I've previously showed pictures of Iowa's Main Battery Plot, and now it's time for the follow-up of the Secondary Battery Plot.

This space contains two Mk 1A computers along with their associated Stable Verticals, set up to control the 5" guns. This required dealing with targets that are both very fast and moving in 3D, a truly incredible achievement. Read more...

It's time for our regular open thread. Talk about whatever you want, so long as it isn't Culture War.

First, apologies for not doing a meetup in September. I've been busy, but we'll do one next Saturday (October 9th) at 1 PM Central.

Second, the blog's 4th anniversary is approaching, and I'm finding myself getting burned out. So I'm going to put it on hiatus during November, and maybe into December. I'll still do the regular OTs, but if there's to be other content, it's going to have to come from you guys. Email me at battleshipbean at gmail if you want to contribute a museum review, book review or other naval/military related thing.

2018 overhauls are Secondary Armament parts one, two and three, Battlecruisers Part 3 and my reviews of Mystic Seaport and Albacore. 2019 overhauls are Fouling, Naval Ranks - Warrant and Enlisted, my account of my first visit to Iowa, River Warfare - China Part 1, the McKinley Climatic Laboratory and HMS Warrior. 2020 overhauls are the Arleigh Burke class, Territorial and International Waters, Falklands Part 24 and my pictures of Iowa's aft living spaces.

It's finally time for our long-running photo tour of Iowa to reach my favorite space, the plotting rooms. The main and secondary battery computers are in separate, adjoining spaces, and can be visited on special tours. I'm usually too busy with certain activities (seen below) to take many pictures, so these were taken over half a dozen visits.

Despite this, I ended up with enough pictures to split this into separate posts for the main and secondary battery plots. This will cover the main battery plot. For a full explanation of how everything works, see here. Read more...

In only four years from the launch of the first Liberty Ship, Patrick Henry, 2,708 vessels of that type were launched. The vast majority were simple general cargo ships, boxes capable of carrying 10,000 tons of material across the oceans at 11 kts. These formed the backbone of the Allied merchant fleet that carried 203,522,000 tons of dry cargo from the United States overseas during the period between the attack on Pearl Harbor and the Japanese surrender. But break-bulk cargo was far from the only thing that needed to be moved overseas.

USS Porcupine, a Liberty Tanker

The second-largest category of cargo that needed to be moved was liquid in the form of petroleum products, a total of 64,730,000 tons during the war.¹ Tankers were a favorite target of the U-boats, and it took until February 1943 for construction to consistently outpace losses. The Maritime Commission preferred the fast T2 tanker, but in late 1942, necessity forced the conversion of Liberty Ships to tankers. To disguise them, they retained dummy cargo-handling gear, and often carried deck cargo such as vehicles. All of the plumbing for the tanker role was hidden underneath the deck, with bulkheads built into the cargo holds to form 18 tanks. Ultimately, 62 of these tankers were built at New Orleans and California Shipbuilding, and gave good service, although most were converted back to dry cargo duties postwar. 18 of these were taken over by the Navy as the Armadillo class, used to carry fuel to rear areas, mostly airbases in the Pacific. Read more...

One of the great battles of the Second World War was fought in the shipyards. Moving the products of American industry to where they were needed to support the war effort would take ships, and when the US entered the war, those were in short supply. The centerpiece of this effort was a new design of freighter, intended to be easy to build and operate, dubbed the Liberty Ship. Existing shipbuilding capacity was insufficient, and through several waves of expansion, US industry geared up to produce 24 million tons of shipping capacity throughout 1942-1943.² Ultimately, they would produce 2,708 Liberty Ships, in addition to about 3,000 other vessels built for the Maritime Commission, the agency charged with supply merchant ships for the war effort.

