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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.

Reliant-class battlecruiser ship layout

All right, Guys (in the best non-sexist, gender nonspecific sense, of course.)

I realize that we've been talking a lot about black holes, singularities, and event horizons here lately, but I'd like to get back to an earlier point in the thread when people were talking about hull forms and etc., for HH's universe's warships and/or freighters. Bearing in mind that my talents like in the verbal skills area, not the graphic (else I were an artist, not a writer), I will do my humble best to Reveal All (or at least a goodly portion of it) by giving you a somewhat more detailed description of HMS Nike than appeared in The Short Victorious War or Field of Dishonor (since, after all, the exact hull form of the vessel never became especially important to events in either novel).

To begin, assume a cylinder 1,630.2 meters long and 206.25 meters in diameter. Put said cylinder in a lathe, kick that puppy on, and lay a chisel to it. Beginning at a point 163 meters from either end, cut a groove 41.25 meters deep into the cylinder (that is, the cylinder diameter at the deepest point of the groove will be approximately 121 meters). This is the impeller ring, and is about 10 meters wide. (It would be narrower on a smaller ship; wider on an SD.)

Leaving the cylinder ends alone for the moment, cut a straight taper from the aft edge of the forward impeller ring (173 meters from the end of the cylinder) to a point 540 meters from the extreme forward end of the cylinder. In the course of this taper, you will go from a diameter of 121 meters to the original full diameter of 206.25 meters. Then cut precisely the same taper working forward from the forward edge of the after impeller to a point 540 meters from the extreme after end of the cylinder. Finally, go back to the "full-beam" midsection and "flatten" it into a more oval form with a maximum depth of only 185 meters but a beam of 206.25 meters, and you have the rough form of the main body of the vessel.

Next go back to the ends forward and aft of the two impeller rings. (Both of these are going to have the same form when we're done, so we'll deal only with the forward end for simplicity's sake.) Move forward approximately 81 meters from the forward edge of the forward impeller ring. The portion of the original cylinder between this point and the impeller ring will retain its full original width [which, for those of you who haven't already deduced it, is the extreme beam of the vessel ;-)]. Forward of that point, the "hammerhead" will taper vertically (uniform taper, top and bottom) in a flattened wedge shape squeezing down to a final "depth" of approximately 60 meters, where it ends in a flat, perpendicular face 60 meters deep and 60 meters wide. The sides of the hammerhead cut inward on an arc from the 81 meter point to meet the side edges of the bow's vertical face.

Nike's broadside weapons are located on two decks. Unlike Peep ships, which tend to segregate missile and energy weapons to simplify magazine, ammo handling, and power run considerations, the RMN intersperses missile tubes and energy weapons in order to keep a single lucky hit from taking out all (or at least a large percentage) of any one type of weapon. Accordingly, Nike's upper deck is armed as follows:

where M=Missile Tube, L=Laser, and G=Graser. (The missing missile tube on the lower deck was ommitted to provide additional boat bay space for a flagship.) The chase armament (bow and stern) consists of a single laser in the center of the bow's face, flanked by a pair of grasers. The missile tubes are arranged in vertical pairs, one on each side of the bow in the curved face of the hammerhead. The forward gravitic array is located in the center of the tapered slope to the bow's face, with a pair of phased array radars located aft of it at the upper "corners" of the taper. Each radar array is accompanied by a lidar installation, and the ventral side of the hammerhead carries the same instrumentation.

The main broadside gravitic arrays (the largest arrays on the entire vessel) are located at the exact midpoint of the hull on either side, equidistant (vertically) between the two main weapons decks. The ship also mounts two energy torpedo launchers, which are located one each just aft and just forward of the gravitic array. The ship is well provided with radar and lidar on the broadside, with paired arrays located at the upper curve of the hull (that is, above and below the armed decks, respectively) and approximately 525 meters from the extreme bow to the midpoint of the radar arrays.

Boat bays are traditionally cut into the "belly" of the ship, although a few classes with dorsal boat bays have been built by the RMN in the past. Nike, however, adheres to the traditional practice and mounts most of her com lasers and a few secondary sensor arrays along the "roof" of the hull.

Anti-missile point defense laser clusters are mounted on a separate deck which is not normally considered a "weapons" deck, since its function is purely defensive. In Nike's case, this deck carries a total of 31 individual laser clusters in each broadside. Counter-missiles are launched both from from standard missile tubes and from smaller tubes (12 in each broadside) along the upper "turn of the hull" as it flattens. Counter-missiles are much smaller than ship-killer weapons, however, and those fired from a ship's main tubes are usually launched in cannisters containing from 3 to 4 missiles each (the latest capital ship missile tubes can handle 5-missile cannisters). In some lighter classes, there are no dedicated missile-defense launchers at all and all counter-missiles are fired from the main tubes.

ECM emitters and similar systems are mounted wherever function demands and space availability permits, and are extremely vulnerable to being ripped up and moved in the course of a refit. Personnel locks and small craft auxilliary docking ports are also located at intervals over the entire hull of the vessel, although RMN ships normally include far fewer such locks and ports than Peep designs do.

