Difference beween Escort Destroyer and Fleet Destroyer?

[Matt123]

400tn? Are we assuming a small ship universe, or are we talking about pirates and privateers?

The OP was looking for reasons for DEs, one of which might be protecting the star lanes from commerce raiders (which may or may not be pirates and privateers). I'm just pointing out that I would happily encourage this by flooding the Imperiums borders with many small commerce raiders. Tracking them down with 1000tn Des is an expensive proposition. I'm also suggesting that while a 1000tn DE will "of course" knock out a merchant, it is overkill, more economic solutions exist and in many cases "driving them back" through causing damage, will suffice.

The same dynamic applies when you send a cruiser fleet raiding. It is not the damage it might cause (exceptions and special missions aside), it is that the other side will need to chase it with larger capital ships, that are now no longer in the main fleet. In addition you will need multiple large capital ships working together to cut off jump routes, if it can be done. No raiding cruiser will willingly take on a battleship if there is an escape option.

You "lose" a cruiser from the front line, the other guy "loses" 4 heavy cruisers or 2nd class battleships from the front line trying to pin you down.

 

[Carlobrand]

The OP was looking for reasons for DEs, one of which might be protecting the star lanes from commerce raiders (which may or may not be pirates and privateers). I'm just pointing out that I would happily encourage this by flooding the Imperiums borders with many small commerce raiders. Tracking them down with 1000tn Des is an expensive proposition. I'm also suggesting that while a 1000tn DE will "of course" knock out a merchant, it is overkill, more economic solutions exist and in many cases "driving them back" through causing damage, will suffice.

The same dynamic applies when you send a cruiser fleet raiding. It is not the damage it might cause (exceptions and special missions aside), it is that the other side will need to chase it with larger capital ships, that are now no longer in the main fleet. In addition you will need multiple large capital ships working together to cut off jump routes, if it can be done. No raiding cruiser will willingly take on a battleship if there is an escape option.

You "lose" a cruiser from the front line, the other guy "loses" 4 heavy cruisers or 2nd class battleships from the front line trying to pin you down.

Certainly the Imperial fleet can spare DEs for hunting more easily than cruisers, but a well-designed DE is a very effective convoy escort, able to fight off those smaller ships while being a very difficult target for the larger ships, therefore able to protect the merchants it is escorting. Ships under 2000 dT in High Guard gain a -2 defense bonus. Maintaining maximum agility and the maximum available computer means the DE can't be hit by missiles of factor 4 or less and will take hits from only 1 in 6 factor-9 missile batteries. Imperial DEs can also carry hefty levels of armor, rendering them immune to beam lasers and energy weapons, very nearly immune to pulse lasers, and only marginally vulnerable to nuclear missiles - which must penetrate the damper, and only 1 in 6 of the missile hits will achieve that. Factor in the fact that their opponents won't have as good computers, and it gets worse for their opponents. A TL14 cruiser with 36 F-9 missile batteries will hit about once in 4 turns on average, a lot of those hits won't penetrate armor, and those that do will nip armor or fuel. The DEs can escort a convoy from jump to landing while under fire from a cruiser, land, get weapons repaired, and then launch to escort ships from planet to jump.

92% of Marches freight is carried on the major and main routes, which amount to 17% of the Marches routes, and many (though not all) of those routes also have significant SDB defenses. It becomes cost effective to assign DEs only to the major and main routes, and only to bridge those high-traffic systems that don't have adequate defenses themselves. For the rest - well, DEs tailored to survive cruiser attacks are not actually the best ships to hunt down raiders. They lack the firepower to seriously threaten cruisers and larger destroyers, and they're overkill for the little 400 dTonners you're thinking of sending in - police cruisers, pocket carriers, and Gazelles are better for the small fry, since you can deploy more for the same cost, while capital ships supported by a network of agile scouts are best to hunt down raiding capital ships.

