This week’s post will be a bit shorter, as the holidays are now upon us and the year is winding down (but don’t worry – I have a humdinger of a series planned for January – no, not that one; one you did not expect). This week is going to serve as a bit of an addendum to Where Does My Main Battery Go and a bit more silly sci-fi fun to round out the year. Specifically, I want to expand a bit on this statement:
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’).
I wanted to expand on this idea and trace it historically.
What I often see in sci-fi settings are space warships that look like this:
Or even the venerable Imperial Star Destroyer (in this case, an Imperial I, because yes, I am that kind of nerd – you can tell from the communications tower):
What strikes me as off about these designs are their silhouettes – or rather, what they imply, which is that they have been designed around a shape rather than around a function. For the Star Destroyer, at least, I can see parts of the design that have been forced to make way for the main reactor, which bulges out of the bottom of the ship (but my heavens, the decision was made to deform the primary armor around the reactor, rather than simply designing the ship from the ground-up to put such an important thing entirely internal to the spaceframe?). But for what is essentially a gunship, what is so striking about the Star Destroyer is how muted the main battery is to the overall design – I suspect most movie-goers don’t even notice the turrets set on either side of the central island (which is also, as an aside, a terrible spot for them).
Instead, the main armament – and even, to a degree, even the propulsion – appears to be an afterthought. Some series do this more than others – Star Trek ships generally have very prominent engines (in those classic nacelles), but with such understated main weapons – even on the more militarily focused Constitution and Sovereign classes – so much so that the SFX teams routinely forgot what is where and had the wrong weapon shoot out of the wrong place (Kirk, in particular, seems fond in the original series of firing phasers out of his torpedo bays).
(I don’t want to get too out of the way making fun of Sci-fi ship designs, but can I just note that the basic layout of Federation starships – with engines connected to the main ship by long, fragile pylons, makes no sense. I mean, I understand from a production standpoint that originally the idea was that every ship would have two warp nacelles and they’d always have to have line-of-sight on each other to work (thus the moving nacelles on Voyager and Ferengi ships), but they seem eventually to have ditched that in later designs, which then makes what is supposed to be centuries of Federation ship design look really, really foolish if that line-of-sight thing wasn’t strictly necessary.)
What almost all of these ships seem to have in common is that they look like actually began with the shape of the ship and then back-filled how the key components of the ship might fit in with that shape. And that’s probably because that’s exactly how they were made – with artists and modelers working up from a basic idea of the overall shape and visual style of the ship and adding details. Often – as for instance with designers discussing Star Wars starfighters here (note that they discuss the new movie in the last few minutes) – they began by adopting shapes from existing machines.
The problem with this is that you get a ship where the primary purpose of the craft is literally an afterthought in its design – a few tiny ‘guns’ glued on to the side of the model after it is by and large done. And so what you don’t see – compared to any kind of historical warship – are the ways that the demands of the two most dominant design features, propulsion and armament define the shape and silhouette of a design. Indeed, in some ships, the design seems to literally contort around these features – as well it should, as they are the reason for the ship!
Early Purpose Built Warships
To see what I mean, lets talk about the design of naval warships. Now, in a way, the design of historical warships is, if anything more restrictive than the design of most space warships, which tend (in their respective fictions) to be built in space and never operate in atmosphere. Ships that ply the seas rather than the stars are constrained by the shapes they must have to sail effectively; starships have no such limitations.
I’ll cut to the chase: the silhouettes of historical warships are always dominated by two key factors: propulsion and armament. In nearly all cases, everything not directly linked to one of those two facets of performance is relegated to a secondary status (we should make exception, especially in the modern era for armor, but modern warship armor has more often had to conform to a shape dictated by the other two factors, rather than the other way around – that said, the impact of armor on weight was a huge influence in warship design, and a considerable, but more subtle and harder to spot – but very important – influence on warship shape).
This makes a certain degree of sense: the primary role of any purpose-built warship (aside: I’m going to avoid multi-purpose craft – ships that can serve both military and civilian roles – here, in both my sci-fi and real world examples) is to deliver a primary armament of some sort to a battlespace. The subordination of every other function of the ship to these main purposes plays itself out visually in the design. Let’s start with an old example: possibly the oldest purpose-built warship in the world, the Mediterranean trireme:
What I’m going to do with each of these images is put red marks around the primary armament of the ship in question and blue marks around the propulsion systems. In the event, the trireme is an awkward first example: the oars serve both as part of the propulsion, but also part of the armament, as the trireme’s main weapon was speed. While later Mediterranean oared warships may have been more focused on boarding (this is a hotly contested topic, I recommend W. Murray, Age of the Titans (2012) to get a sense of the debate and the design considerations it spawned), the trireme was definitely a ramming oriented ship. The perfect engagement was one where it got in, got the hit, and then backwatered back away again.
