This week, we’re going to have a bit of fun. We’re going to take a look at a science fiction ship design – the eponymous Battlestar Galactica – through the lens of some ship design principles developed for early dreadnoughts. We’re going to be talking about gun position.

We want to start by actually identifying the main battery on the Galactica (and others of it’s class, the Jupiter-Class in the lore of the series) and noting the gun positions. This is actually quite difficult in the show – the shaky cam and use of close-ups often makes it hard to know exactly what part of the ship you are looking at when any of the batteries fire. Fortunately, the (apparently canon, from what I can tell) strategy game Battlestar Galactica: Deadlock provides us with not one but two models of the Galactica’s class (one pre-refit, one post-refit; the latter corresponds to the version seen in the show) from its period of active service, which let us see exactly where the batteries are. The initial configuration looks like this:

Jupiter Mk1. Forgive the UI elements in these screenshots, I had to grab them quickly.

While the post-refit configuration (the one that appears, with minor modifications, in the show) looks like this:

Jupiter MkII. I have to admit, I find it hard to believe that such a complete remodel – removing one of the connecting pylons to the flight-pod, for instance – would be done as a refit, rather than launched as a complete second class. Then again, if you look at the cold-war refits of late WWII US carriers, like the USS Midway (CV-41), they made fairly dramatic changes to the flight-deck layout.

The latter clearly has a bit more firepower and a somewhat slimmed down design, but the essentials of the gun layout follows the same basic system. The largest concentration of firepower is in the dorsal gun turrets (on the upper-side of the ship), in two sets of four double-turrets arranged in squares, though the heaviest guns are the front-mounted turrets, slung underneath the ship’s bow in a pair of double-turrets. Those guns are called ‘door-kickers’ in the fiction, though the traditional name for them drawn from the sailing-ship-era would be ‘bow chasers’ (a subset of ‘chase guns’ more broadly), since they are not really part of the main battery. Another, smaller set of heavy guns is set below the ship (ventral), but is not part of the dorsal battery, since the two generally cannot be directed at the same targets (the ventral guns cannot elevate enough and the dorsal guns cannot depress enough, in part because of the placement of the flight pods).

Dorsal mounted guns on the Mk1 Jupiter Class

Finally, there is a set of smaller, more rapidly firing point-defense guns arranged on the flight-pod itself, covering the port and starboard respectively. In the game, these guns are the ones responsible for flak barrages, though in the show we also see the guns of the main battery participate. That’s actually not entirely crazy – dual-purpose anti-ship/anti-air guns were deployed on many WWII era surface ships, with even the massive 18.1″ main battery of the Yamato-class being able to fire an anti-air shell – admittedly one that, like most Japanese AA in the war, was of sharply limited utility.

Dorsal mounted guns on the Mk2, reorganized into sets of four, as with the ventral guns. Oddly, the firing positions are recessed into the ship’s hull slightly, which would make the firing angles even worse.

Now, it is true that battlestars as shown in the series have an additional set of weapons: the fighters contained in their two flight pods (sidenote: paired, unconnected flight pods seem like they would create really awful storage and fire-prevention problems for munitions and fuel). But I think it’s fair to say that the primary armament of the battlestar is its main guns. It is quite clear in the series that Colonial Fleet doctrine is to close into range of the heavy conventional batteries and then batter enemy ships into submission – indeed, the combat air group a battlestar carries is very poorly adapted to engage capital ships by itself, as it features no dedicated bomber (the Raptor can do the job, but is really a repurposed scout ship, not a bombing specialist).

Problems

So what is wrong with this layout? The main issue (and this becomes painfully clear when playing the game, rather than watching the show) is that the firing arcs of these guns are terrible, for two separate, but important reasons.

The first is the firing sweep the guns themselves have. The rearmost cluster of dorsal guns are at least partially obstructed by the engine housing in both versions of the ship (more so in the Mk1) and all of the dorsal guns are blocked from firing low and forward by the bow section, which is ‘taller’ than the mid-section where the guns are mounted (this is worse for the Mk1 than the Mk2, but they both have the problem). The ventral guns have all of these problems, but worse, most notably in the ventral gun clusters on the Mk2, which cannot fully depress its guns because they have been, for some inexplicable reason, placed in a depression in the hull.

