Our recent look at missile combat in Aurora has rounded out our examination of the basics of warship design, so it's time to turn our attention to the various systems that I ignored for the sake of simplicity. Some of these are important for individual warships, while others are of more concern to the fleet as a whole.

One of these primarily fleet considerations is passive sensors, which come in two types: thermal and EM. Thermal sensors detect the heat of a ship's drives, while EM sensors primarily pick up the radiation from an enemy's active sensors and shields. Colonies and populations also have EM and thermal signatures, and a major colony can be detected at long range. Passives are far more important for the fleet as a whole than they are for individual ships, and I usually build dedicated scouts which not only operate with the fleet but also gather strategic information on potential enemies. It's also worth fitting any vessel that is likely to operate on its own (such as survey ships) with smaller passive sensors to make sure they aren't completely blindsided by the appearance of hostile aliens. At the very least, you'll know who did it and be able to recognize them if they show up it again. Read more...

In 1815, the series of wars that had lasted more than two decades finally drew to an end. The resulting "Pax Britannica" would last almost a century, although it was not entirely peaceful, and coastal defenses would often find themselves on the front lines. Naval power focused on projecting influence ashore instead of on fleet battles,¹ both in the wider world as a result of European colonial expansion, and in Europe as a result of changes in strategy driven by new technology. Some countries also focused on coastal defenses as a cheaper alternative to fleet power, most notably the US.

Fort Knox, Maine, a third-system fort²

In 1816, Congress authorized a third fortification program, which would prove a marked departure from the First and Second Systems. The Third System was built in the absence of any specific threat, intended instead to provide long-term protection by a well-planned series of fortifications. In keeping with this long-term approach, a board was appointed to designate the locations of fortifications, prioritize them, and supervise planning and construction. As a result, the Third System would be much more coherent than the previous fortification efforts, and many of the results remain standing today. Read more...

As we make our way through Aurora, we've finally reached the point where we can talk about offensive missile warfare. Because offensive missiles require an understanding of how to defend against missiles, I'm going to be relying heavily on the previous parts about defending against missiles with beams and anti-missiles.

The first step to take when using missiles is to decide on a standard size for your offensive missiles. It's possible to run multiple sizes on different types of ships, but I'd recommend against it. That way lies micromanagement madness. On the whole, I'd recommend sticking to missile sizes between 4 and 6. Any missile of size 6 or smaller is picked up by active sensors and fire control at the same point, while larger missiles are picked up further out, so that as a cap maximizes your ability to penetrate defenses. Going smaller means more missiles per salvo, and a shorter interval between salvoes, but less-capable individual missiles. Anything smaller than Size 4 is likely to pay too high a price in capability. Read more...

The Tomahawk missile began life as a strategic weapon, intended to bring nuclear firepower to the Navy's surface ships and submarines. The Navy quickly adapted it as a long-range anti-ship weapon, although the bulk of Tomahawk's impact was made by the second generation of Tomahawks, the Tomahawk Land Attack Missile (TLAM)-C and TLAM-D, equipped with a 1,000 lb conventional warhead and a submunition dispenser respectively. Tomahawk's combat debut against Iraq in 1991 was a triumph, and soon the weapon became a favored instrument of US politicians, thanks to its accuracy and lack of a pilot at risk of being shot down.

An RN Tomahawk in flight

Even as the dust settled from the first Tomahawk strikes in Iraq, a new version, known as Block III, was being tested. The single most important difference from the Block IIs used in Desert Storm was the addition of a high-precision GPS receiver. This removed the various constraints of TERCOM and DSMAC, allowing the missile to be used on targets that hadn't been mapped to within an inch of their lives, and giving targeters more flexibility with routes.³ TERCOM and DSMAC remained an option, though, and improvements were made to the later system. Also improved was the warhead on the TLAM-C, with advancing explosives technology allowing it to shrink to 700 lbs, giving space for more fuel and increasing range to around 870 nm (1000 regular miles). Rounding out the package is an improved engine with about 20% more thrust. Besides newly-built Block IIIs, many Block IIs and TASMs were converted to the configuration. Block III also saw the Royal Navy join the Tomahawk program, buying a number of UGM-109s for its submarine force. Read more...