Day 2: Keel plates are welded on the slip at Bethlehem Steel's Fairfield yard

Building the vast fleet of Liberty Ships, by far the largest number of major seagoing vessels ever built to a single design, required a radically new approach to the problems of shipbuilding. Traditional methods relied on skilled labor and built high-quality vessels in small numbers. But the name of the game for the Liberties was multiple production, as builders raced to send ships down the ways as fast as possible, minimizing the time each had to remain on the slip before launch, as that was usually the bottleneck. From the first round³ of ships to the tenth in a given yard, average time on the ways fell by 80%. The overall victor in this contest was Oregon Shipbuilding, who managed to maintain a pace of 17 days per round in mid-1943. A few ships were built much faster as propaganda exercises, the record-holder being Robert E Peary at Richmond, launched 4 days, 15 hours and 29 minutes after her keel was laid, thanks to extensive prefabrication and massive use of resources. Three days later, she was completed and handed over to the Maritime Commission. But while this was a one-off, the average Liberty delivered in the last third of 1943 had had her keel laid only 41-42 days previously. Read more...

In late 1941, the US was gearing up for war. The nation's vast industrial might, idled by the Great Depression, was harnessed to produce material both for Britain and for America's own defense. But the biggest problem would be getting the products of the Arsenal of Democracy overseas, as the fighting fronts were far from American shores, and to do that, merchant ships were required. Efforts to rebuild the nation's merchant marine had been ongoing since 1936, but were not far enough along to bridge the gap, particularly in the face of the depredations of German U-boats. The answer was an emergency shipbuilding program of 9 yards to produce vast numbers of vessels capable of carrying 10,000 tons of cargo at reasonable speed. The first was launched on September 27th, 1941, and the type was dubbed the Liberty Ship.

But even the prewar program, scheduled to deliver 267 Liberty ships in 1942, was rendered instantly inadequate by the attack on Pearl Harbor, and the subsequent U-boat campaign along America's coast. 6.4 million tons⁴ of merchant shipping would be lost in the first half of the year, eclipsing the 5 million tons planned for completion by the Maritime Commission that year. That January, the target was raised to 8 million tons, with the target for 1943 set at 10 million. Expanding the yards to meet these targets, as had been done in 1941, was probably impractical. Instead, construction would have to be sped up, with the 250 day construction times of the first batch of ships falling to 105 days, with ships going from keel-laying to launch in only 60. That would allow six ships per way per year, a 50% increase over the pre-war schedule. Read more...

It is time once again for our regular open thread. Talk about whatever you want even if it isn't naval/military related.

The big naval news in the last few days is that Australia has torn up the agreement with France to build 12 new conventional submarines, and is instead pursuing SSNs, with aid being provided by the US and Britain. On the whole, this is a good thing, as SSNs are vastly more capable than conventionally-powered submarines, particularly in operations far from base, which is a major concern for the RAN. It's only the second time the US has allowed this kind of tech transfer, with the first being our deal with the British, started in the late 50s and still ongoing today. (Russia and France developed the technology independently, and have exported it to India and Brazil respectively.)

The only fly in the ointment is that the subs are to be built in Australia, because the government there has apparently not learned that treating defense primarily as a jobs program is a great way to run up the budget and delay the schedule. I initially expected them to get Astutes from the UK production line, but that would make too much sense. The announced detail doesn't say where the UK comes into the submarine program, but I wouldn't be surprised if they ended up with an Astute-based sub given how much strain the US nuclear shipbuilding industry is under.

Biden felt the need to clarify that while the submarines will use nuclear power, they won't be nuclear-armed, and I can see why he felt that way and despair about what it says for humanity. It appears that the highly-enriched uranium required for the reactor will come from the US, with appropriate safeguards to keep the Australians from misappropriating it for bombs.

2018 overhauls are the reviews of Salem and Nautilus, SYWTBAMN - Strategy Part 3, Falklands Part 6, the Nimrod Saga and Auxiliaries Part 3. 2019 overhauls are Riverine Warfare in Africa and South America, the 2019 Tinker Airshow, Falklands Part 18, Fire Control Transmission and Naval Ranks - Officers. 2020 overhauls are Operation K, Information, Communication and Naval Warfare Part 5, my first tests of missile defense in Command and Falklands Part 23.