 

[mike wightman]

The DM for a 100-1999t ship is -1, not -2. The -2 is for smallcraft.
"DE can't be hit by missiles of factor 4 or less and will take hits from only 1 in 6 factor-9 missile batteries." becomes DE can't be hit by missiles of factor 2 or less and will take hits from factor-9 missile batteries 28% of the time.

So you need at least 4 times as many bay missile weapons - either in the form of 4 ships of equal size, or a larger destroyer in the 5-10kt range or better yet a light missile cruiser of up to 19000t.

Which means your 1900t raider is tying up 4-10 times the tonnage of enemy warships trying to hunt you down.

 

[Condottiere]

There are formulas to figure these things out, though you'll forgive me if I don't hit the books to quote the experts.

The British figured the minimum requirement is around seventy cruisers for both trade protection and fleet support, a mix of light and heavy post Great War, the light becoming a separate category during subsequent naval treaty negotiations since they especially needed numbers compared to everyone else, who could have just kept building ten kay heavies that on paper would have overwhelmed the lights on a one to one basis.

Then you have the submarine war, where it really becomes an issue of attrition within a specific time window.

You could add in the strategic bombing campaigns, as well as the more tactical ones meant to take out shipping.

If you had the means to take over territory, you don't really need raiders.

 

[Carlobrand]

The DM for a 100-1999t ship is -1, not -2. The -2 is for smallcraft. ....

Oop, you're right, my bad.

...Which means your 1900t raider is tying up 4-10 times the tonnage of enemy warships trying to hunt you down.

Which means the 1900t raider isn't accomplishing much, since it can't penetrate SDB defenses or the 1900t convoy escort while being 3 or 4 times the size needed to beat up merchant ships plying poorly defended minor and feeder routes and is too small to carry a decent marine complement or fighters to harry those poorly defended ports. Matt's proposition of throwing in a lot of little ships had merit, it's just that they really only affect about 8% of Marches trade. But, to deal with heavier defenses, you need the capital ships. That spinal is about the only thing that's going to make escorts and SDBs ask for help.

An agile 4-600 dT purpose-built raider with a military-grade computer presents almost as much headache for the enemy fleet as an agile 1900t raider. It gets to be like hunting ticks - no, they can't do anything to any warships they encounter, but it takes a surprising bit of effort to squish them, their firepower is quite adequate for making merchants miserable, and they're everywhere.

 

[kilemall]

On the overkill bit, I don't know that the DE/convoy operators would mind, dissuasion means no losses except for time in holding up transit until the escorted convoy is formed.

The economics are not simple cost in/ protection out- there is likely a lot of economics input or military hardware being shipped, or even morale bits like fruitcake for Holiday, whose destruction as final product will invalidate a lot of effort or worse cost time and options.

Another aspect of DEs to consider is that they aren't built to be long serving ships, more war emergency. As such, one option is to build them cheap, and then require a higher percentage of maintenance, or at the end of 10 years maintenance doubles and keeps doubling every 10 years until they are scrapped.

 

[khadaji2002]

IMO, hauling raw resources (ore, basic foodstuffs, metal ingots) would draw less attention for commerce raiders/pirates in all save times of actual war. The real targets would be high-value targets. This does not mean high-credit necessarily.

Kilemall's example is a good one. Target ships carrying goods that carry morale value above and beyond the credit value of the cargo. Goods meant to help celebrate a holiday. Cargos that demonstrate the pirates can interdict government aid (such as vaccines needed by the neighboring planet to fight off the latest plague). The shipment of luxury items being sent to the sector governor as taxes or to honor a long noble term of service.

To hit these kinds of targets the raider/pirate crews would need good intel. In most starports this would be fairly easy if the raiders spent time developing contacts and the like, to track what's leaving the planet. I would think that the first time or two such cargos got hit there wouldn't be a huge uproar from the citizens at either end of such trade routes. However, hit in the same area two or three times the systems are going to start upgrading their response. They'd have to for morale reasons.

