On April 9th, 1940, Hitler unleashed his forces on Norway and Denmark, hoping to preempt Allied moves into Scandinavia. The plan was to land troops in several strategic cities, using the warships of the Kriegsmarine as transports. The assumption was that the Norwegians would put up at most token resistance, allowing the Germans to get ashore easily, but this was dramatically disproved at Oslo. The force there, led by the heavy cruiser Blucher, managed to get past the outer defenses, but the commander of the inner defenses at Oscarsborg chose to fire, sinking the cruiser with his guns and torpedoes.

HNoMS Olav Tryggvason

But even as Blucher burned, ultimately rolling over and leaving much of the invasion force scattered on the shores of the Oslofjord, the other German ships continued to carry out their mission, some of them having split off before the main force reached the Drobak Narrows and Blucher fell victim to Oscarsborg. One of these was the detachment sent to seize the main naval base at Horten, in the outer reaches of the fjord. It was composed of two torpedo boats, Kondor and Albatros, fast minesweepers R17 and R21, and auxiliary Rau VII. Horten was the headquarters for the defense district protecting Oslo, but the guns intended to guard it were not manned, and its only real protection was the minelayer Olav Tryggvason, recently released from overhaul, and minesweeper Rauma. The German vanguard came in aboard the minesweepers as dawn was breaking, taking the Norwegians, who thought they'd have more warning from their ships patrolling offshore, by surprise. R17 managed to get all the way to the pier before Olav Tryggvason opened fire, the 70 or so men aboard her capturing a pair of Norwegian AA machine guns before the minelayer started pumping shells into the German ship. Three hits left her completely ablaze, and she sank when the fire reached her depth charges. Read more...

Nothing particular to say for this week's open thread (beyond the usual rules still being in effect), but I am very much looking forward to seeing those who are going to be coming to the Iowa meetup tomorrow. I'll be wearing a bright green hat with the Naval Gazing logo on it.

Also, it seems likely that the East Coast meetup this year is going to be in DC instead of Philadelphia to coincide with the DSL meetup. I'd like to do the Museum of the US Navy, but that's on Washington Navy Yard, so getting in on a weekend doesn't seem feasible. Any suggestions?

2018 overhauls are Rangefinding, So You Want to Build a Modern Navy - Aviation Part 2, The Great White Fleet Part 1, The Newport Conference and the US Dreadnought, my review of Batfish and Falklands Part 4. 2019 overhauls are Information, Communication and Naval Warfare Part 3, dndnrsn's review of Bavarian military museums, Rangekeeping Part 2, Impressment, my review of the National WWI Museum and Signalling Part 1. 2020 overhauls are the Goat Locker picture post, Coastal Defenses Part 4, The Pearl Harbor Rant and Mike Kozlowski's review of Fort Monroe.

On the night of April 8th, 1940, the population of Norway slept soundly, unaware that the might of Hitler's war machine was poised to crash on their shores. Warships loaded with troops were just off the country's major cities, hoping to seize them with minimal opposition thanks to the low readiness of Norway's military. The official justification for the German operation was the Allied mining of Norwegian coastal waters to stop the flow of iron ore out of the port of Narvik, although the first German ships sailed before the British did.

Blucher on the way to Oslo

The main target of the German invasion was the capital, Oslo, which would be taken by 2,600 troops carried aboard the brand-new heavy cruiser Blucher, "pocket battleship" Lutzow, light cruiser Emden and three torpedo boats, Albatros, Mowe and Kondor, joined by a batch of R-boat minesweepers. They had sailed from Kiel early that morning, as they had by far the shortest distance of the various forces to go, although the passage wasn't entirely smooth. While transiting the Kattegat, torpedoes were spotted and successfully dodged. They came from the British submarine Triton, which quickly reported their presence to the Admiralty. More submarines were sent into the area, but none were able to attack before the Germans reached the Oslofjord, the long inlet that leads to the city. Read more...

WWI was a war of artillery, and all of the powers involved quickly discovered that they were short on heavy guns. The easiest way to plug this shortfall was to turn to the existing sources of large-caliber artillery, naval and coastal defense weapons. As these were not designed to be mobile, the only real option was to use the best way of moving heavy cargo around, the railways.

USN 14"/50 Railway Gun

The majority of these guns were manned by crews taken from the units that would normally have operated them, and ranged in size from 6" to as much as 15". Because they were made from second-hand guns, a vast array of types were built, most in relatively small numbers. The British made extensive use of their standard 9.2" gun, long a mainstay of coastal defenses, while the US rushed to fabricate railway carriages for a variety of weapons, including almost a hundred 12" mortars from Endicot-period batteries, as well as 8", 10" and 12" guns from the same era. Only a handful made it overseas before the end of the war, and the story of American railway artillery was instead dominated by five USN 14"/50 naval guns mounted on railway carriages that spent two months in action during the closing days of the war. Read more...

The Soviet Union was not alone in looking at building battleships after WWII. The US and Britain both also took looks of varying seriousness during and after the war, drawing on their combat experience to fix the problems of the wartime battleships. The common thread throughout these designs would be an increased focus on the threat from airplanes instead of other battleships.

The final Montana design

Formal US design studies ended in mid-1942, and looked at variations on the basic Montana class, with thicker decks and better AA arrangements. The need for protective decks was seen as particularly acute early in the war, before it became obvious how difficult it was to hit a moving target from high altitude, and the Bureau of Ships looked at reducing the belt to Iowa thickness in exchange for increasing the total deck thickness from 9.24" (equivalent to a single thickness of 7.3" when the different layers were taken into account) to 10.4" (equivalent to 8.3"). This new deck would be enough to keep the US 14" AP bomb out if dropped from anywhere below 19,000'. Other sketches were prepared that accepted a reduction in speed in exchange for an increased AA armament, with better sky arcs than that planned in the existing sketches. By the standards of 1944, even the increased AA armament seemed hilariously lacking, with 16 5"/54s, eight twin Bofors and 24 Oerlikons. One all-machine gun design was even considered, apparently a result of fleet dissatisfaction with heavy AA fire control early in the war, although no details seem to have survived. Read more...

