I've long wanted to do an analysis of how bomb accuracy has changed over the last 80 years or so, and how this impacts the cost of destroying a target from the air. The problem has always been that all of the data I need, from bomb accuracy to the cost of flying the planes, is scattered and sparse, and so I haven't really made much progress. But a recent comment from cassander inspired me to give it a try in Command: Modern Operations, which is basically a medium-level simulation package that is sold on Steam. I've used it for other experiments, and it could give at least a fairly reasonable number for how many bombs it takes from a given platform/delivery mechanism to destroy a generic target.

The basic setup I used for all of these tests was fairly simple. I set up a grid of 10 medium buildings (130' x 80') in CMO and then on the opposite side set up a nearby airbase with 12 planes of the type under test. All were given the same loadout (usually the heaviest one for the weapon in question) and set up to attack one at a time, using only one bomb at a time on a given target to prevent overkill from messing up my numbers. I would run the scenario until either all of the targets were destroyed or all of the planes had flown their sorties. Variables included the plane, the weapon, attack altitude and environmental conditions (day/night and weather).

For my first test, I ran a simple scenario: a modern fighter (Super Hornet) using dumb bombs, able to attack as low as it liked, with no weather conditions or other problems. The results were pretty straightforward:

So at this point, it's probably worth talking a bit about methodology. I'm going to count as a hit any bomb which does damage to the target, which can include both direct hits (16 of the 27 here, and, yes, many buildings survived direct hits) and bombs that don't hit directly but still do damage. Average miss counts the distance as 0 for direct hits, which is obviously somewhat optimistic (the target does have dimensions, so add maybe 25-30' to get actual CEP). For the next run, let's use the same loadout, but raise the altitude to 12,000', the sort of altitude you'd use if you wanted to avoid being shot at with MANPADS and guys with rifles.

Obviously, performance this time was significantly worse, with a lot of the bombs falling so far wide that they did no damage, although there were also 12 direct hits on the 10 buildings, which strongly suggests that the direct hits do the vast majority of the damage, an impression confirmed by later tests. That said, this one took long enough that several of the buildings were only damaged by the bombs and ultimately destroyed by fire. But the obvious next question is how this would work with bigger bombs, so I replaced the Mk 82s (500 lb) with Mk 83s (1000 lb) and ran the scenario again.

We see slightly better performance here, mostly due to the greater lethal radius of the bombs. In terms of total tonnage, it took slightly more Mk 83s, but fewer sorties because there were more bombs per plane. But it's also worth going up the final step and seeing what happens if we use 2000 lb Mk 84s.

This was the clear winner in terms of number of bombs required, although relative to the Mk 83, 6 sorties were required rather than 5 because the plane could only carry half of the bomb load. But with that baseline out of the way, I think I'm going to go with the Mk 83 for further tests with factors that could affect unguided bombs. First, I'll get a low-altitude baseline for comparison in various conditions:

It's worth noting that the low-level attack with Mk 83s required only about half the bombs that the Mk 82 version did, largely because the bombs were far more likely to destroy the building in a single hit. This definitely confirms the decision to use the Mk 83 as my standard test bomb when possible. Next, let's see what effect night has on the attack.

This test showed very slightly worse performance in terms of miss distance than the low-level day attack (hit percentage was higher, but the only "miss" in the day test was a bomb that malfunctioned). But it's not really that surprising that a fully kitted-out Super Hornet, with ATFLIR and ASG-34 IRST can deliver weapons nearly as effectively in the dark. Let's see how well that holds up to going to medium altitude.

The medium altitude results are quite similar to the daytime ones in terms of average miss distance and total bombs required. Hit percentage was substantially higher, although I think this is probably not the best metric to evaluate these tests by. It counts any bomb which does any damage, so it's easy enough for a lot of bombs landing 250'+ out, which really aren't doing very much to the building, to count as hits.

But now that we have a modern baseline, it's time to start looking back. I'm going to start with one of the earliest multirole fighters in this database,¹ the F-4J Phantom II, largely because it can carry the same Mk 83 bombs that I've been using here. We'll start at low altitude.

