Abstractions are important for thinking about the world, and particularly for STEM types, taking a thing, putting it in a box and thinking about the box is basically what we do. If we had to reckon with the full complexity of everything at all times, nothing would ever get built. But as Joel Spolsky famously said, all abstractions are leaky, and the leakage can easily mess up any analysis if the person doing it doesn't know when things are likely to leak and how to deal with it.

I bring this up because outsiders attempting to analyze defense problems often make this mistake, particularly in the tech-adjacent sectors that I tend to see a lot of stuff from. Ideas go in the box, and then the box is folded, spindled and mutilated in complete ignorance of the gusher of complexity this produces. An excellent example of this is Austin Vernon's post on shipbuilding, where he attempts to diagnose the problems the USN is facing from a position of knowing very little about warships.¹ Read more...

In the Naval Gazing Discord recently, there was a discussion of the development of the Oliver Hazard Perry class frigates. Now, it's reasonably well-documented that the initial batch of Perrys were designed to carry the SH-2 Sea Sprite helicopter, but when the SH-60B Seahawk was introduced, the flight deck had to be lengthened to accommodate the bigger helicopter. This was done by extending the stern, which lengthened the hull slightly, bringing overall length from 445' to 453', although waterline length remained constant at 408'.

Rodney M. Davis, a long-hulled Perry showing the sloped stern

But while looking into this, I found a weird discrepancy in the reported displacement. My 1993 copy of Ships & Aircraft of the US Fleet gives the full-load displacement of the short-hull version as 3,658 tons, but says "except 3,900-4,100 tons for ships with LAMPS III modification". Now, this is a big, big jump, particularly towards the upper end of that range, which other sources often extend to 4,200 tons. When you're talking over 10% of initial displacement relative to full load, that's a lot and tends to really screw up the ship. It's rare that the designers leave that much margin, particularly in something like the Perry, which was intended as a pretty austere design. The even bigger question is exactly what was added. The difference between the two designs is fairly obvious if you know what to look for (the short-hulled ships have a pretty much straight stern, while there's a pronounced rake on the long-hulled vessels) but when the length is changing by less than 2% (and it should be a fairly light 2% because it doesn't go below the waterline) and the displacement changes by 10-15%, you start to wonder what is going on. The only other change noted in the books is the towed array, which is an SQR-18 on the short-hull ships and SQR-19 on the long-hulled ships.² Firm details on the SQR-18 are lacking, but the entire SQR-19 system weighs only 27 tons, so that's out as a cause of the discrepancy. 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.

Overhauls are Armor two, three and four, A Spotter's Guide to Modern Warships, Commercial Aviation Part 4, New Year's Logs and for 2023-2024, Iowa Ground Tackle.

To close off the year, I have a review of a pair of Danish Cold War forts, contributed by reader John Olsen, who previously wrote up the frigate Jylland.

In the early years of the Cold War, two coastal fortifications were built to close off Danish waters to Warsaw Pact maritime units. Both of them were closed after the Cold War ended, and both can be visited as museums today. This is a review of both museums, based on visits in 2023.

Stevnsfort Cold War Museum

Website

Introduction

Located well south of Copenhagen, the Stevns coastal fortification was one of two forts built in the early Cold War to close off Danish waters to Warsaw Pact maritime units. The primary armament of the fort consisted of two twin 5.9” guns from the WW2 German battleship Gneisenau, supplemented with 20mm and 40mm AAA guns. A HAWK SAM battery was added in the eighties (HAWK being an abbreviation for Homing All the Way Killer). Completed in 1953, the fort was formally closed in 2000, re-opening as a museum in 2008. Read more...

I've previously looked at all sorts of military aircraft from combat aircraft to helicopters, and we now come to the grab bag of types that round out the current inventory of manned military aircraft.

Maritime Patrol Aircraft

Oceans are big, and navies frequently have an intense interest in what is going on in them. For the last century or so, one of the best ways to discover this information has been the airplane, typically something fairly large so it can carry multiple crew and sensors. When techniques for hunting submarines from the air were developed, they were also given to these planes, which are typically converted airliners. They are also equipped to attack lightly-defended ships, although as converted airliners, you wouldn't want to use them against the enemy battle fleet. 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 for missing the last OT slot. I've been busy and just didn't get around to doing overhauls in time.

Overhauls are A Brief History of the Aircraft Carrier, Harpoon, The 6th Battle Squadron Part 2, Phalanx and for 2023, my review of Frontiers of Flight, Inc's Introduction to Artillery, Excitement in the Bab el Mandeb (sadly still relevant today) and The Problem with Air Museums.

Helicopters are terrible in many ways. They're noisy, they're slow, and they're expensive to operate. But they do have one major virtue. They don't have to be moving forward to fly, because they are so ugly that they repel the ground, which means they can take off and land vertically or hover over an area you want to keep an eye on. This is extremely useful if you need to operate somewhere that doesn't have a runway, either because there isn't space to build one or because you haven't had time to do so. This is a common problem that the US military faces, which means that they have a lot of helicopters.

General Transport/Utility

The most basic role of a helicopter is simply to pick people or stuff up and fly it somewhere else, and the majority of the military's helicopters do this. Occasionally, the place is just "over there, where there's a better view", although this role has largely been taken over by drones. For carrying stuff, it's often easier to use a sling load dangling underneath the helicopter, which saves you the trouble of having to land. This is generally not recommended if you're carrying people, although it is done in certain cases. Read more...

This time around, we turn our attention from combat aircraft and transports to the weird and wonderful world of support aircraft. The common thread here is information, either gathering it, moving it around, or denying it to the enemy.

AWACS

The US military has a lot of airplanes, and that in turn means it's generally a good idea to have someone coordinating all of them. It would be really helpful if that someone was mobile and had a really nice radar, and shortly after WWII, people realized that they could bundle the whole thing into an airplane, and thus was born Airborne Warning And Control Systems, or AWACS.³ It's an extremely useful concept, and they form a critical component of any serious Air Force. Read more...

I've previously given a brief overview of the US military's fighters and bombers, and it is now time to follow that up with an examination of the large and unglamorous fleet of support aircraft.

Transports

Airplanes are generally the fastest way to move things around, and the military needs a lot of things moved quite fast. Sometimes these things are bombs, and we use the planes we talked about last time to deliver them to unwilling recipients. But sometimes, the thing is people or trucks or other equipment, and bombers are not well suited to carry these. So instead, the military turns to transports of various kinds. Some of these are basically civilian airplanes with a new paint scheme and some military radios, while others are bespoke airlifters, intended to deliver big cargoes that normal airliners can't handle, such as tanks or paratroopers, to places normal airliners can't go. Read more...

I am going to attempt a very brief and somewhat opinionated guide to the aircraft of the US military, for those who don't marinate in military aviation. Obviously, there will be many simplifications for those who do, but they already know this stuff, so I will simply ignore them.

Before I go further, I should say a word on designations. The US military has a (reasonably) consistent way it designates airplanes. There's a letter or set of letters that tell the mission, a dash, then a sequence number for the specific type of plane, then a submodel letter for variants of that type. The mission letter(s) are things like F for fighter, B for bomber, C for cargo, H for hovering and so on. They can be combined, so you might use CH for a cargo helicopter and RB for a bomber converted to do reconnaissance. If a plane is given with two letter designations below, the first one is the standard single-seat version and the second one has two seats. For more details on the system, see here. Read more...