Consequently, triremes were built for speed, because speed was offensive power. Everything was sacrificed for this: there is functionally no cargo room, literally no crew quarters (the rowers slept on their benches) and the ship’s structure is built light and thin (with costs to both survivability and seaworthiness). Occasionally a sci-fi show will joke that a given ship is “little more than guns with an engine strapped on” but the trireme is almost literally this thing – little more than a ram with a (human powered) engine installed in the back.
Centuries of evolution in the design did not change the basic balance of speed and armament:
Moving into the age of sail, we can see a similar dominance in ships of the line:
Now, the ships of the line are a bit of an odd case, because they descend from, and thus share design characteristics with, the multi-purpose sailing ships of the 16th and 17th centuries. Nevertheless, the design demands of being a specialist warship have taken their toll: the demand for more guns meant stacking additional gun-decks vertically, which in turn gives the ship a deep draft (which you cannot see, because it’s below the waterline; and yes, yes, this is a British ship, so I suppose it has a deep draught). That in turn has demanded a broader beam (that is, the ship is wider) to maintain a stable platform – Victory, with three decks of guns (plus lighter guns on the quarterdeck) is nearly 16m wide, while a classic 74-gun third-rate ship of the line might be only 14m wide, and a single-gun-deck ship like a light frigate might need only to be 10-12m wide.
Alright, I hear you say, but what about a more modern ship? Something with an engine? One of the (more or less) constants of pre-dreadnought and dreadnought design was that, in terms of displacement (essentially weight), around two-third of any given battleship consisted of the main propulsion, the primary armaments, and the armor. Everything else – everything else: crew quarters, crew amenities (food, post, hygiene, recreation, social spaces), command spaces, storage spaces, damage control equipment, machining tools for repairs, all of it – had to be squeezed into the remaining third or so.
Meanwhile, the relatively inflexible demands of the shape of the main battery and primary propulsion (along with the demand for elevated command spaces to allow for effective navigation and spotting) mean that all of those other things had to be crammed into whatever space the ship’s hull made available. As an aside: this design philosophy is abundantly clear if you’ve ever been on a museum ship that lets you get around even a little bit – bunk spaces and mess halls and the like are crammed into whatever space is available, sometimes contorted around other, more important ship functions. For instance, the world’s sole surviving pre-dreadnought, IJN Mikasa:
Now, you may say – “wait, but you’ve designated the secondary guns as part of the main armament” – but remember, this is a pre-dreadnought, so the secondaries are still conceptually part of the main armament, which is why they’re allowed to dictate so much of the ships central mass, rather than being confined to casemates or upper-works wherever they will fit (a more common pattern in later dreadnoughts, until WWII when the placement of secondaries, now anti-air batteries, begin to matter a lot again) – instead, the housing for the casemates of the secondary battery is a core part of the design and takes up a lot of the space above the waterline.
The propulsion system of a ship like this dominates the space of the ship’s lower decks. On Mikasa, directly beneath the smoke-stacks were 25 coal-fueled boilers, which fed power to a pair of triple-expansion engines (a compound steam engine which passes the steam through multiple cylinders to extract more power) set aft of the boilers, which in turn drive the shaft out to the propellers. The space the entire assembly demands is actually visible in the placement of the stacks – no doubt naval designers would have loved to place the smoke-stacks somewhere, anywhere where they wouldn’t frequently cloud the aft spotting tower with smoke, but the demands of powerful engines capable of moving such a heavy ship at respectable speeds forced compromise.
I think modern warships – by modern here, I really mean post-1880 or so – conceal some of the degree to which propulsion and main armament dominate the ship’s design (and thus its appearance) because so much is hidden beneath the decks. Note, for instance that the big-gun turrets are not the only part of that gun system – the entire gun assembly is actually five decks tall, plus the turret, beginning with magazines and ammunition storage at the bottom, and a lift for shells to be brought up to the guns. The motor that turns the turret is roughly at the waterline (on the platform deck) and the systems to elevate and train the guns are themselves nearly two decks tall. That assembly is protected – above and below the main deck by an armored shell called a barbette. A large part of the reason this entire setup is stacked vertically is so that the magazines – which take up quite a bit of space – can be placed as low in the hull as possible, since a hit to a magazine would almost certainly doom the ship. In short, the barrel of the gun and the turret that you see poking out of the top are just the tip of the iceberg of the total gun assembly.