As an aside: I find the bow-bulge an unlikely design problem. The bow section of a Battlestar doesn’t contain the main weapon system, or the drive system (either FTL or sub-light), or anything for flight operations, which is to say that it is neither the primary weapon system, nor the primary propulsion system. It mostly seems to house crew and command spaces. Looking across naval design over the centuries from oars to sails to nuclear reactors, one of the few constants is that the overall shape and profile of the ships are dictated by propulsion and armament (with crew facilities essentially jammed in ‘wherever they fit’). So it is a bit baffling what in the bow section is so important that it was worth over-sizing the bow and thus partially obscuring the main battery to fit in. Speaking from historical designs, anything in the bow section is likely to be compromised to preserve the main battery’s firing angles.

This gun sweep problem is further compounded by the clustering of the guns themselves. While the clusters will work fine if firing ‘up’ or ‘down’ relative to the ship’s orientation, any relatively flat firing trajectory leaves them blocked by each other – that is, the front guns in a cluster cannot fire backwards and the port guns cannot fire starboard and so on. Chances are, the firing ‘deadzones’ are significantly larger than they appear; I’m not clear exactly what the tech is (if these are railguns or traditional chemically propelled guns), but it clearly shows muzzle blast on firing, so a ‘near miss’ of a friendly turret is still going to blast them with hot gas or other firing debris. As we’ll see in a moment, this sort of design issue was present in many early dreadnoughts, and I can’t imagine the vacuum of space would make it any better – on the upside, there would be no pressure wave, but on the downside, that would mean the gas would arrive to the back of the friendly turret with all of its velocity and nearly all of its heat.

Screencap of the show (this is actually the Pegasus, I think) showing the muzzle blast quite clearly.

The second problem is those firing arcs taken together: there is effectively no angle at which a Jupiter-class battlestar can actually bring most or all of its firepower to bear on a large enemy target. No matter the angle of enemy attack, a significant portion of Galactica‘s guns have quite literally nothing to do. If the target is level and in front of Galactica, only the bow-chasers can fire, but they cannot fire if the target is below or above and only half of them can fire to either port or starboard. Targets on the broadside and level with the flight pods can only be engaged by half of the dorsal and ventral guns (or less, depending on the angle), while targets above Galactica may take the full brunt of the dorsal battery but nothing else.

(As a side note, experienced Deadlock players may note that there is a small window where distant targets which are – relative to a Jupiter – in front and slightly above, may be engaged by both the door-kickers (which can elevate, if only slightly, from the ‘waterline’) and the dorsal battery, but (at least in my experience) that zone is painfully small and hardly seems an intended part of the ship’s design.)

I suspect that the gun positions here were arrived at for cinematic reasons, of course. In shot composition, relative height often indicates power. By having Galactica‘s guns mostly mounted on top, Galactica can be repeatedly put in scenes where it is ‘below’ Cylon adversaries, which I suspect was an intentional effort to visually display the extreme power imbalance between the humans and Cylons. Which is a pretty solid reason to set the ship up this way for a TV show and it works very well in the show to create very dynamic and dramatic combat scenes.

But of course, we’re here for pedantry, not sound visual design. And so we turn to our second section: how was this handled historically, or

What Galactica can learn from South Carolina (BB-26)

Many of these same sorts of issues – what sort of main batter to have, and where should it go – bedeviled naval design in the late 1800s and early 1900s, both before and for the first few years after the development of HMS Dreadnought (launched 1906). Now, there were quite a lot of factors that played a role in the emergence of Dreadnought and the entire ship-type that was named after her; the development of the dreadnoughts was itself a product of the complex interplay of developments in gunnery, armor and steam propulsion, with naval designers attempting to navigate the trade-offs between the three.

But here I want to get at two key ideas: what does it mean when we describe Dreadnought as all big gun and how are all of those big guns are laid out.

