SDB's vs. Warships

[phavoc]

Most of the material out there talks about how an attacker needs to be very concerned about surviving SDB's when invading a system. But nowhere have I found a real reason why.

The Dragon class SDB is only 400 tons. It's just a target to a 5,000 ton destroyer. The rules talk about being 'vulnerable' during gas giant refueling, but nowhere have I found rules outlining the mechanics.

The only thing I can think that might need to worry about it would be unarmed cargo ships, tankers or troop transports. But most every ship has at least some armament, and you wouldn't leave your fleet train unguarded. So that doesn't really fit either.

All I can think of is that the SDB concept meant a lot more when the upper limit on hulls was just 2,000 tons. THEN having a ship 1/4 your size that was optimized to be nothing but an in-system ship-killer made it a true threat. But once destroyers started coming out at 5k tons, SDB's are an annoyance, and only a threat in truly large numbers - which kind of goes against their whole idea of hiding individually, in pairs or small groups waiting to attack from stealth.

Does anybody else get the idea that the threat from SDB's is overrated?

 

[Galadrion]

Not really. Remember, monitors are SDBs, as well. SDBs are not limited in size, any more than any other type of warship.

The advantages to the smaller classes, such as the Dragon, is that they can be cranked out in large numbers rather quickly, and that large numbers of smaller hulls allow more strategic flexibility. If you have forty quarter-gigacredit SDBs, you can distribute them against a wider range of threats, and against more targets simultaneously than if you only have four ships at two-and-a-half gigacredits apiece.

If you want to test out how viable the concept is, try putting together a test scenario, TCS-style - say, a one-billion or ten-billion credit squadron on each side, and see how they fare against each other, probably in a best-out-of-three or -five setting. I would say that both sides should either use published designs or be allowed to use customs designs - it's not a fair test to limit one side to designs which go all the way back to the Core Rulebook while the other side is allowed to be custom-designed using the latest and greatest available equipment. Level playing field, here.

Personally, I think the advantage lies with the larger ships, but it's not entirely cut and dried. It's certainly still an interesting set of tactical and strategic questions - much more complicated and intricate than it appears on the surface.

 

[F33D]

All I can think of is that the SDB concept meant a lot more when the upper limit on hulls was just 2,000 tons. THEN having a ship 1/4 your size that was optimized to be nothing but an in-system ship-killer made it a true threat. But once destroyers started coming out at 5k tons, SDB's are an annoyance, and only a threat in truly large numbers - which kind of goes against their whole idea of hiding individually, in pairs or small groups waiting to attack from stealth.

Does anybody else get the idea that the threat from SDB's is overrated?

I think you are right about the large ship tonnage limit being the root of this. IMTU there are powerful nuc torps. If one goes off close to a ship (within 1-2 km) while in atmosphere, say goodbye to the ship...

 

[phavoc]

Not really. Remember, monitors are SDBs, as well. SDBs are not limited in size, any more than any other type of warship.

The most oft-cited SDB size is the Dragon, though canon material mentions SDB's in the 1,000 ton range.

The advantages to the smaller classes, such as the Dragon, is that they can be cranked out in large numbers rather quickly, and that large numbers of smaller hulls allow more strategic flexibility. If you have forty quarter-gigacredit SDBs, you can distribute them against a wider range of threats, and against more targets simultaneously than if you only have four ships at two-and-a-half gigacredits apiece.

Yes, that's true. Plus they can be built lots of places and transported where needed. There's even a Dragon-class SDB transport ship designed to shuttle them between systems.

If you want to test out how viable the concept is, try putting together a test scenario, TCS-style - say, a one-billion or ten-billion credit squadron on each side, and see how they fare against each other, probably in a best-out-of-three or -five setting. I would say that both sides should either use published designs or be allowed to use customs designs - it's not a fair test to limit one side to designs which go all the way back to the Core Rulebook while the other side is allowed to be custom-designed using the latest and greatest available equipment. Level playing field, here.

