentially negating their better strategic mobility and probably the main reason why to build such giants at all.