To explain the former, we have to actually begin with pre-dreadnoughts (which obviously were not called that in their day – they were just called ‘battleships’). These ships tended to have mixed batteries of guns in a wide range of calibers. The reasoning was that the smaller guns could fire more rapidly and so more successfully engage smaller, faster targets (like torpedo boats), while the big guns were necessary to engage other battleships. These were classed as the ‘primary’ battery (the big guns, mounted in turrets) and a ‘secondary’ battery (the fast-firing smaller guns, usually mounted in casemates); some pre-dreadnoughts also mounted an even smaller ‘tertiary’ battery. Within these batteries, some pre-dreadnoughts mixed calibers as well, since different guns would be at different effectiveness against different targets (as well as for availability concerns, e.g. the Japanese Satsuma class). I find pre-dreadnought design fascinating even though it was a developmental dead-end.

Via Wikipedia, HMS Majestic (1895) as diagrammed in Brassey’s Naval Annual (1902). Note the extensive secondary battery contained in casemates along the side of the ship, compared to the far more limited main batter contained in the two turrets.

(As an aside: one thing Galactica keeps from the pre-dreadnought era is the use of casemates. A casemate was an armored wall along the side of the ship which would house the secondary guns. The armor of the casemate made these positions more protected than if the guns were just placed, unarmored, on the deck, but casemates often had sharply restricted firing angles (particularly for elevation). Casemates steadily vanished after dreadnought, with the secondary battery – increasingly (post-1920) in an anti-air role – moved to small turrets mounted on the upper decks. But Galactica’s point-defense turrets are mounted in what appear to be effectively casemates, projecting out from between the structural beams that support the outer armor layer. Compared to modern close-in weapon system (CIWS, pronounced see-wiz) mounts, the firing angles for those point-defense weapons are not very good).

In the first half of the first decade of the 1900s, a combination of developments lead towards the development of the all big gun battleship, the first of which was Dreadnought (and thus subsequent all big gun battleships were called ‘dreadnoughts’). Better loading systems and range-finding had improved accuracy (especially at long range) and rate of fire on the big guns, reducing the dependence of fast-firing secondaries (whose duties were, in many cases, offloaded onto escorting cruisers anyway), while improvements in battleship armor made it increasingly clear that anything less than the heaviest artillery was likely to be useless. Since all of the work was likely to be done by the main battery, it made sense to prioritize it more heavily.

A single, uniform main battery of big guns also greatly simplified fire control and direction, because you were now working a single set of guns with identical range, muzzle velocity and firing characteristics. While a more limited secondary battery was kept, the primary focus of Dreadnought‘s design was the main battery, and on the assumption that the main battery, working through a single fire control system, would be focused on a single target. Of course a uniform shell-type over the main battery also makes logistics quite a bit easier as well.

Via Wikipedia, a ship plan for HMS Dreadnought (1906). Note how the firepower is concentrated into the main battery, in the form of five double-turrets. This is what is meant by an all-big-gun design.

Now the question is: where do all of those big guns go? There are a lot of really fascinating designs in the early years after Dreadnought and in terms of main battery layout, Dreadnought herself is less a final version and more an intermediate stage. Dreadnought cannot face all of her guns in any direction – of the five turrets, only four can fire to port or starboard (the two wing turrets being the problem here), only one turret can fire directly aft (due to the placement of the rear tower). In theory, three turrets can fire forward, but in practice – remember I said we’d come back to this – actually firing the wing guns directly forward was likely to blow out the conning tower (whoops…).

Early dreadnought designs attempted a variety of gun-layouts in an effort to allow for maximum firepower to be concentrated on a single target. Early German designs, like the Nassau– and Helgoland-class used a ‘hexagonal’ layout, which allowed them to mount more guns than Dreadnought, but it didn’t allow them to bring any more of those guns to bear on a single target – the layout was abandoned because it increased the weight of the hull without any real advantage in deliverable firepower.

Via Wikipedia, the gun layout for SMS Nassau (1908), showing a hexagonal gun layout, which allows for fitting a lot more guns (six turrets!) in the available deck-space. Inferior firing angles, however, means that there is no firepower advantage compared to Dreadnought’s turret layout – but the considerable weight of the extra turrets comes at a cost in armor and speed.

Another layout was the (crazy, but also kind of awesome) zig-zag layout of ships like HMS Neptune. Neptune could, conceivably bring all of its guns to bear either port or starboard – the staggered arrangement meant that they didn’t obstruct each other. But it also meant that the turrets amidships would have to fire through the upper-works; in practice, this was found to do significant damage to the ship – the same blast-damage problem we saw earlier with Dreadnought‘s wing guns.

