Recent years have seen a significant rise in the importance placed on anti-ship missiles, and the most prominent of these missiles has been the Naval Strike Missile (NSM)¹ developed by Norwegian defense contractor Kongsberg. NSM offers a major improvement in capability over legacy missiles like Harpoon and Exocet, and while competitor missiles have begun to emerge in recent years, NSM was good enough to be adopted not only by much of NATO but also by the United States, which is famously hostile to foreign systems.²

An NSM is launched

Norway had long maintained an indigenous defense industry, and it had been the first NATO power to introduce a proper anti-ship missile in the form of Penguin, a small weapon intended for use from missile boats and aircraft. As they were primarily expecting to use Penguin in coastal waters full of fjords and islands, the missile was equipped with an inertial navigation system to allow it to take advantage of terrain and fitted with an IR seeker instead of radar guidance, considerably reducing the odds that it would waste itself on a rock. Penguin was exported to a number of countries, including Sweden, Brazil, Greece, New Zealand, Spain, Turkey and, shockingly, the United States, who apparently didn't see it as worth the bother of developing an anti-ship missile for use by its helicopters. 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.

Apologies this is up late. Work has been busy, and I'm prioritizing the main posts.

Also, a reminder that all of you should consider coming to the meetup in Providence.

Overhauls are Classes, Aerial Cruise Missiles, The Proximity Fuze Part 1 and for 2023, my review of Top Gun: Maverick and Thoughts on the Chinese Balloon.

The USN's supercarriers are extremely capable, but also very expensive, and even the USN can only afford a few. As a result, every few years, the suggestion of building smaller, cheaper carriers comes up. In recent years, these have gotten louder, driven in large part by the development of the F-35B, which can operate without the need for catapults or arresting gear and offers capability unmatched outside the F-35 family. There have even been tests with USS America, normally an amphibious helicopter carrier, serving as a "Lightning Carrier". Unfortunately, there are serious practical problems with all of this. The simple fact is that there are major economies of scale in carrier aviation, and STOVL isn't going to remove them, nor is something like America, lovely though she is, a good substitute for the CVNs.

But where do these economies of scale come from? The first and simplest is the fact that steel is cheap and air is free. What really costs is not size, but capability. A full-capability carrier is going to need radar, big engines, defensive weapons, mission-planning systems and fancy communications gear, all of which costs a lot more than the bare hull, regardless of the size of the carrier. Not to mention things like catapults, arresting gear, and heavy maintenance facilities, all of which need to be onboard to make a conventional carrier regardless of the size of the air group. Nor is the air group going to scale linearly. Sure, you can cut the fighter complement from four dozen to two dozen, but there's going to need to be some minimum number of fighters kept for self-defense, and since the threat doesn't halve for a smaller carrier, that might not be something you can cut too much, leaving fewer than half of the previous complement for strike missions. Things are even worse for the rest of the air wing. The complement of E-2 Hawkeyes (typically 4-5) is set by the need to keep one airborne at all times while allowing maintenance, and the size of the MH-60R detachment similarly comes from the need to keep a helicopter or two active to hunt subs. The EA-18G and MH-60S detachments could be cut, but you're still looking at needing more than half of the carrier wing for less than half the capability. Read more...

I've previously discussed Standard, Sea Sparrow, ESSM and Phalanx, but there is one last air-defense weapon that deserves discussion. This is the RIM-116 Rolling Airframe Missile, better known as RAM.

A RAM is launched from USS Green Bay

Much like the other point-defense systems, RAM's origins trace back to Eilat, and the panic that it provoked within the USN. It was conceived to work in pretty much the same niche as Phalanx, providing a last-ditch defense against incoming anti-ship missiles. Effective as it was, Phalanx had a serious limitation, even while it was still in development. The use of a gun limited effective range to no more than 1500 yards, which was a serious problem in the face of supersonic missiles. The available window to engage such a weapon was short, and even if the Phalanx did shoot it down, the debris was likely to strike the defended ship. The obvious solution was to use a missile, which could engage at significantly longer range. Read more...

It is time once again for our regular Open Thread. Talk about whatever you want, so long as it isn't Culture War.

The jury has deliberated, and despite fierce compeition for 2023, the William D Brown Memorial Award for the biggest screwup that didn't kill anyone goes to the USN and VP-4 for running a P-8 off a runway and into the ocean. Runner-up status goes to all of the various commanders removed throughout the year. I can't find an exact count offhand, but it was a lot of them.

Overhauls are Aegis, Missile Guidance and for 2023, Hornet Parts two and three.

I've previously looked at the development of the shell fuze from the earliest days through WWII. But all of those were intended for use against surface targets, and during WWI, a new threat emerged, that of the airplane.

A powder time fuze's internals

This led to a reemergence of the time fuze, as the sky was very big and planes were small, and setting off the shell when it should be near the target was a lot more effective than hoping for a direct hit from heavy guns. This was surprisingly easy, as time fuze development had continued for use with shrapnel shells.³ The mechanism was surprisingly similar to some of the early time fuzes, but far easier to use. Essentially, the nose fuze had two horseshoes of delay composition which could rotate relative to each other, with a vent between them to allow the combustion to spread from one to another. To set, the operator (who was quickly replaced by a mechanical setting machine) merely rotated the nose section to the correct position, then loaded the shell into the gun, where the setback force would start the powder burning in the upper ring. Once it reaches the vent, it spreads to the lower ring, where it burns back towards the detonator. Minimum fuze time was generally limited for the safety of the crew (1.8 seconds was the US standard), but the use of setback to start the fuze train (even if a centrifugal safety mechanism would keep it from going off) meant that dropped time fuzes were particularly dangerous and generally needed to be thrown overboard immediately. Some early time fuzes also had a secondary impact detonator, although this seems to have become less common as dedicated AA time fuzes were developed.⁴ Read more...