Here is where the escorts/system defense ships would come into play. The way jump is set up I can't see many ships being assigned as convoy escorts unless the system being routinely hit cannot host defense ships of its own. I can see most systems putting more SDB/destroyers out near the 100d limit. I would think that most of the ships put out would be tasked with simply fending off the pirates from the trade lanes, allowing commerce to flow. The destroyers (if any such were tasked) would be sent out not only to fend off raiders but to try to find where they're jumping to and hit their base of operations.

My 0.2 Creds worth.

 

[Carlobrand]

...
Another aspect of DEs to consider is that they aren't built to be long serving ships, more war emergency. As such, one option is to build them cheap, and then require a higher percentage of maintenance, or at the end of 10 years maintenance doubles and keeps doubling every 10 years until they are scrapped.

It's a good idea, but we'd need to come up with some rules to implement it. I don't know of anything in canon that I could use as a launching point for coming up with cheap short-lived warships.

IMO, hauling raw resources (ore, basic foodstuffs, metal ingots) would draw less attention for commerce raiders/pirates in all save times of actual war. The real targets would be high-value targets. This does not mean high-credit necessarily.

Kilemall's example is a good one. Target ships carrying goods that carry morale value above and beyond the credit value of the cargo. Goods meant to help celebrate a holiday. Cargos that demonstrate the pirates can interdict government aid (such as vaccines needed by the neighboring planet to fight off the latest plague). The shipment of luxury items being sent to the sector governor as taxes or to honor a long noble term of service.

To hit these kinds of targets the raider/pirate crews would need good intel. In most starports this would be fairly easy if the raiders spent time developing contacts and the like, to track what's leaving the planet. I would think that the first time or two such cargos got hit there wouldn't be a huge uproar from the citizens at either end of such trade routes. However, hit in the same area two or three times the systems are going to start upgrading their response. They'd have to for morale reasons.

Here is where the escorts/system defense ships would come into play. The way jump is set up I can't see many ships being assigned as convoy escorts unless the system being routinely hit cannot host defense ships of its own. I can see most systems putting more SDB/destroyers out near the 100d limit. I would think that most of the ships put out would be tasked with simply fending off the pirates from the trade lanes, allowing commerce to flow. The destroyers (if any such were tasked) would be sent out not only to fend off raiders but to try to find where they're jumping to and hit their base of operations.

My 0.2 Creds worth.

"Loose lips sink ships." What's easy in peacetime is likely to get a good deal harder in wartime, especially as the war progresses and the ports tighten up their security processes, start using false intel and stings to pinpoint leaks, and start making examples of the loose-lipped. There'll be some early successes, or tragedies, depending on which side of the missile launcher you're on, and then things gradually get tougher.

Of course, there's still the problem of penetrating the escorts (or defending SDBs), or the intelligence does you no good. Penetrating TL15 Imperial escorts is pretty challenging. Blowing up a couple of escorts with meson fire might be the best they can manage, which limits effective wartime commerce raiding to the light cruisers and up and leaves smaller raiders taking their chances out in the hinterlands where merchants are less likely to have escort or SDB coverage. Smaller raiding ships in wartime might get more mileage out of bombarding weakly defended worlds.

There's also the problem of timeliness of intel. With information traveling at the speed of jump, knowing a transport's going to launch in 5 days with a load of war-widgets bound for System-X isn't very useful intel unless your raider's already in the destination system - say, hiding out in the outer system somewhere - waiting for the intel to arrive on some agent's ship. Again easier earlier than later, when Imperial intelligence starts getting some successes penetrating networks and using turned agents to lure raiders into ambushes.

 

[phavoc]

The other side of commerce raiding...

For commerce raiding, much depends on the nature of trade for all the various combatants. Using past naval wars, those nations that had the most sea commerce had the greatest need to protect their own merchant shipping.

England has had a large merchant fleet for a long time. Spain did as well. In both instances smaller nations with less to lose found that raiding was both profitable and also disruptive. And starting in the 20th century we saw England as the pre-eminent merchant marine (oddly, at the start of WW2, Norway had a massive 6,000+ merchant fleet). Germany took advantage of this disparity because they could not compete on the high seas, so their raiders did have outsized influence - at least until they were sunk.