Via Wikipedia, showing the gun layout for HMS Colossus (1911) from Brassey’s Naval Annual (1915) showing the zig-zag placement of guns (the same layout as the Neptune). The upper structure would arc over the guns set amidships to allow them to potentially be turned to fire over the ship to the opposite side.

(As an aside: the other problem with layouts set with heavy wing turrets is that they tend to make the ship unstable because they move so much of the weight away from the ship’s centerline. I’m not sure, for a space-ship, how much this would be a concern.)

The solution actually came from the US Navy from an odd direction: Congress. No, I am not kidding. The US Navy had been having the same set of realizations that led the British to Dreadnought, and so in 1905, they went to Congress asking if they could build some fancy new battleships too (Dreadnought was well under construction by this point). Congress, however, was about done with the Navy – they had just built and launched six Connecticut class pre-dreadnoughts (remember though, they were just ‘battleships’ at this point), several of which weren’t even done yet and already the Navy wanted a new ship class? So, in an effort to hold down the cost, Congress demanded that whatever the navy built, it had to be 16,000 tons or less.

Dreadnought, to be clear, as 18,120 tons. So weight would need to be saved. Under those kinds of displacement constraints, having turrets that didn’t do anything was hardly an option, meaning that optimal firing positions were vital to be able to get a ship that could stand up to a Dreadnought at a lower displacement. The solution was superfiring.

No, that doesn’t mean ‘firing better’ but rather (following the Latin) firing over. The South Carolina-class would have two turrets forward and two turrets aft, in each case with one turret firing over the one in front of it. The long barrels would put the muzzle blast safely out in front of (most of) the turret-housing of the lower turret. As an added bonus, in some designs, both turrets in a group could protect their magazines and works with a smaller armored ‘citadel,’ which also saved weight. This appears most famously on the absolutely hideous looking (but fairly effective) Nelson-class of British battleships (c. 1927) which had three triple-turrets, all set forward together to save on weight to keep the ship under the limits of the Washington Naval Treaty.

Via wikipedia, the deck and armor layout for the USS South Carolina (BB-26) from Brassey’s Naval Annual (1912), with the super-firing guns. Note how the super-firing position allows the design to conserve armor (shown by the dark shading)

So while Dreadnought had 5 double turrets could put 4 to each broadside, 1 to aft and 1-3 fore, the South Carolina with just four double-turrets could put all four to either side, 2 to the aft and two to the fore, without any danger of accidentally blowing out her own conning tower. Now, there were some challenges for superfiring gun arrangements – taller turrets meant moving more mass up on the ship, bringing the center of gravity up and potentially destabilizing the entire ship. That, in turn, put a sharp limit to the number of turrets which could be ‘stacked’ (typically just two). Which was just as well, because it rapidly became apparent that – forced to choose between more guns and bigger guns – bigger was generally the best option.

While it took a few years to fully catch on, for battleships, superfiring gun layouts eventually dominated battleship design, because it allowed the ship in question to concentrate all of its big-gun anti-capital ship firepower on a single target.

Re-imagining Galactica

Keeping our historical battleship design in mind, we can revisit Galactica. Now, it is perfectly fine if Galactica’s secondary battery (intended to engage fighters and provide point-defense against missiles) is split all over the ship for coverage. But the same factors – weight of fire, ease of fire control, mass-and-space savings – that lead to the development of uniform caliber, superfiring battleship main batteries are all at play here.

The exact positioning of that main battery would depend very significantly on the intended engagement angle. Rather than spreading the main guns all around, the ship would be planned with a single angle that most – if not all – of the main battery could focus on a single target. For a ship moving in three dimensions (instead of two) there are really three options: an angle perpendicular to the ship’s primary direction of acceleration (essentially ‘broadside’ but would also cover dorsal and ventral angles), an angle opposite to the primary direction of acceleration (aft) or with the acceleration (fore).

