Before being awarded a Nobel Prize, Patrick Blackett was a pioneer in the use of extensive data analysis, error bounding, and probability theory rather than anecdote-based tactics, as he devised improved strategies against deadly German submarines.
Part 1 focused on the beginnings of “systems analysis” approach. This part looks at Blackett’s early work with radar station data-reporting and integration, which set the stage for his work on attacking U-boats.
Beginnings of operations research
When World War II broke out, Blackett was first assigned to help exploit the new technology of radar, which was key in Britain’s defense against German aircraft during the “Battle of Britain.” At that time, the magnetron as a radar-signal source was not yet in general use, and radar-set electronics could only land-based due to their larger size and weight as well as operating wavelength (lower frequency, longer wavelength, larger antennas), (Figure 1). Britain built a string of radar stations called the Chain Home (CH) along the coast facing the English Channel. It was here that Blackett first used his combination of analytical, technical, and practical skills.
Unlike later radars, CH aerials (antennas) did not rotate but were fixed installations which could not electronically steer the signal, unlike our modern physically static phased-array radars. A broad beam of radio pulses was transmitted, ‘floodlighting’ a vast area. Chain Home stations were mounted on cliffs and high ground to increase the detection range, which could be up to 320 km (200 miles). The radar operated at was then a very high frequency between 20 and 60 MHz with a corresponding wavelength between 5 and 15 meters, so the resolution was relatively poor. But that’s all the technology they had available, and they made it work.
Blackett was deeply involved in setting up the operation of radar stations, which required significant manpower to coordinate their outgoing pulse signals and return echoes and update the air defense system and aircraft. This had to be done via telephone and paper tabulations, creating what we would now call a dynamic database. He insisted that scientists and engineers had to do more than just devise a new technology and build a few prototypes, then hand it all over to the troops in the field. Instead, they had to get out there, see how it was being used, and even help with developing an operational structure which took advantage of it.
Further, as a physicist, Blackett was driven by data and its credibility (or lack), analysis, and probabilities. In the early days of the radar-based defense of Britain, reports showed that many more German planes were spotted by radar and then downed off the coastline, compared to the results from inland stations. Speculations on the reasons included differences in radar performance over water versus land, ground clutter, interferon from other signals, and more. Blackett tracked back to the source of the numbers, and found that the real source of the difference was reporting: aircraft kills over land could be verified while those over water could not, and so many of the claimed kills were speculative rather than confirmed.
Blackett was a strong proponent of using data and analytics to better exploit the resources you had available, rather than waiting and hoping for some “next big thing” breakthrough technology. He also looked at the data supporting conventional wisdom and offered counterintuitive ways to use resources. For example, a ring of anti-aircraft batteries was deployed around London, and everyone acknowledges that this defense perimeter had many gaps. But Blackett analyzed the placement of these batteries and probabilities of success at shooting down planes, and showed that it would be better to deploy the batteries in fewer stations but with more guns at each. Even though this left larger gaps in the ring, he showed that the likely success ratio would be higher, as the likelihood of actually hitting an aircraft was very low since only crude proximity fuses were in use. Thousands of shells were expended per successful kill.
Part 3 of this article looks at how Blackett tackled a very different type of data associated with a very different problem: effectively attacking U-boats despite very limited resources, even after they had been spotted.
References
- The Noble Prize, “Patrick M.S. Blackett – Facts“
- John Terraine, “The U-Boat Wars: 1916-1945,” G.P. Putnam’s Sons, 1989.
- Stephen Budiansky, “Blackett’s War: The Men Who Defeated the Nazi U-Boats and Brought Science to the Art of Warfare,” Alfred A. Knopf, 2013.
- May Jo Nye, “Blackett: Physics, War, and Politics in the Twentieth Century,” Harvard University Press, 2004.
- Paul M Kennedy, “Engineers of victory: the problem solvers who turned the tide in the Second World War,” Random House, 2013.
- Donald G. F. W.Macintyre, “U-Boat Killer: Fighting the U-Boats in the Battle of the Atlantic,” Rigel Press, 2004.
- Robert Buderi, “The Invention that Changed the World: How a Small Group of Radar Pioneers Won the Second World War and Launched a Technological Revolution,” Simon & Schuster, 1998.
- Royal Air Force Museum, “RADAR – The Battle Winner?”
- We Are the Mighty, “The mathematician who saved hundreds of flight crews”
- Medium, “Abraham Wald and the Missing Bullet Holes” (an excerpt from “How Not To Be Wrong” by Jordan Ellenberg)
- American Mathematical Society, “The Legend of Abraham Wald”