Simanaitis Says

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I WAS researching the aircraft of Sir Winston Churchill (a tale that’ll appear anon) when I encountered the story of a proposed World War II aircraft carrier made of ice. An eccentric Englishman came up with the idea, Churchill and his Chief of Combined Operations Lord Mountbatten supported it. Though never completed, Project Habakkuk offers great tales.


An artist’s conception of Project Habakkuk.

Geoffrey Pyke, 1893 – 1948, was an English journalist (escaping from German interment during World War I), educator (co-founding the radically progressive Malting House Garden School), spy (against the Nazis in WWII) and inventor.


Pyke’s prototype screw-propelled snow vehicle.

Pyke’s inventions were typically unorthodox, for instance, a screw-propelled snow vehicle. However, his grandest scheme grew from a practical one, investigating a means of deicing ships traveling in Arctic waters. This work led to his devising pykrete, a frozen composite of 14-percent wood pulp and 86-percent ice, and proposing its use in an unsinkable aircraft carrier, the Habakkuk.


The proposed HMS Habakkuk, a conventional battleship and aircraft carrier putting its size in perspective.

The name Habakkuk (misspelled Habbakuk in coded documents of the time) comes from the Book of Habakkuk, the eighth book of the 12 minor prophets of the Hebrew Bible. (Pyke was raised an Orthodox Jew.) The relevant verse, Habakkuk 1:5, in the New International Version is “Look at the nations and watch—and be utterly amazed. For I am going to do something in your days that you would not believe, even if you are told.”

Indeed, the Habakkuk would have been amazing—and huge, with a flight deck 2000 ft. in length. (The world’s largest carriers, the U.S. Nimitz-class, are 1040 ft. long.) With a 7000-mile range, its mission was seen as patrolling the North Atlantic, out of operational range of typical fighter aircraft of the era.


An earlier proposal from a German scientist. Image from Popular Science, September 1932.

Others, including German scientist A. Gerke, had envisioned mid-ocean ice islands as stations for aircraft. Gerke’s proposal would have been completely ice-based, with a refrigeration plant maintaining its frozen condition.

Pyke’s proposal generated the interest of wartime Prime Minister Winston Churchill and his Chief of Combined Operations Lord Mountbatten. A large-scale (60-ft.) model was built in 1943 at Patricia Lake in Canada’s Jasper National Park. The work was done by conscientious objectors who performed their tasks in lieu of military service. They were never told what they were building.

There’s a pair of stories about pykrete and its demonstrations to the military. At the 1943 First Quebec Conference, codenamed Quadrant, Mountbatten touted the potential of Project Habakkuk to allied admirals and generals by firing his service pistol into two blocks, one of ice, the other of pykrete.

The first bullet shattered and splintered the ice. The second one ricocheted off the pykrete, grazed U.S. Admiral Ernest King’s leg and lodged in the wall. Sir Alan Brooke, Chief of Imperial General Staff, reported that “the bullet rebounded out of the block and buzzed round our legs like an angry bee.”


A sample of pykrete, 2 in. thick. The lower mark was caused by a ricocheting round of a 7.62 x 39 mm rifle fired at 15 ft. The upper penetration required seven more rounds. Image from CyranoDeWikipedia.

A similar account is told in I Wish I’d Made You Angry Earlier: Essays on Science, Scientists, and Humanity (Science & Society), by Austrian-born Nobel-Prize-winning British scientist Max Perutz. He had performed research on Pyke’s composite in a secret location beneath London’s Smithfield Meat Market, in a refrigerated meat locker behind a protective screen of frozen animal carcasses.

In his memoirs, Perutz reports a similar comparison test performed by a naval officer. Again, the ice sample shattered and the pykrete resisted damage. This time, though, the ricochet hit Sir Alan Brooke in the shoulder. He was reported unhurt.

There were several Habakkuk options proposed in August 1943. However, Mountbatten lost interest and the project lost wartime priority. Preutz had pointed out one shortcoming: Ice displays a phenomenon called plastic flow, which would have caused a pykrete ship to sag unless kept cooled to 3 degrees Fahrenheit or less. Necessary insulation, ducting and refrigeration would have been complicated and costly.

I suspect too Sir Alan was getting tired of ricochets. ds

© Dennis Simanaitis,, 2015


  1. Alex Law
    April 24, 2015

    One of my favorite weird stories of WWII well told, and how typical of Lord Louis not to think of the ricochet.

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