In the case of the Galactica – a ship armed with mostly shorter range conventional munitions, whose primary threat consists of large enemy carriers operating at long-range using strike-craft and missiles – I’d think a forward engagement angle would be the obvious choice. While Galactica is mostly engaged in time-buying defensive delays in the show, she wouldn’t have been designed for an escort role; Galactica was originally a front-line heavy combat ship, built to engage Cylon capital ships. Given that, it seems likely that Galactica would be firing while attempting to close with their targets – ‘charging’ while firing.

(An aside: Now, I’m assuming the physics and motion model that we see in the show and its associated games. While smaller ships in Battlestar Galactica are often shown to turn on their axis (flying one way and pointing another), larger ships seem to generally stay oriented towards the direction of their velocity. More to the point, ships tend to accelerate in the direction they want to go, rather than following orbital paths or transfer orbits, so I am going to assume that Galactica is likely to face-and-charge an opposing ship, rather than the more complex intercept trajectories you might get from orbital mechanics.)

So how might Galactica‘s main battery be moved in order to improve the firing angles? I think the solution lies in a superfiring gun layout. One of the main limits to superfiring gun positions on a battleship was that they raised the ship’s center of mass, resulting in instability – that’s why a ship like the HMS Nelson can’t elevate its third turret above the other two. But a ship can’t capsize in space (although you would want the vector of acceleration to pass trough the center of mass, so that turning on the engines doesn’t rotate the ship), so you could superposition quite a lot more of the battery. Instead of mounting the guns in clusters on center of the ship, they could be mounted on the bow section, in superpositioned mounts (presumably with crew and command facilities moved to the center section of the ship).

Via Wikipedia, HMS Nelson (launched 1925). In order to save weight to comply with the Washington Naval treaty, all three turrets of the main battery were concentrated forward so that they could share armor and magazines. The design was fairly successful, but oh boy, it is ugly.

If I could make further design changes, rather than the current layout of a lot of mid-sized guns and some point-defense guns, I might seek to compress the main battery into a handful of much larger emplacements (super-positioned on the bow) while expanding the number of smaller emplacements mounted in dorsal or ventral positions (ideally with nice, big firing arcs). The center section might also be made taller, but not so long (so that it isn’t obscured by the bow or aft) to allow better firing arcs.

Conclusion

This bit of design silliness is by no means limited to Battlestar Galactica. If anything, the firing angles on Imperial Star Destroyers from Star Wars are even worse. The ship is shaped like a diamond, which promises lots of space for superpositioned guns, but instead the main battery is set to either side of the main tower, with the turrets lined up such that they make it impossible for all of the guns to be fired forward.

One thing I haven’t discussed here, but is closely related to the intended angle of engagement is armor placement. Armor is almost never uniformly thick on any armored vehicle, be it a warship or a tank – instead, armor is carefully shaped around key assumptions on the likely angle of attack as well as what parts of the vehicle are most important. You can see this quite clearly in tank design, where rear and top armor is typically much thinner than front or side armor. We’d expect the same consideration for a ship like Galactica – and in Deadlock, this is actually the case – the broadsides and front arc are far more heavily armored than the rear, top or bottom.

Now, does all of this matter? Honestly, no, not really. Certainly, I find that making designs in speculative fiction more plausible by leaning on historical design philosophies can make the fictional world itself feel more real which can improve the storytelling.

But I think the real take-away here is an obvious but oft forgotten one: while it is easy to critique the designs of historical weapon systems, they were in fact the product of quite a lot of smart people working hard to solve difficult problems. “Doing it all” was never an option – every bit of added firepower or armor meant more weight and thus less speed (or, in space, a worse thrust-to-mass ratio). In turn, that meant for a given engine and speed requirement, every bit of armor meant less firepower, and vice versa. Having lots of small guns meant fewer guns in the main battery.

Often when we see designs that are clearly compromised in some way – like, famously, the M4 Sherman – we attribute this to ‘bad’ design, when it is often in fact the product of forced compromises in the design process between competing and incompatible design goals.

(Clarification note: I think a few folks may have misunderstood my comment about the Sherman. I’d actually argue that – in light of the demands placed on its design, particularly by logistics – the M4 Sherman is a remarkable feat of successful design. I was merely noting that it is also a deeply compromised design and one with an (unearned, in my view) bad reputation with many enthusiasts in the public – although this seems to be turning around lately).