Has anyone any idea who 'Dr Sell' was, who accompanied Dr Lyman Parratt, from the USA, for MAD trials at RAF Helensburgh in 1943? I am referring to a Dr Sell mentioned in notes by my late father and 'Dizzy Cooper' (test pilot) with the MAEE. I know a Dr Maurice Bell, of the USA, was involved in anti submarine/Catalina trials. Could Dr Bell be Dr Sell? MAEE and the USA worked closely on MAD. I know it is a long shot but has any one ideas? Was it Sell, Bell or a.n.other? robin bird
Author question: Can anyone describe or give me a link to an image of a Magnetic Anomaly Detector screen on an American ASW aircraft?
Cool pic, Robin Bird. Thanks! Can you describe the equipment? Would a B-25 crewman be listening to a tone like sonar, observing some sort of digital scale or viewing a screen to determine depth and location of sub?
Although slightly different from the MAD shown in an earlier post, there's a technical manual for the AN/ASQ1 MAD here:- www.dtic.mil/dtic/tr/fulltext/u2/b810592.pdf 610
Sorry I am not sure how USA observed MAD waves. My dad was the official photographer for trials of MAD by the Marine Aircraft Experimental Establishment, RAF Helensburgh, using Catalina FP258. A tail cone and Mark X console were installed with a hull hatch modified for a winch and a tow bird cradle support. The latter was not successful as the cable broke and the equipment was lost in the sea.
To markos88. The operator displays in the American AN/ASQ-1 were a centre-zero meter and a chart recorder. Looking at the manual the meter alone would be used by a small single-seater aircraft whereas a larger plane would have an operator/observer who would tend the chart recorder and annotate it. I would guess systems with a screen and digital readout would be introduced after WW2. I don't see any mention of an audio tone on the AN/ASQ-1 but it would have been feasible, although making the equipment more complicated. I worked on 1960-70s versions of the MAD, or magnetometer, for marine use locating things like the older powered undersea cables (pre-fibre-optic cables) and also dumped ordnance. This was towed well behind the ship to be clear of the ship's magnetic anomaly. The equipment was fitted with a form of digital readout using Nixie tubes but the hardcopy of the readout was still printed on a chart recorder. Modern systems send a data stream to a logging computer but a virtual chart-recorder-type display is still used if required. '610
from British WW11 MAD notes: The recorder provides a permanent inked record. A visual indicator is positioned on top of the pilot's instrument panel to provide a visual indication of the MAD signal
This is exactly what I was looking for. Thank you so much Robin Bird and BC610E! In my history-inspire novel about The Battle of the Atlantic in 1942, my American protagonist is flying a B-25 out of Florida on antisubmarine warfare (ASW) patrol. I suspect the MAD operator would be reading the deflections of the remote signal meter rather than a print-out - which to me (a retired physician) looks much like an EKG recording. With early introduction of radar in 1942-43, the bombardier operated that equipment. But I wonder if this MAD device would be managed by the navigator or radio man??
On December 15 1942 the UK War Cabinet noted there were two MAD types available, however the US Navy had not yet decided which one to use. Despite trials at Helensburgh in 1943 a decision was made not to install MAD in RAF Coastal Command aircraft. Not just because of reliability but because of UK waters had few suitable straits or channels to use MAD effectively. It was left to the USA to introduce MAD first. Notes regarding an attack by a MAD CAT on U 761 in February 1944 indicates that there was an operator of MAD
Looks like Robin has answered your question about crewing very thoroughly! The sighting report gives some interesting detail on a MAD sweep by two a/c. As regards the chart readout, the meter alone would be fine to indicate an anomaly but I suggest that the chart recorder helps estimate the size and therefore the proximity of a target by giving a record that is easily compared with those from adjacent search lines. My marine experiences with magnetometers are that an anomaly could appear, peak and then die away very quickly, so might be missed, or the size misjudged, if just a visual watch was kept. Remember too that a ship carrying out a MAD sweep would be very much slower (<5kts) than an aircraft doing maybe 150 kts or so, so the operator had to react quickly. One drawback I can see with the chart recorder is that a big anomaly could drive the pen off scale if the system gain was set too high, making the size estimate difficult. Of course, in that instance, the meter would go hard over and give the same result. The early marine magnetometers partly overcame this by having two coloured pens, one to give say 0-100 gamma scale and a second scale of 0-1000. I see the example charts in the AN/AQS-1 book are expressed in gammas, nowadays we'd use nanoTeslas, IIRC. Veru interesting that the UK didn't adopt MAD. It wasn't a huge success from what little I've read, radar and Ultra having much greater success with the U-Boat war. Regards '610
