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Johnny Walker Bomb


Well-Known Member
Ordnance approved
Who has technical information about the (500 lb.) Johnny Walker Bomb.

I have the info from the book "Bombs Gone, the development and use of British air-dropped weapons from 1912 to the present day". By W/C John A. MacBean and Maj. Arthur S. Hogben.

These underwater "walking" bombs/mines has been used against the German Battleship Tirpitz on 15 september 1944.


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I have quite a bit of info on the JW bomb, I just can't find it at the moment! Attached is a photo of one. Where was your photograph taken?




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JW Bomb

You will know from Arthur's book that MD1 produced the JW Bomb (in two marks). MD1 was headed up by a Royal Engineer officer Millis Jefferis (MJ). Attached is one of his sketches for the operation of the Oscilating Mine known as Johny Walker.

Plumbing rather than ordnance!


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Very good Photo and sketch guys.

My photo is taken in the Armed Forces Museum (Forsvarsmuseet) at Oslo, Norway.
Parts of these bomb have been found by Norwegian EOD on the mountain slopes of the Kfjord.

Some info says that the ordnance that was used was named “400lb. JW Mk II Mine”. Is this correct, because other sources say 500 lb. And what was the official name?
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The full description in the handbook is;

"Bomb, H.E., Aircraft, J.W., 400lb. Mk.I"
or short "J.W. Bomb"

Although it weighed in at about 400lb the filling was 90lb Torpex.

Do you know if there is a fuze with the specimen that has been recovered?


Tim G.

Thanks for the info.

I do not know if they have recovered the fuze.

What is the title of the Handbook you mentioned?

Greetings - Antoon

"J.W. Bomb and Components - Advance Instructions for use"


I have tried to PM you, but there is a log-jam in your box! I have been warned that mine is about to overflow, too! Regarding Antoon, I have been in contact with the Norwegian EOD some years ago, and was told that the bomb was nearly intact, and the fuze parts had been carefully taken apart and mounted on a display board in a small village museum near the site. Perhaps it has now been moved to the Armed Forces Museum? It seems damage occasioned by falling through trees had prevented it destroying itself-it was still hanging from a tree when a hunter had found it, and was in much better condition than the other two specimens shown in the books mentioned!


JW 3 (1).jpg

A few details about its properties:
At the entry in water, the parachute was discarded to drop and the bom,b sunk to a depth of 17 meters, before rising to just below the surface. If it hit something on the way it would would explode - if not, it would sink again to a depth to17 meters and rise up again, about 10 meters from the last point.
This was possible due to compressed air being discharged from a container in the nose portion into a chamber in the aft portion. The bomb could do up to 100 such cycles. The speed of each cycke could be set to between 1 and 3 minutes, so that the bomb could actually seek a target during a period of 1.5 to 5 hours.
If within that time it had not hit a target, after the last cycle it would sunk to the bottom and destroy itselself.

Can someone add the dimensions (Length / diameter) of the JW bomb?
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You might like to see the sketch of its operation done by Millis Jefferis and the drawing office version. The JW Mk II was about 6 feet long.

JW Operation Sketch by MJ.jpg

SK11426 JW Operation Dwg (4-7-42) cropped2.jpg
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The fuze, which incorporated a 'self destruct' function was plumbed into the gas circuit. When the gas supply was exhausted or tampered with, the self destruct function would operate. However, it was envisaged that a bomb with an all but exhausted gas supply would sink to the bottom but any attempt to bring it to shore would result in the fuze operating.


P.S. I'll try and calculate the dimensions for you.

View attachment anotate22.pdfView attachment jw.pdfView attachment jwiso.pdf
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I have just visited the Tirpitz Museum at Kåfjord outside the city of Alta in Norway (http://tirpitz-museum.no). They have a Johnny Walker on display, as well as lots of photos and artifacts. I also managed to visit the Norwegian Home Front Museum(http://forsvaretsmuseer.no/Hjemmefrontmuseet). The museum is within the Akershus Fortress in Oslo. They have the nose of a Tall Boy that was used on the attack on the Tirpitz. Both museums were well worth the visits.

maybe it was full of whiskey!

I understand (from Macrae's book and from talks with Gordon Rodgers) that it got its name one evening in a pub in or around Whitchurch where they presumably found a supply of the whiskey so named.
Sounds good. Incidentally the Johnny Walker bombs were tested at RAF Helensburgh by the Marine Aircraft Experimental Establishment. The aircraft used was Sunderland DV967 G (Guard for all times). I have the logged details for these JW trials and further research into Sunderland DV967 has just put me on the tail of the infamous U Boat U-564. That is because DV967 was also used at Helensburgh for tail parachute trials to aid dive attacks on submarines. DV967 then joined 228 Squadron when it came across a group of submarines and singled out U-564. Flying Officer L.B. Lee swooped and straddled U-564 with depth charges. U-564 was badly damaged but AA fire ripped the Sunderland to shreds. It crashed into the sea killing the crew. U-564 was fatefully damaged and was sunk next day by another aircraft. I wonder if DV967 was still fitted with its tail parachute when it dived on U-564? We will probably never know.
robin is researching the history of MAEE RAF Helensburgh where his late father served.
Here are some photos I took at the norwegian naval museum in Horten a few weeks back:


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