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Pearls of Weber

A collection of posts by David Weber containing background information for his stories, collected and generously made available Joe Buckley.

FTL LACs

My advice here is to forget the notion. It isn't worth it. There's a reason why an unarmed courier boat with a minimal crew still masses around 40,000 tons, and that reason is alpha nodes for Warshawski sails coupled with the mass of a hyper generator, which is large. For a Shrike-class LAC, figure that about (I am deliberately refusing to share my hard numbers with you here) 20% of its total mass is in engines--Beta² nodes, emergency reaction thrusters, inertial compensator, etc. For a hyper-capable DD (which, remember, is 4-4.5 times the mass of a Shrike) the same figure would be around twice that, and a DD is basically built around the same size hyper generator and alpha nodes as a courier boat. So figure that an LAC would spend 4,000 tons on its sublight propulsion alone and that a DD would spend around 34,000 tons. There would also be the additional hull required to fit those systems into (which would be large, because it would have to envelop the entire length of the Shrike (the reason ships have two impeller rings is that it is the alpha nodes which must be placed near the ends of the hull), and your 20,000 ton Shrike is going to start turning into a 54,000-70,000 ton Shrike. Nor would a new-build DD give up that much of an accel advantage over its Peep counterparts compared to a LAC. A Shrike can pull around 620 g; a 3rd generation, 90,000-ton RMN DD can pull roughly 600 gravities at full military power, which is only about 20 gees lower. While this would be significant in a foot race with a Shrike, it would not be all that significant in comparison to a Peep destroyer of the same mass which, with the old-style compensators, could only pull around 519 gravities. It may be argued that once the Peeps finally get hold of the new compensators, the DD's accel advantage will disapper. Well, so will all but 20 gravities of the Shrike's advantage.

In addition to these purely technical considerations, I would think that the RMN would reject a "sleeve" approach because of the tactical dangers it would represent. Bear in mind that I have not read all the posts on this topic, so someone may have come up with a clever suggestion I don't know about, but the greatest weakness of the entire system would seem to me to be that having come out of hyper and undocked from one's sleeves, one has to leave those sleeves somewhere. If, in fact, the enemy doesn't know when you arrived, or where you went, or where you dropped them off, they should at least still be where you left them when you need them. If the enemy does have the least notion where you came out of hyper and he has any mobile forces in the area, they will simply lie there like a hole in space until your Shrikes are way far in-system, then amble over and, with leisurely, unopposed precision fire, reduce your sleeves to drifting wreckage, thus effectively marooning your LACs in the system in question. Even if they only have forces out beyond the hyper limit, they can be told--even with light-speed communications--where to look for your sleeves if you were spotted by a sensor platform in passing or any of several other things which could give away your general arrival locus. At that point, Mr. Peep pops into hyper, comes out right at the hyper limit behind your LACs (which are now too far away to intervene) goes active with his radar, locates the sleeves, and wipes them from the face of the universe. Any Admiralty is going to have very serious qualms about any system this vulnerable to destruction even if it decides that the enemy will find them only by a fluke. Flukes, after all, happen in warfare, and if this one occurs, the consequences will be the total loss of your scouting force. Your LACs might try coming in from extreme distance to minimize the chance that their hyper footprints will be detected. This would allow them to undock from their sleeves at any point along their approach course they wish. But they could still be detected incoming, and the enemy could still use units out-system of them to move in along the hyper limit and wait for them. All the interceptors would have to do would be to reach a point on the periphery of the hyper limit at which the LACs will cross, then camp there and wait for the LACs to enter engagement range. Admittedly, they could also do this to a hyper-capable DD, but the difference is that if the DD spotted them (and I, for one, would be using lots of recon drones to watch for lurking cruisers), the DD could alter course short of interception, cross the hyper limit elsewhere, and be off and away into hyper space immediately without having to figure out how to reach the waiting sleeves (now quite possibly on the far side of a hostile force which is hyper-capable and therefore able to attempt micro-jumps to intercept LACs someone else entirely may be tracking for them).

Even if the initial location of your sleeves is not known to the enemy, your LACs will have to withdraw to rendezvous with them before they can leave for home. That means they have to backtrack the way they came. An astute enemy CO will realize this and do his damnedest to track/intercept your LACs on the way back. He may have only a 10% or 15% chance of pulling this off, but if he pulls it off at all, at least some of his units are very likely to beat you to the sleeves (assuming that you have come in past his outermost units to scout and are now forced to decelerate back towards them). If they do, they wipe them out, and you're stuck. Even if he doesn't manage to do that, he'll be given a chance to intercept and engage your guys as they pass by. A ship with its own, integral hyper capability, OTH, doesn't have to backtrack. It can blow on out of the inner system on whatever vector looks best to it, and it can hyper out the instant it crosses the hyper limit (assuming its velocity is no greater than .3 cee at the time), with no need to rendezvous, dock, bring the alpha nodes on line from a cold start. etc.

Rather than adopt some complicated, tactically dangerous two-part system for a Shrike, the RMN is far more likely to go for a new-build DD which may be smaller than current DDs, thus bringing platform costs down even closer to the cumulative cost of a "sleeved" Shrike, and give it some "Shrike-like" characteristics. With the new missiles, for example, they may (may, I say!) decide to delete the conventional chase armament, move the missile tubes around to the broadside, and put a really powerful spinal mount in place of both the chase tubes and the present chase energy weapons. They may very well also add a bow wall, which would permit the DD to pull a Shrike-style "strafing attack" on larger, heavier ships. They may be able to incoporate Beta² nodes into the design, to free up more internal space for other nasty tricks, and I'm sure they would include upgraded EW capabilities. But they will also give it integral hyper capability, and they will continue to visualize it as a generalist and not a specialist.