Thanks very much, Robin and BC610E ! The B-25 Mitchell I'm writing about had a pilot, copilot in the cockpit, bombardier in nose bubble, radio man and navigator in the cabin aft of cockpit (no tail gunner). I understand the bombardier was trained to use the new radar equipment in the nose bubble (actually installation was a bit later than I say ~ writer's prerogative for story line). I'm not sure MAD equipment could also be in the nose bubble - more likely aft of cockpit with navigator or radioman?? My understanding is the MAD equipment didn't really function too well unless the aircraft was directly above the U-Boat - and as you note BC610E, that would only be a brief moment. Here's what I have written at several points in my novel. Does it sound OK? Any suggestions or corrections would be greatly appreciated. re: eyes fixed on the glow of their fluorescent screens maybe "remote signal meter" or paper strip???? ................ February 1942 meeting with a blimp officer in Jacksonville “What brings you to Jacksonville?” Ramón asked. “Just an overnight at the Naval Air Station," Adam said. "I’m on a test run from Lakehurst down the coast with some new equipment.” Ramón leaned forward. “What kind of equipment?” Adam lowered his voice. “Well, of course this is top secret.” He paused and smiled. “Though I’m sure the Krauts know all about it.” “Anything new sounds good to us,” Ramón said. “Hell. We just got depth charges last week. Other than that, we’ve got zip.” “No radar. No nothing,” Erik said. “We just fly in circles out there.” “Yeah,” Ramón said. “Then the goddam U-Boats sink ships right under our nose at night.” “How the hell do you see anything at night?” Adam asked. “Good question,” Erik said. “If a ship’s been hit, we go out with the Navy,” Ramón said. “Sub chasers and destroyers cruise around and we drop flares if we see something.” Adam shook his head. “So most of the time you’re just out there relying on visual contact?” “That’s about the size of it,” Ramón said. Adam leaned in close and lowered his voice. “Well, that’s the nice thing about the blimp I’m on now. We’ve got radar and a magnetic anomaly detection (MAD) device.” “Really? How’re they working out?” Erik asked. “Radar’s good for detecting a large ship at 15 miles and a periscope at five. Then, if they dive, the MAD device is good for about 400 feet.” “Wow! That sounds pretty nifty,” Ramón said. “Yeah. If we’re right on top of them,” Adam said. “But subs are a lot smaller than ships. And I’ll be damned if they don’t go underwater.” He pulled on his cigarette. “Radar picks up big ships a hell of a lot better than subs and the MAD device often gets false signals from the ocean floor.” “Well shit,” Ramón said. “Are you guys going to be any more use to us than the Hooligan Navy cruising around out there in their pleasure boats?” ............... June 1942 Camagüey Cuba During the past month at Langley Army Air Force Base in Virginia, Sizzling Rita had been equipped with an extremely accurate absolute altimeter, air to surface vessel radar (ASV), a magnetic anomaly detector (MAD) and new depth charges configured to explode within the kill-radius of a diving U-Boat The bombardier Angelo was trained to operate the radar equipment, while Ramón and Erik learned killer-hunt tactics from the newly-established First Sea Search Attack Group, known commonly as the Search. ............. June 1942 Camagüey Cuba Erik stirred his coffee slowly. “Damn! I don’t know, Ray. All this new equipment and the goddam Krauts still got away yesterday.” Ramón dipped into the sugar and nudged the bowl across the table. “We came close, Erik. I think we’re a hell of a lot better since joining the Search.” “Maybe our tactics. But I’m not so sure about the equipment, Ray. Spiffy new radar’s fine as long as the U-Boats don’t dive. And the goddam MAD equipment doesn’t seem to detect shit unless we’re right above the target.” “I’m not too jazzed about MAD either. We’d never have found that U-Boat yesterday on our own. We were lucky the destroyer picked them up on sonar.” “Yeah. But not for long.” Ramón grasped Erik’s forearm. “Look, buddy. We’re getting closer. I can feel it. It’s just a matter of time.” ............... June 1942 Camagüey Cuba With Rita’s roaring engines muffled by his headphones, Ramón reviewed his strategy. If the U-Boat was still on the surface, airborne radar would function until about a mile from the target. Then the signal would be lost in the unwanted echoes of sea clutter. More likely the Krauts would already be submerged. But with a maximum underwater speed of seven knots, they couldn't get far from the attack area. Ramón would have to rely on his MAD device. Joining the Search off the Bahamas at 0110, Sizzling Rita flew 500 feet above the ocean in tandem with the B-18 Bolos out of Key West. Like a flock of nocturnal raptors, eyes fixed on the glow of their fluorescent screens, the medium attack bombers swept back and forth over the ocean, searching for the magnetic anomalies of their steely, underwater prey. Below, sonar-equipped Coast Guard and Naval vessels trolled the sector in a parallel pattern. At 0400, running low on fuel after three hours without contact, Sizzling Rita was replaced by a B-18 from Key West and