With the development of the delay impact fuze, the basic form of fuzing for AP shells was set, and a number of nations appear to have simply gotten fuzes they liked in the early to mid 20s and then stopped developing them. The major exception was the US, always paranoid about things that might go boom. Pretty much all US fuzes⁵ had at least two if not three independent mechanisms for making sure that nothing went boom before it was supposed to.

A standard USN base fuze

The standard US base fuze (which came in several Mk variants depending on the caliber of the shell, the main difference being the length of the fuze delay) was a complicated device, carefully designed to not arm until the right moment and as a result baffling in its complexity. There were the usual safety pins pulled out by centrifugal force, some of which were held in place while the shell was still in the barrel because setback pushed the sensitive firing pin onto them. The impact force pushed the fuze plunger forward, aligning the holes through which the detonator's flash would pass into the booster and bringing the sensitive primer onto the sensitive firing pin and setting it off. Instead of directly setting off the delay element, the gas from the sensitive primer locked the plunger in the forward position (thus ensuring that the holes would remain aligned even while the delay was burning) and freed the secondary firing pin to impact the secondary primer, which in turn set off the delay element. When that had burned (which took between .01 seconds for 6" shells and .035 sec for battleship shells) it set off the detonator. Some of this complexity was probably to improve fuze reliability during oblique impacts, which could otherwise fail to set off a shell because things get pushed out of alignment.⁶ This fuze worked quite well in general, although it was soon discovered that fumes from the explosive filler of the shells tended to corrode the fuze internals after 6 months or so, a problem ultimately solved by providing a Bakelite coating. Read more...

It's time once again for our regular Open Thread. Apologies this one is late, I got distracted with other things. As usual, talk about whatever you want, so long as it isn't culture war.

One of the things I got distracted with was the book, which I've been making more progress on revising. Hopefully I can keep the momentum up and get it finished in the next few months.

Second, remember that the 2024 Meetup is coming up in New England. We still have some slots available, so sign up if you want to come see ships with me.

Overhauls are Bringing Back the Battleships, Carrier Doom parts two and three, The Ticonderoga Class, The Virginia Class, and for 2023, Miramar 2022 and Hornet Part 1.

Any explosive shell requires some mechanism to set it off, preferably on impact. Early shells had been forced to use time fuzes thanks to the difficulty of designing a safe impact fuze for a round shell that might strike in any orientation, but after the introduction of the rifled gun, it was possible to make a fuze that was generally safe until it was fired and set off the shell immediately upon impact. But they generally relied on a pin or wire that sheared on firing to keep the striker from setting off the detonator, and it was entirely possible that if the fuze was struck or dropped, the strike would break loose. Orders were given to disarm and discard any fuze which was struck or dropped, but the possibility of accident was never too far away.

The solution was to look at the various forces imposed on a shell when it was fired. The shock of firing, known as setback, had been used from the start, but it could be duplicated by accidents. Harder to duplicate was the centrifugal force produced by the shell's spin,⁷ because it pushed on different parts of the shell differently. The solution was to restrain the striker with two or more spring-loaded safety pins,⁸ so that even if a shock was to temporarily dislodge one pin, the other(s) would remain in place. The fuze pictured above has a secondary centrifugal safety feature in the form of a separate firing pin, which is normally concealed within the striker and held in place by the safety pins. When fired, the setback holds it concealed within the striker, and after it leaves the muzzle, the centrifugal force swings it into the unlocked position, a device to make the fuze "boresafe". Also worth noting in this fuze is the creep spring, which is designed to counter the force produced by air resistance on the shell and keep the striker at a distance from the primer until the shell actually hits something.⁹ Read more...

One aspect of battleship ammunition that I have not discussed very much (with one notable exception) is fuzing, the process of making shells go off at the appropriate time. But this is a critical part of gunnery, as a shell that doesn't go off is of very little use, while a shell that goes off early is potentially disastrous. Designers have to meet both of these challenges while also keeping the fuze compact and setting it up for best effect against the target.

An early tubular time fuze

The earliest shells used time fuzes, which at their core were tubes of packed gunpowder calibrated to burn for a specific length of time after being ignited by the powder gasses on firing, in the hope that they would go off after the shell was lodged in the target. This posed a number of problems. First, shells that bounced off or broke up on impact would do no damage, and there was even the possibility that a very brave man could douse a shell's fuze or throw it overboard. Second, the packed gunpowder was easily damaged by the force of firing, particularly on the early wooden-cased fuzes, which would tend to expose more surface area and cause the fuze to detonate early. Third, the burning fuze could be snuffed out on impact, a particular problem if it ricocheted off the water before reaching the target. And fourth, while the burning time could be adjusted by cutting the fuze tube, and most fuzes, whether metal or wood-cased, were marked to accommodate this, it was a rather involved process in the heat of battle, particularly because the fuze then had to be inserted into the shell before the gun could be loaded. Cutting fuzes could be eliminated by supplying each shell with a number of different fuzes cut and formulated to burn to different times, but that didn't solve the problems of needing to fit them to the shell in action. And of course the exposed fuzes were vulnerable to mechanical damage or water. Read more...