On the first day of 1942, Gilbert Roberts, a 41-year-old retired British naval officer turned game designer, arrived at Derby House, in Liverpool, for his inaugural meeting with his new boss, Sir Percy Noble.

Gilbert Roberts

The admiral was greying but still youthful, and wore his authority with, as one observer put it, “naturalness.” That day, however, Noble was in a hostile mood.

Participants looking through “peep holes” which gave a realisitic view of what a ship would see.

“I thought the Admiralty were sending me a captain,” he said. Noble explained that he had been instructed to give Roberts the entire top floor of Derby House, comprising eight rooms. There, using wargames, Roberts and his team of Wrens, young members of the Women’s Royal Naval Service, were to get to work on the problem of the U-boats which had, for the past three years, sunk millions of tons of essential food and fuel making its way from the east coast of America via merchant ships.

Wrens plotting the convoy and U-Boat manoeuvrers.

The U-boats, it seemed, had developed an effective tactic that had, to date, evaded the Allied navy, tasked with repelling their attacks. Roberts and the Wrens planned to use wargames to identify this tactic.

Noble – 52 with a headful of hair and a trim waistline — was well liked and respected by his staff, whose opinions he would often seek regardless of their rank or seniority. Still, he couldn’t quite mask his scepticism toward Roberts’ enterprise.

Simon Parkin reveals how a group of young women neutralised German U-boat attacks during the battle of the Atlantic – by playing a game with chalk, canvas and string.

The faceless exterior of Derby House today belies its former importance: within its reinforced core sat the command centre from which Britain’s war against the U-boats in the Atlantic was orchestrated.

The Battle of the Atlantic Command Center

One of the first scenarios that Roberts investigated using his new wargame was the battle of Convoy HG 76. This was a multi-day contest involving 32 merchant ships, 24 escorts and 12 U-boats. It was considered a great Allied victory because five U-boats were sank (though the Allies only knew of three at the time) and 30 merchant ships made it home safely. Assisted by WRENs Jean Laidlaw and Janet Okell, they replayed the historical situation hoping to understand Allied commander Captain Frederick John “Johnnie” Walker’s anti-submarine maneuver ‘Buttercup’.

The Buttercup maneuver involved, “on the order Buttercup… all of the escort ships would turn outward from the convoy. They would accelerate to full speed while letting loose star shells. If a U-boat was sighted, Walker would then mount a dogged pursuit, often ordering up to six of the nine ships in his [escort] group to stay with the vessel until it was destroyed.

What confused Roberts and the WRENS was that the Allied merchant Annavore was torpedoed while in the center of the convoy. As he and the WRENs replayed the scenario they could not duplicate reality unless the U-boat had entered the columns of the convoy from behind. And it must have done so on the surface, where it was able to travel at a faster speed than the ships. By approaching from astern, where the lookouts rarely checked, the U-boat would be able to slip inside the convoy undetected, fire at close range, then submerge in order to get away.

Using the scenario of when the escorts actually sank a U-boat using the Buttercup manoeuvrer it was determined that they had succeeded by only accidentally hitting a U-boat that was joining the attack on the convoy and not the actual U-boat who had made the attack that they were pursuing.

In other words, Walker’s Buttercup manoeuvrer was, in fact, the opposite of what was required.

The ‘Raspberry Manoeuvrer’, created from numerous runs of ‘The Game’ was determined to be an effective anti-submarine tactic. Here it is drawn by Admiral Usborne, and taken from the book. This new manoeuvrer was called “Raspberry,” by Wren Ladlaw as a ‘raspberry‘ to Hitler.

U-boat losses quadrupled almost immediately. As you can see from the above drawing, upon discovery of a U-boat or a torpedo hit, the escorts draw closer to the convoy, not the opposite as in Walker’s Buttercup manoeuvrer. When Roberts and the WRENs ran a scenario for commander Noble and his staff, they were so impressed that he immediately sent a message to Churchill, “The first investigations have shown a cardinal error in anti-U-boat tactics. A new, immediate and concerted counter-attack will be signalled to the fleet within twenty-four hours.”

This was of course not the sole reason for the drastic turn around as advances in technology also played a huge part. It does show, however, how our hobby is an excellent tool, used with the appropriate knowledge of game theory, to aid essential learning. Something which I have been trying to introduce into my profession for decades without much success!

An excellent book that I almost completed in one sitting. The history was something I knew nothing about and no doubt it is the best book I have read in a long time. If you don’t have it buy it.

I received mine in 36 hours from Amazon.

PS Thanks to Dr. Wayne J. Cosshall CEO Techno Magickal Pty. Ltd., and uber Battletech geek from Axes and Ales wargaming club who put me on to this one.