Here, we see a significant falloff in ability to do damage. Most of the bombs are still getting close enough to do damage, but it's gone from 14 to 26 to wipe out all the buildings. I'm going to try taking this to altitude next, although there's an obvious problem waiting. The Phantom's bombload is only 3 bombs, and it took 38 for the Super Hornets to destroy all the buildings from medium altitude. I'm going to set each of the Phantoms up to fly twice, to ensure a reasonable number of bombs get used.

This was obviously a massively different result than the Hornets from medium altitude, and a good indication of why the arrival of PGMs was so revolutionary. At the same time, the Phantom was not exactly known for being one of the best bombing platforms of the day, so let's try a different plane, the 1975 version of the A-6 Intruder, again attacking from medium altitude.²

This was an interesting comparison to the Phantom. The average performance was significantly better, with a lot fewer genuine flyers landing 1000'+ from the target, but it wasn't all that much better at actually landing the sort of hits that counted. Yes, it got all buildings in 74 bombs instead of 8/10 in 72, but most of the "hits" were 200'+ away and didn't do all that much damage.

I ran a night test with the Phantoms, and the results were extremely similar to the day test, at least until I tried to send out the second wave and it wouldn't launch, because that bombing mission was day-only. I'm not sure how I got the first flight off, or how the game models night in general, but I think this post has run its course. I'll pick up the subject later.

Also, on an unrelated note, CMO has just rolled out multiplayer for the standard game, so if anyone is interested in contributing to future posts like this by letting me put humans on multiple sides, let me know. To be clear, this is less "let's see who is better" and more research like in this post. But I'm curious to see what I can do in cases where I'm less limited by my ability to script things.

It's time once again for our regular Open Thread. Talk about whatever you want, so long as it isn't culture war.

Overhauls are Information, Communication and Naval Warfare Part 1, Falklands Part 5, The Battleship of the Future?, Wedding Decorations, A Brief Overview of the United States Fleet, Naval Radar - More Advanced Stuff, Speed and Range in Battleships, and for 2025, SCUBA Parts one and two, The Tanker War Part 2 and Exotic Hulls Part 1.

I've been watching through the documentary series The World at War lately, and figured it was worth talking about here. For those who don't know, it was aired in the early 70s, and is generally acclaimed as one of the greatest documentary series ever. I'm not much of one for documentaries in areas I'm familiar with, because they're frequently not particularly efficient and I often find myself frustrated by the editorial decisions made, but The World at War mostly manages to avoid these problems, and illustrates a conscious approach to doing history for the public that I really like.

The most obvious problem that any series like this is going to run into is simply how to divide up the war, because even with 26 episodes, a lot is going to be left out. TWAW handled this particularly well, abandoning any real pretense that it was going to be comprehensive and instead making each episode a self-contained story about a specific aspect of the war. This could be a battle or a campaign, the home-front experience of some nation or it could be something narrower like the Holocaust or the occupation of Holland. Particularly groundbreaking at the time was a significant focus on Russian experience during the war, and those portions were still some of the most interesting to me, as it's not an area I've studied extensively. But more importantly, each story generally does a really good job of balancing the human stories with the broad operational story of the war. Often history focuses either on "what happened and why?" or on "what was it like to be there?", and TWAW manages to balance both rather well. Read more...

Probably the most obscure corner of carrier aviation is COD, Carrier Onboard Delivery. This is exactly what it sounds like, the practice of delivering high-priority cargo, mail and personnel from bases ashore to aircraft carriers. The role originated in the immediate postwar years, and was first carried out by TBM Avengers modified to carry six passengers or cargo in the former bomb bay. But it was soon clear that the limited cargo weight and volume would be a problem for air-delivery of important cargoes like jet engines and nuclear weapons.¹

A C-1 Trader

The Navy ultimately chose to procure the C-1 Trader, a variant of their existing S-2 Tracker ASW aircraft with an enlarged fuselage. Entering service in 1956, the Trader would go on to serve for three decades in the USN, ultimately becoming the last operational piston-engined aircraft to fly from American carriers. But it was slow and limited in range, and, more importantly, it was soon unable to carry the largest jet engines in use by the fleet. The Navy again turned to Grumman to adapt an existing design with a new fuselage, turning the E-2 Hawkeye into the C-2 Greyhound. Ultimately, it would serve for almost 60 years until the growth of jet engines, in particular the F135 for the F-35C, caused the Navy to procure a new COD airplane capable of carrying it. The winner in this case was the CMV-22,² based on the V-22 Osprey beloved of the Marines and loathed by budget analysts. Read more...