However, the issues have typically been one side having more to lose than the other. If you have a single side that has to devote hulls to commerce protection it obviously won't have them to deploy on the front line. So it would behoove any stellar power to ensure it, too, had enough raiders to do the same to the other side. Then the lack of hulls would be equalized and thus be reflected in the front lines.

 

[Condottiere]

Conditionally.

Privateering served three purposes. It kept Spain distracted, it filled the Treasury, and it built up a cadre of experienced commanders and crew.

The English knew that for pure ideological reasons, Philip will eventually turn his attention to the English heresy, so they made hay before inevitable twilight.

 

[Baithammer]

Penetrating TL15 Imperial escorts is pretty challenging.

Pirates are a risk averse crowd, if something fairly big shows up with the target, they'd move along to another target.

Raiders are a different situation entirely and most likely would shadow the convoy while trying to get sufficient resources pooled to eliminate the escorts.

 

[Theophilus]

IMTU: Fleet destroyers are large (10kton) destroyers usually equiped with small spinal mounts used in fleet actions, almost small light cruisers.

Escort destroyer are destroyers specifically outfitted as escorts, mostly with anti-missle/small ship weapons.

 

[Condottiere]

My ratio is about ten to fifteen percent of volume dedicated to the primary armament for a frontline warship.

 

[GypsyComet]

IMO, hauling raw resources (ore, basic foodstuffs, metal ingots) would draw less attention for commerce raiders/pirates in all save times of actual war. The real targets would be high-value targets. This does not mean high-credit necessarily.

In most cases the transport ship is worth more than any but the most exotic or high end finished goods cargo load, and as a flexible transport asset, the ship is *very* valuable. regardless of what it might be carrying on any given trip, an enemy's transport is always worth the effort to kill. They take years to replace.

 

[BlackBat242]

In most cases the transport ship is worth more than any but the most exotic or high end finished goods cargo load, and as a flexible transport asset, the ship is *very* valuable. regardless of what it might be carrying on any given trip, an enemy's transport is always worth the effort to kill. They take years to replace.

Exactly - you destroy one transport, you block all of the cargoes that that ship might have transported over the next 2-3 years (until its replacement is operational)!

 

[Shadowrunner]

Out here on the frontier modern and capable ships tend to stooge around fleets and planets, while the old and expendable are sent out on missions. Social standing plays a factor too in postings. Often merchant navies or accredited individuals are providing the intelligence and patrol function. Leviathan is a great example. Midu Agashaam for example would more likely be found somewhere safe. The old CT ilustrations tend to influen e me, eg Type T.

 

[Condottiere]

It would depend on the importance of the mission; the older ships are expendable, and would be given non critical tasks.

 

[Ex_Pendable]

Exactly - you destroy one transport, you block all of the cargoes that that ship might have transported over the next 2-3 years (until its replacement is operational)!

This assumes conventional ship construction, but Traveller allows for modular ships, where you may have different modules strung together to form the ship. It's faster to build new modules than complete ships, so a damaged engineering module could be quickly replaced.

It would depend on the importance of the mission; the older ships are expendable, and would be given non critical tasks.

Or used as a perimeter screen, giving newer ships a chance to respond while the older ships are being attacked.

 

[mike wightman]

That's rule set dependent.

If you look at the rules in CT TCS for repair and refit of ships it is expensive and time consuming and does not reflect just swapping out modules.

Go to TNE and the Clipper and replacing modules would be trivial in comparison.

 

[BRJN]

Commerce Raider Option 5
Damage the freighters but don't destroy them.

An MS with a hole in its J-Drive won't be transporting cargo anywhere. Put a hole in the staterooms and the crew might decide to call it a day (or demand extra pay for the discomfort). Break the M-Drive and the escorts or Planetary Traffic Contro! has to mount a rescue mission. Any which way, it is sand in the gears of his war machine.I

Use a Q-ship mocked up to look like his Subsidized Merchant for greater morale effect.