Nothing I've read anywhere leads me to believe any system has that kind of SDB defense, at least not where you'd have equivalent tonnage. Even a hundred Dragon SDB's are only equivalent to a single 40k class cruiser tonnage wise, though it's probably more fair to say a 60-65k class cruiser is their equivalent. Using your spinal mount on them would be kind of a waste of time, but those SDB's are going to die by the handful every combat round. The only mount standard missile or lasers, and if you have a heavily armored ship, the rules basically say you can laugh off those kinds of weapons.

Personally, I think the advantage lies with the larger ships, but it's not entirely cut and dried. It's certainly still an interesting set of tactical and strategic questions - much more complicated and intricate than it appears on the surface.

Agreed. Against merchantmen or very lightly armed transports they are a threat. They are only a threat against real warships if you have a whole lot of them. But this, too, is part of the Traveller universe, where lots of armor, meson screens and nuclear dampers make it almost impossible for small, lighter-armed ships to be more than a nuisance.

 

[Condottiere]

Those rockets burn hydrogen which means you have to be very careful on turning on the afterburner. That makes lying doggo in the gas giants ideal, since they can tank up at any time, rather risky unless those dipping their wick have their rears covered or so protected it's a kamikaze mission.

As regards to size, they probably are there to pick off the unwary and weak, attritioning any task force, forcing them to divert excessive escorts for convoy duty.

The real point is to deny an attacking force the opportunity for an easy refueling, since if we assume the primary world has water, once it's secure, they can deal with the SDBs at their leisure.

 

[simonh]

Dragons are your coastal patrol boat/motor torpedo boat equivalent. They are the sort of ship you can litter around your system to pick on small time pirates, smugglers, enemy scout ships and such or hide for surprise attacks against support ships and transports. Therefore they are the kind of ship your players are likely to come across.

You will also have the heavies, your nuclear attack sub or battleship equivalents out there, but they will spend all their time lurking inside gas giants trying not to be seen by anyone, include player characters.

Simon Hibbs

 

[Nerhesi]

Those are just the SDBs you see as example in books too. Ultimately, an SDB has 20 to 40% more space than a ship of similar size to use on weapons due to the lack of jump fuel requirements.

 

[phavoc]

Those rockets burn hydrogen which means you have to be very careful on turning on the afterburner. That makes lying doggo in the gas giants ideal, since they can tank up at any time, rather risky unless those dipping their wick have their rears covered or so protected it's a kamikaze mission.

As regards to size, they probably are there to pick off the unwary and weak, attritioning any task force, forcing them to divert excessive escorts for convoy duty.

The real point is to deny an attacking force the opportunity for an easy refueling, since if we assume the primary world has water, once it's secure, they can deal with the SDBs at their leisure.

Agreed. But you can just as easily send along a 5k destroyer to perform it's escort duties in the gas giant and any unlucky 400ton SDB is going on a suicide run to hit the tanker (which also might have it's own defenses).

Dragons are your coastal patrol boat/motor torpedo boat equivalent. They are the sort of ship you can litter around your system to pick on small time pirates, smugglers, enemy scout ships and such or hide for surprise attacks against support ships and transports. Therefore they are the kind of ship your players are likely to come across.

You will also have the heavies, your nuclear attack sub or battleship equivalents out there, but they will spend all their time lurking inside gas giants trying not to be seen by anyone, include player characters.

Simon Hibbs

A 1k ton SDB is certainly a threat to any support ship or transport. And the books have said that SDB's also perform patrols, piracy suppression, etc and whatnot during peacetime. But they also say the Dragon is the most common SDB, which leads me to believe the 1k tonners are few and far between.

Those are just the SDBs you see as example in books too. Ultimately, an SDB has 20 to 40% more space than a ship of similar size to use on weapons due to the lack of jump fuel requirements.

Yes, like a battlerider they have more bang for the buck for their size. The biggest difference is they have more tonnage to set aside for armor, because at 400 tons they can't mount any bigger weaponry.