The major difference between ships of the wall and BCs, CAs, and lighter units is that the big boys' hull midbodies tend to have more cylindrical and less flattened cross-sections. Their design parameters emphasize filling out the maximum possible amount of hull volume, whereas the lighter combatants shave volume to save mass and achieve marginal acceleration improvements from a given impeller strength. Ships of the wall are intended to carry the maximum possible armor and weapons loads, and they accept a certain slow-footedness as the price tag for doing so. The main difference between most freighters and warships is that, since freighters have no need for chase armament, their hulls do not normally flare back out to the maximum beam ahead and astern of the impeller rings. Instead, bulk carriers tend to have blunt, flat ends with huge cargo doors, or else to use the space ahead and astern of the rings as hangar space for heavy-lift cargo shuttles.

The impeller rings of any military starship mount a total of 24 nodes: 8 alpha nodes and 16 beta nodes. The alpha nodes are mounted at 0, 45, 90, 135, 180, 225, 270, and 315 degrees. The beta nodes are mounted every 15 degrees between the alpha nodes. In terms of size, an alpha node is about three times as large and massive as a beta node; in terms of the generator support required, the difference is more like six times as great, but a beta node provides about half as much power to a standard impeller wedge as an alpha node does. Thus each alpha node provides about 6.25% of a wedge's full power and each beta node provides about 3.13%, so that the alphas and betas as groups each provide 50% of the whole. (Actually, those values are halved for the full power of the wedge, since both impeller rings combine in a full-strength wedge.) The 8 alpha nodes, however, suck up as much mass as 48 beta nodes would, which is the reason beta nodes are used. It is the alpha nodes which contain the Warshawski sail components, though, and a ship cannot generate a Warshawski sail without at least 8 of them. It is possible to run a node at greater than 100% of rated capacity under emergency conditions in order to get back some of the power lost when other nodes are knocked out by combat damage, but this is a risky procedure and not one to be undertaken lightly. Freighters may sometimes carry fewer beta nodes, or even none at all. It is extremely uncommon for a ship to mount no beta nodes, but it is not unheard of, either, since cargo carriers seldom carry the inertial compensators to permit them to make full use of a "full powered" wedge, anyway.

Obviously, the big difference(s) between LACs and hyper-capable ships is that the former do not have Warshawski sails (or alpha nodes) and hyper generators. Omitting these two items allows a tremendous savings in internal volume which can then be used for other things, like additional weapons. In addition, the usual LAC has a crew of no more than 16-25 men and women and vastly lower life support requirements than even a destroyer with a company of 300-350, much less a ship like Nike with a company of over 2,100.

For those of you who have been asking, the endurance of the average LAC is on the order of 60 days, and the primary limiting factor is reactor mass for its fusion plants. (However, that particular limiting factor is about to change due to something else Those Sneaky Graysons have been up to. ) Reactor mass is also the primary limiting factor on the endurance of larger ships, but they do not require their onboard plants when riding a grav wave (see the appendices to the new anthology) so they actually increase their endurance by spending more time making hyper voyages. Endurances vary widely from design to design even within a given general class (for example, Nike has a designed n-space endurance of approximately 130 days between refuellings because the RMN wants its BCs to be long-legged and have good time on station [or, conversely, good time raiding someone else's station]; the Peeps' Sultan-class has a designed n-space endurance of only 95 days between refuelings, because their designers expected their BCs to operate in conjunction with the main fleet and chose to trade fuel mass for additional magazine space. The newer Peep CA and BC classes have much longer logistical legs than the Sultans, however.)

For their sizes, DDs and CLs have the most "bunker" space of all, but the much greater mass of DNs and SDs mean that ships of the wall have much greater absolute bunkerage despite the fact that they dedicate much less of their total hull volume to providing it. In an emergency, lighter units can refuel from a capital ship "mother ship," but every task group or task force dispatched for operations outside logistical support range of a Fleet base is accompanied by a Fleet Train containing tankers and (usually) ammunition colliers and repair ships and (frequently) accompanied by a dedicated hospital ship, as well. (Under the "Rules of War" which existed prior to the Havenite Wars, these support elements were immune from attack, but that particular gentleman's agreement went out the airlock as soon as the RMN and the People's Navy realized they were fighting one another for their very survival, so it has become customary to provide powerful escorts for the Fleet Train whenever possible.)

Planets with local defense fleets built solely or almost solely around LACs also tend to build a "tender" class of LAC--indistinguishable in terms of mass, acceleration rate, speed, etc., from their warships but basically nothing but huge, mobile gas tanks which serve as tankers for their armed sisters. With such units to support it, a LAC-oriented navy can cover an amazing amount of ground for an equally amazing period of time. Of course, whether or not a LAC wants to encounter an Op Force SD is another matter entirely.

There!

Now, I ask you all to remember that it's late as I type this and that my proofreading may have come up short in a place or two. In other words, there could be Errors! In addition, I remind you (modestly, of course) that I am God in this universe, and that I may be overtaken by some wild impulse to change the laws of physics, in which case all my naval engineers are going to have to go back and design changes into their ships. But there have been enough questions out there, that I decided I would go ahead and put this additional information out there for you.

Hope you enjoy it.

Ciao,

David