Raspberry to Banana: How a group of women officers' jugaad changed WW-II

How a key battle was won by by jugaad - not technological superiority

The Second World War (WW-II) led to huge advances in weaponry as well as the development of antibiotics, chemotherapy, radar, sonar, plastics, and other things. But one key battle was won by what we may call “jugaad” rather than technological superiority.

 

This was the long-running Battle of the Atlantic, which lasted from 1939-1945 — the entire length of WW-II. The equation was simple. Britain was deficient in food, oil, and other raw materials, and had to import from the United States. That meant convoys of merchant ships across the Atlantic. German submarines would attack these convoys.

 

German subs would find a convoy, stalk it, and gather “wolfpacks” consisting of many U-boats. Then the packs would launch concerted night attacks, surfacing to use torpedoes on merchantmen at close range and dive away to safety before escorting warships could counterattack.

 

This was effective. Tonnage losses exceeded replacement rates for many months. The Royal Navy (RN) tried increasing the number of escorts per convoy and running smaller convoys. But ships continued to be sunk in huge numbers. Also, smaller convoys meant less tonnage transported, and the RN simply didn’t have enough escorts to support them. 

 

The RN finally evolved some effective tactics.  Patrick Blackett was a former navy officer turned Cambridge don. He won the 1948 Nobel Prize for Physics for his work on the transmutation of elements. But his suggestions relied on elementary mathematics, not nuclear physics.

 

Blackett asked the navy to run much larger convoys without increasing the number of escorts by much. Convoy formations had merchant ships steaming within a (moving) circle, while the perimeter was patrolled by escort warships. The formula for the perimeter of a circle is Pi multiplied by twice the radius, whereas the area of a circle is given by Pi into radius squared. Hence, if the radius is doubled, the circle’s area increases by a factor of four, while the perimeter only doubles.

 

So even if there were twice as many ships per convoy, the perimeter increased much less than the area, and the ratio of escorts to merchantmen could be reduced. This was the point. Blackett also predicted places where attacks were most likely with great accuracy. His suggestions halved the percentage of losses per convoy.

 

One key factor in engagements was time. U-boats had to be close to the surface (and thus vulnerable) in order to fire torpedoes accurately. Ideally, they would surface to travel faster and attack with greater accuracy. But they could only spend limited time “upstairs” before diving to safety. 

 

The second tactic was dreamt up by a bunch of teenaged girls and slashed the time available for U-boats. The navy was short of officers. So, they picked young girls in the WRNS (Women’s Royal Naval Service) with mathematical backgrounds to help war-game the convoy situation. These games turned into lessons in humiliation for naval officers.

 

The “Wrens” were smart and sneaky, and no respecters of protocol. They repeatedly thrashed experienced naval officers in simulated convoy engagements. One of them said it was much easier to fool an Admiral than to sneak an unsuitable boyfriend past her mother.

 

In the navy’s approved convoy-defence protocols, a merchant ship under attack would radio the escort commander, who would then issue defensive orders to all ships. This process took an average of 8–10 minutes.

 

The Wrens junked the protocol. Instead, they suggested that the ship should simply transmit “Raspberry”. Escorts could then immediately launch a counterattack, using starshells for illumination, depth charges, etc, without waiting for formal orders. “Raspberry” took 90 seconds. (As a corollary, if any ship in a convoy spotted a lone sub, it would transmit “Banana”.)

 

When Raspberry went into operation along with Blackett’s suggestions, the tide turned, as the Germans began losing U-boats at an unsustainable rate. Of course, technology played a role as well. By late 1943, the escorts included long-range aircraft. As sonar and radar improved, and depth charges and “hedgehog” mortars became more lethal, U-boats grew increasingly vulnerable. But Blackett’s ideas and Raspberry worked well even during the period of resource crunch.

 

Sadly, it took several months before these suggestions were implemented. Naval officers had to swallow their pride before these ideas were accepted, and thousands of men died before that happened. There’s a lesson here for frugal management theorists.