 

[Condottiere]

Unless they bring their own tankers with them, any attacking force is likely about to run dry. Any juice the tankers have left will be for tactical maneuvering, which is where the lighter units come in because they consume less gas, they can do more scouting,

 

[dragoner]

Mmmm, big old planetoid monitor sitting in a GG's ring, nasty. The old Guardian - which is the 400ton SDB, was a sort of all purpose military craft, good gunship in atmosphere as well. The mong Dragon is a 1200ton J4 stealth raider: "...designed to carry heavy firepower behind enemy lines and disrupt lines of supply as much as possible." S10, pg 31.

 

[Rockymountainnavy]

If you use Fifth Frontier War as a guide SDBs are best used as a stay behind guerrilla type force to complicate the use of a system. Interestingly, in FFW the presence of SDBs does not hinder refueling at a gas giant but only refueling from oceans. They are also useful in interface combat and can make the battle for control of a world become more drawn out.

I personally see SDBs as a type of law enforcement unit in peacetime and a militia in war. In a small ship universe (ACS) they may be able to fight but in the large ship (BCS) they are better used as a nuisance or guerrilla unit.

 

[phavoc]

Unless they bring their own tankers with them, any attacking force is likely about to run dry. Any juice the tankers have left will be for tactical maneuvering, which is where the lighter units come in because they consume less gas, they can do more scouting,

SDB's could harass fuel ships, or refueling shuttles. But most major combatants and escorts seem to be able to refuel on their own, so pairing those ships up would make the SDB's vulnerable to ships that outfight and outgun them. Back to being minor harrassment.

Mmmm, big old planetoid monitor sitting in a GG's ring, nasty. The old Guardian - which is the 400ton SDB, was a sort of all purpose military craft, good gunship in atmosphere as well. The mong Dragon is a 1200ton J4 stealth raider: "...designed to carry heavy firepower behind enemy lines and disrupt lines of supply as much as possible." S10, pg 31.

Easily avoided, but not something you could leave behind. GG's are BIG, and you could also keep the planet between you. They'd (asteroid forts) be better deployed around the main system world(s) than a GG.

Yeah, I caught the Dragon 1,200 ton ship, and the old Dragon SDB with the same name.

If you use Fifth Frontier War as a guide SDBs are best used as a stay behind guerrilla type force to complicate the use of a system. Interestingly, in FFW the presence of SDBs does not hinder refueling at a gas giant but only refueling from oceans. They are also useful in interface combat and can make the battle for control of a world become more drawn out.

I personally see SDBs as a type of law enforcement unit in peacetime and a militia in war. In a small ship universe (ACS) they may be able to fight but in the large ship (BCS) they are better used as a nuisance or guerrilla unit.

SDB's would definitely work if they were up against civilian freighters. In packs they could easily take out non-escorted ships and freighters. But they are just toast against real naval vessels. Their naming nomenclature doesn't really fit.

 

[locarno24]

Easily avoided, but not something you could leave behind. GG's are BIG, and you could also keep the planet between you. They'd (asteroid forts) be better deployed around the main system world(s) than a GG.

Agreed. A Gas Giant's gravity well is huge (one of the reasons it's so scary a place to refuel because you risk being hours inside the gravity well if you get jumped by attackers)

All I can think of is that the SDB concept meant a lot more when the upper limit on hulls was just 2,000 tons. THEN having a ship 1/4 your size that was optimized to be nothing but an in-system ship-killer made it a true threat. But once destroyers started coming out at 5k tons, SDB's are an annoyance

Which is fair enough. The same argument can be made for the 'warships' in the core rulebook - a mercenary cruiser purely armed with beam lasers is a joke after the beam laser was massively downgraded.

But yes, System Defence Boats are ultimately heavy customs/antipiracy boats. They will not and cannot stop a 20,000 dTon ship of the line, especially since many designs I've seen pack missile tubes or only light bay weapons.

That said, they can be a reasonable threat, because a 400 dTon ship can be built around a large bay calibre energy weapon that you couldn't fit on a 400 dTon jump-capable ship.