A fair bit of this has been superseded by the changes made in 2.2, which I've written up here and here. If you're new, read this first, then look at those for the current version. Quite a bit has changed here, and I'm not going to do a full rewrite.

Welcome back to my Aurora Tutorial. We're currently discussing combat, specifically warship design. Last time, I covered missile defense with beam weapons, but now it's time to shift to the system I usually base my defenses around: anti-missile missiles (AMMs). AMMs have benefits and drawbacks relative to beam defenses. On one hand, I've generally found them to perform better than beams and to be more effective, particularly in the face of a massed attack. They're also much easier to upgrade, as you can just swap in a new missile with improved performance. On the other hand, AMMs can get expensive, and the ships firing them have limited ammo capacity. If they run through their magazines before the enemy does, you're dead.

So what is an AMM? Like beam defense, AMM defense is a numbers game. You need the smallest feasible missile, fired at the highest possible rate, so the obvious result is a size-1 missile⁴ with a strength 1 warhead,⁵ optimized for the highest hit probability possible and with sufficient range to match the sensor/fire control combination you have planned. As such, you should probably design the electronics first. Missile fire controls are built in the same tab as active sensors, and have the same range characteristics. On average, a typical MFC has about the same range as a search sensor 3 times its size. I usually try for a size 3-4 sensor, and an MFC that either matches it in range or is a little bit better. I do this because I expect later missile defense ships to have better sensors, and a slightly oversized MFC lets the older ship take advantage of the extra range. So going back to the AMMs, a missile's hit probability is equal to (missile speed*maneuverability*0.1)/target speed. Maneuverability is based on how much space you've put into agility⁶ so you need to find a balance between spending space on the engine and spending it on agility. Read more...

Today marks the 104th anniversary of the Battle of Jutland, the climactic naval clash of the First World War. This is a topic I've discussed at some length already, so it's worth turning our attention to the background the battle was fought against, the British blockade of Germany.

The headquarters of the Northern Patrol, who enforced the blockade

While most think of globalization as an inherently modern phenomenon, it was almost as prevalent in the first decade of the 20th century as it was in the first decade of the 21st. Britain and Germany were two of the leading players in the new global economy, deeply tied into international trade. Britain got over half of its food from overseas, while Germany imported a quarter, to say nothing of the essentials necessary to sustain an industrial economy. Each rightly deduced that the other was vulnerable to attacks on its commerce, although they set about it in very different ways. Germany, knowing that it was outmatched at sea, planned a classic guerre de course based on commerce raiding by converted merchant ships and cruisers. This ultimately failed in the face of British innovations in Command and Control, forcing them to switch to submarines for their attacks on British commerce. Read more...

It's time once again for the Naval Gazing open thread. Talk about whatever you want, even if it's not military/naval.

Amazon Prime seems to be the service for naval/military movies. (I promise I am not getting paid by Jeff Bezos.) Recent ones I've watched include Run Silent, Run Deep, the Final Countdown and Strategic Air Command. The first is based on the novel of the same name, and is decent, if not quite as good. The Final Countdown is conceptually extremely silly, but has lots of very cool 1980-era carrier ops footage. The only thing that really annoyed me was in the scene where they're launching the strike against the Japanese fleet. Why did you fly off three Prowlers? They won't get their first air-search radar for another 6 months! And Strategic Air Command is extremely mediocre of plot, but has a ton of extremely nice aerial and ground footage of B-36s and B-47s.

2018 overhauls are There Seems to be Something Wrong with Our Bloody Ships Today, Millennium Challenge 2002, Auxiliaries Part 1, Falklands Part 2, my review of The New Maginot Line and the first three parts of my Jutland series. 2019 overhauls are the pictures of my early visits to museum ships, the Falklands glossary, the Montana class, So You Want to Build a Modern Navy - Aviation Part 4, Battleship Aviation Part 2 and Shells at Jutland.