In mid-October 1944, the American carriers under Admiral Halsey were operating in the waters between Taiwan (then known as Formosa) and the Philippines, to destroy Japanese power in the area before the US invasion of Leyte. Unfortunately, on October 13th, the heavy cruiser Canberra was torpedoed by Japanese aircraft, flooding both engine rooms. Normal practice would have been to take the crew off and abandon her, but Admiral Halsey decided to tow her clear by cruiser Wichita instead. The next day, light cruiser Houston was also torpedoed, losing not only her engines but also all of her boilers, which meant there was only emergency power available throughout the ship. She was in considerably worse shape than Canberra, with serious concerns that she would break up early on, leading most of the crew to abandon ship before the decision was made to try to tow her clear as well.

The path of CripDiv 1³

On the morning of October 15th, a group, dubbed "CripDiv 1", was formed to protect the two crippled cruisers, with three light cruisers and eight destroyers to provide close cover. Light carriers Cabot and Cowpens, with a separate group of escorts, would provide air cover. Houston, towed by heavy cruiser Boston, spotted the group shortly after Wichita passed the tow to tug Munsee, and finally reached her station around noon. Meanwhile, Radio Tokyo was putting out increasingly outlandish claims about the damage inflicted on the Americans, prompting parties in the streets. Halsey's staff wondered about how much was deliberate propaganda and how much the Japanese genuinely believed. If they were taking their more outrageous claims (half a million tons of shipping sunk, 53 ships including 16 carriers on the bottom) seriously, then it was plausible that they'd send surface forces out to mop up. One carrier group was sent to hit airfields around Manila on the 15th and 16th, while two others were pulled out of range of Japanese search planes in the hopes of luring them out. Only one was left in position to protect CripDiv 1, an understandably unpopular move among the men of the group. One of the captains of the escorting light cruisers commented "Now I know how a worm on a fishhook must feel" and the name "BaitDiv1" began to circulate. Read more...

After the Naval Gazing meetup in Dayton, my parents and I headed for Montreal,⁴ which meant a road trip, mostly across upstate New York. I've already talked about one of the museums we visited along the way, Old Fort Niagara, but there were several others, none of which deserve a full review of their own.

The canal boat at Port Byron

The first was only sort of naval-related, but fits well with my general interests. The Old Erie Canal Heritage Park at Port Byron is just west of Syracuse and right off I-90, and is dedicated to the history of, unsurprisingly, the Erie Canal, originally opened in 1825. This was one of the great wonders of the era, dramatically easing transportation between the Hudson River Valley and the interior of the continent, and this fairly small park has the remains of one of the locks, as well as an old tavern, where crews would get a beer while their boat was locked through, and a visitor center with some exhibits on the construction and history of the Canal. The tavern has recently been restored, and is a fairly typical slice-of-life history museum, while the museum has recently acquired a replica canal boat, which they are in the process of setting up to open to the public. On the whole, it's a pretty nice way to take a break if you happen to be cruising that part of I-90, although it's probably not worth going particularly far out of your way for. Read more...

It's time once again for our regular Open Thread. Talk about whatever you want, so long as it isn't culture war.

Something of interest to lots of you is Naval Estimates, a new game that is best described as Rule the Waves, but with a much more detailed engineering simulator built in. Or at least that's the plan. Right now, it's just the weapon and ship design simulator that's available, and it's just set up for the British, c.1905. That said, it's remarkably good for that. I did some checking against a few books, and it does as good a job as you can ask modeling pretty much everything. I plan to do a longer writeup when the battle system is available, but it's still an impressive result for a one-man operation, and Elouda (the creator) is hopefully just getting started.

Overhauls are my review of Batfish, Falklands Part 4*, Museum Ships - United States, Signalling Parts one, two and four, NWAS - ASW Part 1, Zumwalt Parts one and two and for 2025, my review of the Oakland Air Museum, Military Spaceflight Parts eleven and twelve and Allied Military Aircraft Part 1.