And remember, this is a pre-dreadnought, oriented around a mixed battery of guns. What about a modern ‘super-dreadnought’ all-big gun battleship? Now, I’m sure you’re all expecting Yamato and Musashi‘s massive 18.1in guns, but I don’t have a good internal layout plan for the Yamato, so I’m going to go with an USN Iowa-Class ship, the USS Missouri (BB-63), both because I can find a full deck plan, but it’s also a design I’m more familiar with. Same deal as before:
The turret assembly for each of the (technically-not-triple, they can elevate independently) triple-16in turrets is even larger than Mikasa and runs all the way to the keel and fills nearly all of the horizontal space on every deck with the equipment for raising shells, elevating the guns, turning the turrets, magazines and so on. You can get a pretty good sense of what all of the stations in the turret are doing from this 1955 training video on the operation of the guns.
I want to contrast that with the scale of a Star Destroyer’s main armament – you will need to excuse the poor picture, I took it from my copy of Star Wars: Incredible Cross-Sections (I told you, I am that kind of nerd – I’ve had this book, along with the Essential Guides, since I was in high school, much of it even back before the Dark Times, before the Prequels), the book is quite large and scanner-unfriendly, so I had to use a camera:
By my count, the entire assembly – fire control, power cells, the turret itself, everything but the reactor powering the damn thing – comprises about 8 decks. To give a sense of the comparative size of these two ‘battleships’ – the Mikasa is 131.7m long and has a beam of 23.2m; a Star Destroyer is supposed to be 1,600m, and up to 600m wide. It is, conservatively, something like two thousand times larger than Mikasa (perhaps a thousand times the size of Missouri) in terms of total volume, yet the gun main gun assembly looks to be only a bit larger – and it includes fire control (which was not housed inside the turrets on historical battleships because that is a very silly place for it) – and it only has eight main turrets. The total volume – and one assumes mass – of the Star Destroyer devoted to its armaments – even if the main reactor is included – is shocking small.
It really makes me wonder what all of those other decks are for on a Star Destroyer. Oh, sure, you have the hanger spaces, but these are all in the thin end of the wedge and don’t even seem to fill that – what on earth is taking up all of the space in the massive island in the center-aft of the thing? Looking at various cross-sections and technical drawings, the answer appears to be ‘nothing.’
(As an aside before it comes up: ‘what about aircraft carriers?’ Well, the main armament of an aircraft carrier is its air-wing, which (in its full operation) takes up the entire flight deck, plus the entire hanger deck, both of which in modern carriers run the full length of the ship, plus armory spaces further down and repair and machinery. If anything, an aircraft carrier is more contorted by its main armament than any other modern type of warship.)
After the last post on sci-fi ship design, a number of folks asked me if there were any designs that struck me as having felt a bit more on-target. And there are some – a common design, particularly in video-games, are ships built around a single large spinal-mount railgun (e.g. Mass Effect, Halo), resulting in a design with a main reactor in the middle, plugged into an engine assembly behind it, a gun assembly in front of it, and the rest of the ship essentially wrapped around that core in whatever shape will fit. I also think that – though I am only now making my way through the series – a lot of the ships of The Expanse strike a good balance, for instance the Donnager-class:
The main armament is on the bow in two massive turrets and one assumes that the power, ammunition and battery stems for those huge railguns dominate that mid-ship-section, while the massive engine (and presumably reactor) dominate the ship’s aft (although it also has a lot of big internal empty storage space which I find a little unlikely for a ship that is still essentially a gun-delivery-system. Science-fiction loves big multi-multi-purpose ships with marines and fighters and guns and mid-sized craft, but in practice it is hard to see why those functions wouldn’t be split up between specialist craft (so that you are only lugging the capabilities you need, all the more important when fuel and available delta-v matter).
And that will be the last scheduled Collections post for 2019. There won’t be a normal Friday post next week because of the holidays (I will be taking some much needed rest, and by ‘rest’ I mean I will be attempting to catch up on my research). The week after that will also be an ‘off’ week (the first week of January plays host to both the largest professional conference for historians and the largest professional conference for classicists and archaeologists. Obnoxiously, always on the same days and never in the same place.) I may have a few one-offs here or there, but the regular posting schedule will resume on January 10th.
New things to come with the New Year!