A fair bit of this has been superseded by the changes made in 2.2, which I've written up here and here. If you're new, read this first, then look at those for the current version.

Last time in my Aurora tutorial series, we looked at the basics of beam weapons and warship design. But beams are not the only threat out there, and the hardest thing for new players to get is usually missile defense. I once ran a multi-player game where several of my friends (unfamiliar with Aurora) were each given a race and turned loose. I also ran my own power, which I attempted to nerf to keep things relatively even, and use as a wildcard. As it turned out, I significantly underestimated how much nerfing I needed. When one of them tried to attack me, I managed to destroy his fleet with essentially zero difficulty despite a significant technological disadvantage. I knew missile combat and he didn't, so his defenses were ineffective.⁷

Despite this, building an effective missile defense isn't particularly difficult. It just needs to be taken seriously, because the AI opponents can throw a lot of missiles. For beam defenses, this basically means that you need to optimize for the maximum number of hits (of any damage, because missiles are killed by 1 damage) at point-blank range against fast-moving targets. The math on all of this is made easier by the fact that pretty much everything scales linearly. In particular, if a target is moving faster than the attack's tracking speed,⁸ the chance to hit is equal to the chance for that range times (tracking speed/target speed). At any given tech level, it's easy to build effective missiles that are faster than 4x racial tracking tech,⁹ so it's best to just treat the turreted weapons as 4X more likely to hit for analytical purposes. There's a box on the right side of the ship-design window that lets you set the speed and range the FC to-hit values will display for. Read more...

The Tomahawk missile has been one of the most influential developments in naval warfare over the past half-century. While it began as a nuclear missile, and was soon developed for anti-ship roles, the most famous version of the Tomahawk, and the only one to remain in inventory today, is the conventional TLAM (Tomahawk Land Attack Missile). The TLAM gives conventional surface ships and submarines the sort of inland reach and firepower that was previously only available to carriers.

Iowa launching a Tomahawk

Developing the TLAM wasn't as simple as mating the guidance system from the nuclear version with the warhead of the anti-ship Tomahawk. While the TERCOM¹⁰ guidance system was perfectly adequate for a missile with a nuclear warhead, it couldn't get the missile close enough for the 1,000 lb warhead to be effective. Another, similar technique known as DSMAC (Digital Scene Matching Area Correlator) was used to bridge the gap. This was essentially a camera on the missile that would provide an image to be compared to a stored file of processed satellite imagery. By matching the two, the missile could figure out where it was with even greater precision, and the technique is fairly robust against changes within the image. This is possible because the missile isn't looking for the target directly, but is instead using the data to update its estimated position, and then flying to the pre-planned target coordinates. To make sure that DSMAC could still work at night, the missile was fitted with a strobe light. Read more...

We've come through a lot of Aurora's economics/colonization gameplay, and it's finally time to talk about the really cool bit: warfare. This is an extremely complex part of the game, and while there are multiple feasible playstyles, it's also an area where it's easy to get things wrong and end up with a useless fleet. So before we start actually playing with the wonderful shipbuilding system, let's take a look at the broad overview of combat, which we will then flow down into how to build not just ships, but an integrated fleet.¹¹

There are two types of weapons in Aurora: beam weapons and missiles. Beam weapons come in a number of different varieties. All have essentially infinite ammo (with a few restrictions) and are only useful at short ranges (~100kkm for beams, ~50mkm for missiles), meaning your fleet needs to be able to close with the enemy (this usually means higher speed than a missile fleet) and survive any missiles they can throw your way. Missiles have to be researched, built and transported separately, but offer you the opportunity to avoid beam combat. On the whole, I tend to prefer missiles, although this is as much an aesthetic as a practical choice, and many other options can be made to work. Read more...