Last year, I ran some tests using Command: Modern Operations to look at how the balance between ships and anti-ship missiles has changed over the years. However, I did so in a rather limited way, comparing US missile cruisers and destroyers against the SS-N-2/P-15 Styx missile. While this gave some interesting and useful information, I decided to broaden my scope, looking at both other missiles and other types of ship. I kept the basic setup from the first test, with a single ship off the coast of California, with 16 missiles fired at it. The defending ship would be the vessel most evenly matched against the missile attack in the first test, the 1991 (NTU) version of CGN-36, USS California.

To start, I re-ran my original experiment, with California facing down 16 SS-N-2/P-15 Styx missiles, fired from a bunker ashore, at a range of about 40 nm. At this range, the sea-skimming missiles pop up into radar range, then disappear again for a bit before the ship finally gets a good lock on them. The results were more or less in line with what happened during the first test: Read more...

The Standard Missile was originally developed to replace some of the USN's first SAMs, the Terrier and Tartar missiles of the 1950s. From the time it entered service in the late 60s, it was a success, with upgrades giving it more and more capability throughout the 70s and 80s. It was chosen as the primary weapon for Aegis, as well as arming older ships originally built for Terrier or Tartar. Variants were also produced, most notably an anti-radiation missile for use over Vietnam that also gave the USN an interim anti-ship missile capability in the 1970s.

An SM-2MR with a Fritz-X in the background

By the late 1980s, it was becoming increasingly obvious that the Aegis/Standard team would be incredibly effective against high-altitude targets, but less so against sea-skimming weapons. As a result, another version of the SM-2 was built, known as Block III and designed as RIM-66K/L/M (SM-2MR NTU/Aegis Mk 26/Aegis Mk 41) and RIM-67D (SM-2ER NTU). This version had improvements to the seeker and guidance sections to better pick targets out of sea clutter, as well as an improved proximity fuze. It was followed in 1991 by Block IIIA, which introduced an improved warhead and more fuze upgrades, but didn't change the designations. The end of the Cold War saw the NTU ships retired, mostly in the mid-to-late 90s, and the Mk 26 Ticonderogas axed shortly thereafter. This entirely killed off the RIM-67, and saw the RIM-66M as the only survivor of its branch, making things much easier to keep track of. It was the only version to get the Block IIIB upgrade, which saw an IR seeker added to give improved performance in an ECM-heavy environment, as well as probably some limited capability over the horizon, particularly against surface targets. Technically, both Block IIIA and Block IIIB remain the current versions, although there have been a number of upgrades over the years, including another new fuze and software changes to improve maneuverability. I suspect the version numbers have stayed the same as part of a designation engineering strategy. Read more...

In the late 60s, the USN's air defense systems were in crisis. While the first generation of SAMs, the 3T missiles, had been successfully introduced into operation, they were proving extremely unreliable in service, and the decision was made to upgrade the Terrier and Tartar missiles. These missiles used essentially the same forward section, with different motors and a separate booster for Terrier, and a new standard missile was proposed that would unify the medium range and extended-range missiles, changing only the motor and power supply⁵ between the two. For some reason, nobody thought to give it a better name than Standard, which remains in use to this day.

An SM-1MR is launched from frigate George Philip

In broad outlines, Standard was the same as the missiles it replaced, a rocket-propelled semi-active homing weapon designated RIM-66 for the MR (medium-range/Tartar replacement) version and RIM-67 for the ER (Terrier replacement). It used all of the same shipboard equipment, including launchers and guidance radars, as its predecessors, but the missile itself used all solid-state electronics, and replaced hydraulic actuators with electric motors. This meant that the warmup time dropped from 26 seconds for a late-model Tartar to only 1 second, while both missiles were deployed as "wooden rounds", requiring no tests over the 3-year interval between depot servicing. Range and altitude performance matched the predecessor missiles, 17 nm and 65,000' for RIM-66A SM-1MR and 40 nm and 80,000' for RIM-67A SM-1ER.⁶ An adaptive autopilot could handle any potential conditions of missile flight, regardless of altitude, airspeed or missile weight. Service entry came in 1968, and Standard rapidly began to replace the previous systems in service. Read more...