A single large bay isn't a threat to a capital ship, but let's assume that a lone raider is likely to be cruiser sized - battleships generally tool around in groups, and no system navy can realistically be expected to fend off a major powers Battle Squadrons. That lone cruiser or heavy cruiser is probably in the 50-70 KdTon range. It's not unreasonable to imagine an entire SDB squadron engaging this thing if you're defending a major world, and whilst they will suffer casualties, they can probably take it.

To put things in perspective, we're told that most 'proper' navy warships are Jump-4 capable - see the reference in Sector Fleet to "Fleet Manouvrability". This means that a 50,000 dTon ship wastes 20,000 dTons on fuel capacity and a further 2,500 dTons on its jump drive.

Therefore, its actual 'combat systems' volume is about 27,500 dTons - or the same as 55 500 dTon SDBs, it's just hauling 22,500 dTons and 7 BCr worth of dead hull around in a fight.

Its equivalent of 55 SDBs with a large, high yield particle beam bay each, puts out a barrage of 495-Particle-Long-9. Allowing for a fair mix of evasion, armour, sensor locks, etc, you can get a barrage with a DM-2 or not far shy, which gives you an average of...pretty much 100% damage.

500 barrage damage is enough to blow away a 50,000 dTon ship in two salvoes - and (assuming the ship is built around a spinal mount as cruisers usually are) it won't be able to kill very many ships in response, simply because a spinal mount or heavy bay, regardless of how potent, can only kill one ship each.

Note that the balance of power is actually even worse than this, because that cruiser is probably carrying 2+ months of maintenance components, small craft and their crews, and >2 weeks fuel endurance, none of which are required for a small SDB based out of the highport in its home system.

 

[Reynard]

It seems there's debate about what an SDB is and what they are designed for. So far, the majority of designs seem multipurpose maybe for cost efficiency. If you're not going into war then go catch mice. What I hear hinted at is an SDB that is actually war worthy with the naval equivalent to the WWII Patrol Torpedo boat.

I did some quick reading. The PT was designed a ship killer. It was constantly modified to be the honey badger of boats. They relied on stealth such as night attacks or terrain, high speed to get in, deliver the ordinance and get the hell away using smoke screen if necessary and they had the best ship killing weapons available. They hunted support to destroyer sized vessels plus troop transports, never designed to take on full blown capital ships. They were removing the support and defense the larger ships and the navy in general depended on.

I'd say a Traveller PT is based on a small frame and has Stealth, max Maneuver, armor, counter-measures and the nastiest most effective weapon it can carry even if it's limited ammo such as torpedoes plus a small arm for weak targets. They get as close as possible, drop the payload, leave and rearm. Good sensors and intel gets them around the big ships to hit their real targets.

Looks like I have a design project.

 

[phavoc]

To put things in perspective, we're told that most 'proper' navy warships are Jump-4 capable - see the reference in Sector Fleet to "Fleet Manouvrability". This means that a 50,000 dTon ship wastes 20,000 dTons on fuel capacity and a further 2,500 dTons on its jump drive.

Therefore, its actual 'combat systems' volume is about 27,500 dTons - or the same as 55 500 dTon SDBs, it's just hauling 22,500 dTons and 7 BCr worth of dead hull around in a fight.

Yep, if your fleet isn't burdened with having to lug around jump fuel it's always going to be more deadly ton-for-ton (assuming you are talking pure warships), hence the battle-rider concept. But the concept of defenders having a force-mulitiplier (walls, prepared defenses, etc) has been around for a long time.

But like any other battle, when you are the attacker you get the advantage of massing your offensive fire power against the defender's weaker defenses which have to spread out to protect so many targets.

Its equivalent of 55 SDBs with a large, high yield particle beam bay each, puts out a barrage of 495-Particle-Long-9. Allowing for a fair mix of evasion, armour, sensor locks, etc, you can get a barrage with a DM-2 or not far shy, which gives you an average of...pretty much 100% damage.

500 barrage damage is enough to blow away a 50,000 dTon ship in two salvoes - and (assuming the ship is built around a spinal mount as cruisers usually are) it won't be able to kill very many ships in response, simply because a spinal mount or heavy bay, regardless of how potent, can only kill one ship each.

