Thursday, December 8, 2005


A few days ago, a friend (Rick Pugh) asked if I’d be interested in visiting the Midway Aircraft Carrier Museum on Pearl Harbor Day. Absolutely! was my answer, and we were actually able to pull this off. We started by having a very nice breakfast at a place with an unlikely name: “Hash House a go go”. I can’t account for the name (no “go go” in evidence), but the food was very good; memorable, in fact. I am planning to go back there with my lovely bride one of these fine days…

Anyway, after fortification we set off downtown to the Navy Pier, where the old USS Midway is now permanently docked. Parking was easy; plenty of room on the pier itself (though it’s cash-only, and I had to bum some bucks from Rick). We were on board in just a few minutes, with a minimum of fuss, and there were no crowds. Bad for their business, but good for us!
We first took a tour of the island, on the advice of the first (of many!) helpful and knowledgable docents we ran into. He told us it was likely to get crowded and hurried as the day went on, so we took his advice and went on the first island tour of the day. The large photograph at right is a panoramic view (made from three individual photos) from the “air boss” position high in the island. The island is on the starboard (right) side of the ship, and you’re looking aft (toward the rear) through about amidships (directly across). From left to right, the aircraft visible include a COD (nose and port wing), the nose of an S-3 Viking, (almost hidden behind the awning) an F-14 Tomcat, an F/A-18 Hornet(in the background, in desert colors), an F-4 Phantom, an A-6 (foreground), an RA-5 Vigilante (background), and an H-3 SeaKing. And there were even more aircraft on the flight deck forward of these, and a few more on the hangar deck! The smaller picture at right is Rick sitting in the Air Boss' chair, looking out over the flight deck…
The photo at right was taken from near the bow, looking aft on the flight deck. In it, left to right, you can see another F-4 Phantom, an E-2 Hawkeye (with it’s wings folded, and the radome “flying saucer” on top), and an A-7. To an old Navy electronics guy like myself, there are some interesting things on the mast over the island: an SPS-10 radar antenna, and an SPS-48 radar antenna. The SPS-10 is a truly ancient piece of gear, of World War II vintage — tubes and prehistoric servos. They were laughably old — and belonged in a museum — when I was in the Navy (in the '70s), but a docent told me that it was still in service when the Midway was decommissioned in 1992. The SPS-48 is a considerably more modern system, but still quite old. It was one of the first of the so-called “3D” radars to be deployed. By “3D", they mean that in addition to bearing and distance (what most radars do), it also detects the altitude of a target. It does this by using a fixed-array antenna that is scanned in elevation by changing the frequency of the transmission — a relatively simple, but easy and reliable, fixed-array antenna technique. Since the fixed-array scans only in elevation, the antenna still rotates to scan in azimuth.
At right, from left-to-right: the F/A-18 Hornet, Rick looking at the big radial piston engines on the COD, an F-4 Phantom procedures trainer, and an A-4 Skyhawk on the hangar deck. This was the first time I’d seen an F/A-18 up close and personal; I was struck by how much more advanced the construction was compared with any of the other aircraft on board. Virtually every piece of its fuselage and wings are compound curves; everything is very smooth, with a nearly complete absence of the usual angular protuberances. Very impressive, even just to the casual eyeball. In my Navy career I made quite a few trips to-and-from carriers at sea; most frequently the USS Enterprise, and almost always by helicopter. But once — just once — I flew in the back seat of an F-4, catapult-launched from the Big E (and landing at Cubi Point, Subic Bay, Phillipines). That was a serious kick in the pants, especially after the pilot learned I was interested in aerobatics, and we did a few things that I suspect weren’t in the original flight plan. And twice I landed on the Big E in a COD. Now the COD is a small, rugged plane with a relatively low landing speed — so a carrier landing in a COD is a very far cry from a carrier landing in, say, an F-4. But I’m here to tell you that it was plenty exciting for me. The most memorable part, for me, was the initial approach to the carrier — it looked like such a tiny speck, lost in the vast ocean, and landing on that speck just didn’t seem very likely. Or very wise. Naturally, the pilots made it seem like a cakewalk…
Last, but certainly not least (for me, anyway!) — at right is Rick standing next to a system that I am very familiar with: a Univac CP-642B computer. This particular computer is part of a complete Ship’s Inertial Navigation System (SINS). I trained on this system, and in fact even helped debug some software on it, way back in the early '70s. This was the first inertial navigation system deployed on US ships, and for its day was quite a remarkable system. An inertial navigation system is one that figures out where it is by very precisely measuring every movement it has made since leaving another precisely known place. By integrating all those movements over time, it can calculate exactly where it is at any moment. In practice, inertial navigation systems were built back then by combining a “stable platform” and three accelerometers. The stable platform is a system of three or four gyroscopes, mounted on different axes, and it always points in the same direction (it’s mounted on a gimballed platform to allow this), no matter how the ship twists and turns. The accelerometers measure every teensy little acceleration (speeding up or slowing down) in the three different directions (usually thought of as left/right, forward/backward, and up/down). With a little math and that information, you can figure out where you are — and that’s exactly what SINS does.
For me, though, the most interesting part is the CP-642B. You see, that was the first computer I ever worked on; the first one that I ever understood. By today’s standards, it is almost humorously incapable: 30 bit word length, a blazing 100KHz clock speed, and 32 kilowords of excruciatingly slow (and tempermental) magnetic core memory. But this is what I cut my digital teeth on, and so I have a sort of sentimental attachment to the beast. I haven’t seen one of these things for close to 30 years, so I was quite surprised to discover that within moments of walking up to the thing, I could remember all kinds of details about how it works, and how to operate it. I do believe I could still key in a program, run it, single-step it, and so on. For any geeks out there: that control panel with all the lights is something you just can’t have these days. There’s a light for every bit in every register in the computer, and you can press that light to toggle the state of that bit. A momentary paddle switch allows you to stop the computer’s execution at any point, and then you can see the complete internal state of the computer at that moment. Very primitive — but it’s amazing what we managed to get done with this machine…


  1. In the old blog, Rick said:
    I worked on his very computer during my Midway tour(1989-1991). I went to see the museum with my kids around 2002, and was surprised to see not only the SINS space open to the public, but my original reloading procedure notes still taped to the plexiglass control panel cover!- Rick “Roz” Orozco, DSC(Ret), Montana

  2. Hi, Rick! Thanks for leaving the comment on my lonely post… I confess to being amazed that you were STILL using a 642B in 1991! I had a 642B emulator running on a PC long before that (way, way faster than the real deal, too)… You don’t happen to have a rep card for that thing, do you?

  3. Hi Rick, Midway was my home from 1972-1975. I worked in the Carrier Air Traffic Control Center (CATCC) using radar displays driven by the NTDS CP-642B, with interfaces to the Automatic Carrier Landing System (ACLS). Here is a link to a picture of an ACLS (SPN-42) console (on Midway circa 1973) at my blog:

    In 2004 I visited Midway museum. She looked and smelled much the same.

    Thank you for the story and pics!
    More about her as a museum:

  4. I too was a SINS Tech, aboard the USS Nimitz. I got off the ship in 1980 and the CP-642 was still the SINS computer. See pics ad USS Nimitz.