One of the problems that had to be solved when missiles first went to sea was how to carry and launch weapons that were not only bigger and heavier than anything that had previously been carried aboard, but also fragile and complicated, and which had to be fired in quick succession. To make matters worse, each ship could carry only a limited number of missiles, so provisions were also needed for replenishing weapons at sea.

USS Oklahoma City showing her Talos launcher and radars

As the Terrier and Talos missiles had separate boosters, the initial plan was to store the majority of the missiles broken down to fit as many as possible aboard. The problem was that this would sharply limit the rate of fire after the ready-service missiles had been expended, and it soon became clear that the missiles could generally be stored assembled. To shrink the space required, they would be stored without fins, which only took 15 seconds or so to install by a dedicated crew in the last space before the missile was rammed onto the launcher. This wasn't likely to be a serious limitation on the firing rate, as each missile or salvo required a dedicated illuminator throughout its flight. But that still left the question of how to store and transport the missiles, and the Navy came up with a number of different solutions, many of which were installed on various ships. Read more...

It's time as usual for our biweekly open thread. Talk about whatever you want, so long as it's not culture war.

I have a book recommendation for you this time. On Yankee Station is an account of the naval air war in Vietnam, and it's a splendid mix of personal anecdote, clear historical analysis and tactical primer. It's probably going to be my first recommendation for an indictment of the conduct of the war, particularly as it's relatively short and very well-written.

2018 overhauls are Pungdo, So You Want to Build a Modern Navy - Aviation Part 1, Jackie Fisher, Battlecruisers Part 2, Did Iowa Move Sideways During a Broadside? and Auxiliaries Part 2. 2019 overhauls are Soviet Battleships Part 1, Alexander's review of the Newark Air Museum, Battleship Aviation Part 4, Lord Nelson's review of Soya, The Scuttling of the High Seas Fleet and The Blockade of Santiago. And 2020 overhauls are Merchant Ships - Specialized Tankers and Cargo Ships, Naval Rations Part 1 and Tom Clancy.

The six months after the Fall of Poland in October 1939 were known as the phony war or sitzkrieg, as both sides sized each other up. The first crack in this came in early April, when the Germans invaded neutral Denmark¹ and Norway, driven by a combination of Hitler's paranoia about the Norwegians cooperating with the British and a real Allied plan to intervene in Norway to stop the flow of iron ore to Germany. Despite several warnings, both the Allies and the Norwegians themselves were unaware of the coming invasion, and the Norwegian military was still badly hamstrung by low budgets and a lack of manpower.

The German invasion plan

The German plan involved seizing the key cities of Norway: Narvik, Trondheim, Bergen, Kristiansand and Oslo, using troops carried aboard warships. The Germans generally didn't think the Norwegians would fight much, and if they did, their low readiness would let the prepared German troops win despite lack of numbers or specialized amphibious shipping. Follow-on units would be available almost immediately thanks to merchant ships that had been sent out before the faster warships departed Germany. Surprisingly, despite some of the transports passing through Norwegian coastal waters, security held. Read more...

When WWII broke out, Hitler had no plans for Scandinavia. The Nordic nations had proclaimed neutrality, and he had his hands full with operations closer to home. But this began to change thanks to a visit from a Norwegian Nazi named Vidkun Quisling in December 1939, who claimed that the Norwegian government was conspiring with the British to join the Allies. Hitler ordered plans be made for intervention if this was true, and these were accelerated in the wake of the Altmark incident in January 1940, which convinced him that Quisling's accusations were true. Orders were given to implement what was known as Operation Weserübung.

Vidkun Quisling

The basic plan was fairly simple. The assault force would be carried by various warships of the Kriegsmarine, as the Germans were lacking in landing craft. Two regiments would be landed around Oslo, in connection with an airborne assault, while one regiment apiece was detailed to Bergen, Trondheim, Narvik and Kristiansand. Reinforcements would come by transport, some of which would have to be dispatched well before the warships. The biggest threat foreseen was intervention by the Royal Navy, and there was considerable friction between the Kriegsmarine, who wanted to withdraw the ships as quickly as possible, and the Heer, who wanted them left to protect the forces ashore, at least until they could make the Norwegian coastal defenses operational. Ultimately, the Kriegsmarine largely won. The Lufwaffe proved its useful cooperative self, and Goering refused to place his forces under unified command, while the other services were skeptical of his claims that the bombers would protect them from the RN. Read more...

In 1945, the US Navy faced a serious problem. Even before it faced the hell of the kamikazes off Okinawa, the introduction of jets and the threat of the air-to-surface guided missile, first shown by the Germans, was enough to start them searching for new ways of protecting the fleet.

The Lark missile

The obvious answer was a surface-to-air missile, one hopefully capable of shooting down the attacking aircraft before it got within range. Both the Bureau of Aeronautics (responsible for aircraft) and the Bureau of Ordnance (responsible for guns and torpedoes) were interested in the problem, and began separate programs. BuAer managed to get into the air first with Lark, intended as an emergency counter to the kamikazes, but the subsonic missile used liquid propellants, which tended to make naval officers nervous due to the risk of a spill, and ran into formidable guidance problems, which it helped solve before becoming obsolete. Read more...