When Iraq's 1980 invasion of Iran ended in a bloody stalemate, it was natural for both sides to turn to other ways of bringing pressure on their enemies. These ranged from firing missiles at the other guy's cities to attacking the oil exports that fueled their economies. Iraq had started to route its exports through Kuwait and Saudi Arabia, and as Iran expanded its attacks to include neutral shipping, the US grew increasingly concerned, both about the flow of oil from the Arabian Gulf,⁵ and potential Soviet influence in that vital region. As a result, the Administration agreed in March 1987 to reflag 11 Kuwaiti tankers as American vessels, allowing the USN to escort them through the Gulf.

Stark next to flagship La Salle in Bahrain

Two months later, even before the escort operations began, the frigate Stark was accidentally attacked by the Iraqis in a tragic case of mistaken identity. Previously, the increasing US involvement in the Gulf had been a matter of little concern, but 37 dead sailors was enough to get the country's attention. Opponents of the administration charged that it was involving the US in an open-ended war against Iran without thinking through what would be needed to win or getting the approval of Congress. Many compared it to the Administration's bungled Lebanon strategy of a few years earlier. A particular concern was that the Iranians usually attacked tankers in retaliation for Iraqi strikes, so the vulnerability of American ships depended heavily on what Saddam did, and he wasn't even vaguely an ally. But he was smart enough to pause attacks on Iranian shipping as the escort operation began. The Iranians were obviously upset, but their actions rarely matched their rhetoric, so the reflagging went ahead and the first convoy was scheduled for late July 1987. Read more...

One of the first tasks of a new British prime minister is writing four letters. These "Letters of Last Resort", each identically worded and written by hand after a briefing on the destructive power of the Trident missile, are sealed and delivered to the four British Vanguard class submarines. They contain instructions on what to do in the event of nuclear war, and will only be opened if the submarine's crew determines that Britain has suffered an attack and no orders are forthcoming. If this doesn't happen, they will be destroyed unopened when the next Prime Minister takes office.

One of the chief problems of any nuclear deterrent is that both the weapons themselves and the command-and-control infrastructure will be prime targets for an enemy's nuclear weapons. The first problem is relatively easy to deal with, and most countries solve it by sending some of their nukes to sea aboard submarines, which are by nature difficult to find. The British, in fact, like this approach so much that they chose it for their entire nuclear arsenal. But nuclear weapons aboard a submarine, while fairly safe, are also of little use if orders to fire them can't be given. The US solves this with a massive command-and-control infrastructure, including not one, not two but three different converted airliners. But there are two problems with this kind of system from a British perspective. First, it's really expensive, and the British can't afford US defense budgets. Second, Britain is considerably closer to potential threats, who should remain nameless but who I will assign the randomly-chosen name "Russia" to, than the US is. This gives even less time to get a message off to any nuclear forces, to say nothing of the problems of communicating with SSBNs. Read more...

On October 14th, 1944, the three carrier groups of TF 38 were conducting strikes on Formosa. The operation had been planned to provide distant cover for the approaching landings at Leyte, and had been scheduled to wrap up the previous day. However, heavy cruiser Canberra had been torpedoed during the last set of strikes, and it was decided to tow her home instead of scuttling her, which required an extension. Three groups would again spend the morning pounding the airfields of Formosa, while the fourth was dispatched against Japanese air bases in northern Luzon. The strikes themselves encountered little opposition, but also failed to shut down the air bases, and all of the US carriers groups were trailed by snoopers throughout the day. TG 38.2 and TG 38.3 began to withdraw in the afternoon, leaving behind TG 38.1, the Task Group Canberra had originally been assigned to, to cover the withdrawal of the crippled cruiser.

Houston underway earlier in 1944

As such, it was TG 38.1 that caught the bulk of the Japanese dusk attack, again in the form of torpedo bombers. 11 to 16 Frans appeared, and while most were shot down or driven off by AA fire, a few got through to drop their torpedoes. This time, their target was light cruiser Houston, transferred from TG 38.2 the previous day to take over Canberra's station. She found herself facing three torpedoes in the water, two to port and one to starboard. Only the one from starboard got through, but it hit in the worst possible spot. The ship had been turning to evade, rolling heavily to port, so the torpedo detonated against the ship's bottom, halfway between the centerline and the bilge keel, and directly under the turbines for shaft 1 in the forward engine room. The space flooded almost instantly, and the explosion damaged the bulkheads forward and aft, flooding both boiler rooms over the next few minutes. Read more...