returned to base. .................. June 1942 Camagüey Cuba Squadron Leader Richardson smiled as they approached his table. “Well well. Nice to see you lads again. Jacksonville wasn’t it?” He glanced around at the empty tables, then at their uniforms and flight jackets. “Just returning from a mission?” He asked, lowering his voice. “Yes, sir. We’ve been out with the Search,” Ramón said. “Join me.” Richardson pointed to the empty chairs at the table. “How did it go?” “We made no contact with MAD, sir,” Ramón said. “But the Search is still combing the area.” Richardson shook his head. “Damn near impossible with a submerged sub at night, isn't it, boys? The U-Boat’s magnetic field falls off exponentially the deeper it dives. And, of course, you’ve always got echoes from the ocean floor.” He leaned back in his chair. “Chin up, lads. You’ll catch up with Jerry the next time out.” _________________________________________
I'm not familiar with the term "The Search", is this a co-ordinated search by ships and aircraft, flying regular patrols over several months or years? The fluorescent screen quote is right in so far as the main search tool was radar and presumably the MAD searches would only be made once radar had a target. "Sea clutter" - isn't the loss of a target when very close to the aircraft more likely due to the switching time between transmit and receive of a radar pulse? Sea clutter would get worse the lower the plane went but once the target echo merges into the transmit pulse on the screen then the echo would be lost or greatly reduced as the radar receiver is jammed by the transmission for a few microseconds. Radar isn't my field but I know that the switching time and pulse length of a radar were major technical issues to developers. Yes, the MAD printout does have an ECG-like shape, although the shape would vary with height,speed and direction, also size of target and depth. Liked the comment about the "Hooligan Navy", having read Hemingway's factual and fictional accounts of U-Boat hunting off Cuba. He mentions a blimp being shot down by a U-Boat in "Islands in the Stream" and probably based that on a real action. Robin Bird mentioned that MAD wasn't used by the UK forces for various reasons but one that occured to me was that ASW air patrols in UK waters like the northern approaches to the Irish Sea would find MAD very unreliable due to geological conditions. Speaking again from marine experience, there are several areas where strongly-magnetic rock formations would give massive false readings. I don't think this would be an issue in the Cuban/East Coast of US area of operations.
The Royal Air Force and USA did adopt MAD but later in the war operating from Gibraltar. The first notable MAD success was U-761 which attempted to pass through the Straits of Gibraltar on February 24, 1944. It was located by MAD and the kill was shared by US and British Catalinas and the Royal Navy.
Thanks, guys. The "SEARCH" was the term used for: 2d SEARCH ATTACK LINEAGE. Constituted 2nd Sea-Search Attack Squadron (Medium) on 8 Jun 1942. Activated on 17 Jun 1942. Re-designated: 2d Sea-Search Attack Squadron (Heavy) on 24 Jun 1943; 2d Search Attack Squadron (Heavy) on 22 Nov 1943. Disbanded on 10 Apr 1944. ASSIGNMENTS. 1st Sea-Search Attack Group (later Sea-Search Attack Unit; Search Attack Group), 17 Jun 1942 -10 Apr 1944. STATIONS. Langley Field, Va, 17 Jun 1942-10 Apr 1944 (operated from Key West, Fla, 17-23 Aug 1942, and Edinburgh Field, Trinidad, 20 Sep-21 Oct 1942). AIRCRAFT. B-25, 1942; B-18, 1942- 1943; B-24, 1943-1944. OPERATIONS. Tested electronic equipment and trained crews for its use in antisubmarine operations; antisubmarine patrols, Jul 1942 until late 1943.
re: "Sea clutter" unwanted echoes from ground, sea, rain, etc. not being the cause of target loss with early radar systems. How should I phrase the suspected cause in the vernacular? (switching time between transmit and receive of a radar pulse)
OK, thanks for the info on SEARCH. I'm a bit restricted as I don't know the type of radar carried by the B-25 but there is a site here that shows the display on the ASB system that was mentioned in Robin Bird's action report. It gives some details of what the crew would see on their radar when it was in action:- HyperWar: Tactical Uses of Radar in Aircraft (RADTWOA) [Part II] The signal at the bottom of the display is a reflection from the ground or sea surface and gives a rough check of height. It seems that my comment about a very close target being masked by the transmission pulse is not applicable to the ASB display shown as that pulse by my understanding would be below the ground signal, and it's not in the photo. The article does say that turning up the system gain would make the display noisy, "grass" is the term used and sea clutter would no doubt be a factor in making "grass", as would heavy rain. "Grass" is a term I've heard used in conjunction with the British Chain Home EW radar, so it was in general use by the Allies. Perhaps you could work the expression into your book by having the crews referring to "grass" as radar interference in general and forget the transmission pulse aspect? Do you know what radar the B-25s used on Search ops? Cheers '610