Note that the balance of power is actually even worse than this, because that cruiser is probably carrying 2+ months of maintenance components, small craft and their crews, and >2 weeks fuel endurance, none of which are required for a small SDB based out of the highport in its home system.

Yeah, there's certainly power in numbers! And you are very right that the larger ship has to swat a lot of flies. That's why you have escorts, to keep the pesky little ones off the big guys back while they fight the other guys big uns'.

The interesting thing about Traveller is that they the weapons only scale to X (taking spinal mounts out of the equation), and smaller ships can mount the same class weaponry as larger ones. There isn't a "classic" mix like you used to see on naval ships, where you had the main armament, your secondary armament and then lots of little armament - each class designed to be used against different types of enemies.

I suppose one could argue that the spinal mount IS the defacto main armament of Traveller ships, but since you only get one per ship (and it's not a Wave Motion Gun...), it's hard to apply the same analogy.

 

[Condottiere]

Planetary naval staff will have proportionate numbers and capabilities of SDBs and monitors. That is, if you're not living near the Solomani border, you won't be expecting a battlecruiser to jump in, and in the Spinward Marches, they should be capable enough to discourage the odd pirate and raider.

 

[locarno24]

Planetary naval staff will have proportionate numbers and capabilities of SDBs and monitors. That is, if you're not living near the Solomani border, you won't be expecting a battlecruiser to jump in, and in the Spinward Marches, they should be capable enough to discourage the odd pirate and raider.

Exactly. Whereas in other places to you might look at taking a decomissioned Imperial navy capital warship and stripping out the jump drive as a 'defence boat'.

The interesting thing about Traveller is that they the weapons only scale to X (taking spinal mounts out of the equation), and smaller ships can mount the same class weaponry as larger ones. There isn't a "classic" mix like you used to see on naval ships, where you had the main armament, your secondary armament and then lots of little armament - each class designed to be used against different types of enemies.

It's the armour that's the main issue. Any starship - hell, any small craft if you really want to make a point - can be armoured up to the point that barrages from turret mounted weapons, missiles, and non-nuclear torpedoes might as well not bother, making barrages from bay weapons the primary 'broadside' of a capital ship fight.

 

[Condottiere]

You could set aside a certain tonnage for armour, have what feels like a complex set of calculations determine general thickness, compare that to a chart and you'll find that it scales.

 

[Reynard]

First off, where is this Dragon SDB I keep hearing about?

I've been reading everything I can find about Traveller SBDs and I see a couple obvious facts. The typical SDB is an armed non-jump ship between 100-1000 dtons and the variety seems infinite. The majority of the very few examples are way undergunned for wartime though. They're the analogue to coast guard cutters. The big difference seems to be armor replacing the J-drive space. I assume this means they endure a little longer in a standup fight.

What I don't see in published material are the SDBs specifically designed to take on warships, the ship killers. I recently created one inspired by this discussion and need to compare with appropriate opposition for effectiveness then see what will be the most efficient size. I used PT boat specs for a classic wet navy tactic design. As one article states, "By war's end, the PT boat had more "firepower-per-ton" than any other vessel in the U.S. Navy.". That's what a Hunter-Killer SDB should be.

By the way, I think an analogous wet navy sub operating in blue water would be similar to a stealthy SDB design but jump capable too.

 

[Condottiere]

You can be inspired by any number of real life analogues.

The top of the pecking order should be the battle riders, since it's seems pointless to schlep along anything that couldn't take out a dreadnought by itself.

Somewhere in the lower upper tier anything that could give pause to a battlecruiser.

The lower tiers would have examples like the equivalent of a U-Boot, that opportunistically surfaces to take out a solitary enemy with a single barrage and then disappears. Arguably, smallcraft qualify, if they are optimized for the role.

SDBs probably work best if used in groups and designed as a platform for a powerful offensive weapon, especially if they are intended to do strafing runs, or actually committed to battle.

Shipbuilding programmes tend to be held hostage to economics, interest groups, politics and occasionally, military requirements.