Tallboy bomb
Overview
 
The Tallboy or Bomb, Medium Capacity, 12,000 lb, was an earthquake bomb developed by the British aeronautical engineer Barnes Wallis
Barnes Wallis
Sir Barnes Neville Wallis, CBE FRS, RDI, FRAeS , was an English scientist, engineer and inventor. He is best known for inventing the bouncing bomb used by the RAF in Operation Chastise to attack the dams of the Ruhr Valley during World War II...

 and deployed by the RAF
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 in 1944. It weighed five ton
Long ton
Long ton is the name for the unit called the "ton" in the avoirdupois or Imperial system of measurements, as used in the United Kingdom and several other Commonwealth countries. It has been mostly replaced by the tonne, and in the United States by the short ton...

s and, carried by the Avro Lancaster
Avro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...

, was effective against hardened structures against which earlier, smaller bombs had proven ineffective.
Wallis presented his ideas for a 10 ton bomb in his 1941 paper A Note on a Method of Attacking the Axis Powers, which showed that a very large bomb exploding deep underground next to a target would transmit the shock into the foundations of the target, particularly since shock waves are transmitted through the ground more strongly than through air.

Wallis designed the "Victory Bomber
Victory Bomber
The British "Victory Bomber" was a Second World War design by Barnes Wallis at Vickers-Armstrongs at Brooklands for a bomber to carry his projected "earthquake bomb" to strategic targets in Germany.-Background:...

" of 50 tons, which would fly at 320 mi/h at 45000 feet (13,716 m) to carry the heavy bomb over 4000 miles (6,437.4 km), but the Air Ministry were against a single-bomb aircraft and the idea was not pursued beyond 1942.

Following Wallis's 1942 paper Spherical Bomb — Surface Torpedo and the design of the "bouncing bomb
Bouncing bomb
A bouncing bomb is a bomb designed specifically to bounce to a target across water in a calculated manner, in order to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined...

" for the Dam Busters
No. 617 Squadron RAF
No. 617 Squadron is a Royal Air Force aircraft squadron based at RAF Lossiemouth in Scotland. It currently operates the Tornado GR4 in the ground attack and reconnaissance role...

 of Operation Chastise
Operation Chastise
Operation Chastise was an attack on German dams carried out on 16–17 May 1943 by Royal Air Force No. 617 Squadron, subsequently known as the "Dambusters", using a specially developed "bouncing bomb" invented and developed by Barnes Wallis...

, the design and production of Tallboy was done without a contract on the initiative of the Ministry.
Encyclopedia
The Tallboy or Bomb, Medium Capacity, 12,000 lb, was an earthquake bomb developed by the British aeronautical engineer Barnes Wallis
Barnes Wallis
Sir Barnes Neville Wallis, CBE FRS, RDI, FRAeS , was an English scientist, engineer and inventor. He is best known for inventing the bouncing bomb used by the RAF in Operation Chastise to attack the dams of the Ruhr Valley during World War II...

 and deployed by the RAF
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 in 1944. It weighed five ton
Long ton
Long ton is the name for the unit called the "ton" in the avoirdupois or Imperial system of measurements, as used in the United Kingdom and several other Commonwealth countries. It has been mostly replaced by the tonne, and in the United States by the short ton...

s and, carried by the Avro Lancaster
Avro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...

, was effective against hardened structures against which earlier, smaller bombs had proven ineffective.

History

Wallis presented his ideas for a 10 ton bomb in his 1941 paper A Note on a Method of Attacking the Axis Powers, which showed that a very large bomb exploding deep underground next to a target would transmit the shock into the foundations of the target, particularly since shock waves are transmitted through the ground more strongly than through air.

Wallis designed the "Victory Bomber
Victory Bomber
The British "Victory Bomber" was a Second World War design by Barnes Wallis at Vickers-Armstrongs at Brooklands for a bomber to carry his projected "earthquake bomb" to strategic targets in Germany.-Background:...

" of 50 tons, which would fly at 320 mi/h at 45000 feet (13,716 m) to carry the heavy bomb over 4000 miles (6,437.4 km), but the Air Ministry were against a single-bomb aircraft and the idea was not pursued beyond 1942.

Following Wallis's 1942 paper Spherical Bomb — Surface Torpedo and the design of the "bouncing bomb
Bouncing bomb
A bouncing bomb is a bomb designed specifically to bounce to a target across water in a calculated manner, in order to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined...

" for the Dam Busters
No. 617 Squadron RAF
No. 617 Squadron is a Royal Air Force aircraft squadron based at RAF Lossiemouth in Scotland. It currently operates the Tornado GR4 in the ground attack and reconnaissance role...

 of Operation Chastise
Operation Chastise
Operation Chastise was an attack on German dams carried out on 16–17 May 1943 by Royal Air Force No. 617 Squadron, subsequently known as the "Dambusters", using a specially developed "bouncing bomb" invented and developed by Barnes Wallis...

, the design and production of Tallboy was done without a contract on the initiative of the Ministry. As such, the RAF were using bombs they had not bought and that were still the property of the manufacturers, Vickers
Vickers
Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

. This situation was normalised once their capabilities were recognised.

Accomplishments of the Tallboy included: 24 June 1944, Operation Crossbow
Operation Crossbow
Crossbow was the code name of the World War II campaign of Anglo-American "operations against all phases of the German long-range weapons programme—operations against research and development of the weapons, their manufacture, transportation and their launching sites, and against missiles in flight"...

 attack on La Coupole
La Coupole
La Coupole , codenamed Bauvorhaben 21 , Schotterwerk Nordwest or Wizernes, is a Second World War bunker complex built by the forces of Nazi Germany between 1943 and 1944 to serve as a launch base for V-2 rockets against London and southern England...

 (along with Grand Slams), which undermined the foundations of this V2 assembly bunker and a Tallboy attack on the Saumur tunnel
Saumur
Saumur is a commune in the Maine-et-Loire department in western France.The historic town is located between the Loire and Thouet rivers, and is surrounded by the vineyards of Saumur itself, Chinon, Bourgueil, Coteaux du Layon, etc...

 on 8-9 June 1944, when bombs passed straight through the hill and exploded inside the tunnel 60 feet (18.3 m) below the surface.

The last of the Kriegsmarines Bismarck-class battleships, the Tirpitz
German battleship Tirpitz
Tirpitz was the second of two s built for the German Kriegsmarine during World War II. Named after Grand Admiral Alfred von Tirpitz, the architect of the Imperial Navy, the ship was laid down at the Kriegsmarinewerft in Wilhelmshaven in November 1936 and launched two and a half years later in April...

, was sunk by an air attack using Tallboys.

Design

Most large Allied World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 aircraft bombs had very thin skins to maximize the weight of explosive a bomber could carry—this was an improvement on the early part of the war when the explosive content of British bomb designs was low.

To be able to penetrate the earth (or hardened targets) without breaking apart, the casing of the Tallboy had to be strong. Each was cast in one piece of high tensile steel that would enable it to survive the impact before detonation. At the same time, to achieve the penetration required, Wallis designed the Tallboy to be very aerodynamic
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...

 so that when dropped from a great height it would reach a velocity higher than traditional bomb designs.

In the final design, the tail of the bomb was about half the overall length of the finished weapon—the bomb casing was some 10 feet (3 m) of the overall 21-foot (6 m) length. Initially the bomb had a tendency to tumble, so the tail was modified—the fins were given a slight twist so that the bomb spun as it fell. The gyroscopic effect thus generated stopped the pitching and yawing, improved the aerodynamics and improved accuracy.

When dropped from 20,000 ft (6,100 m) it made a crater 80 feet deep (24 m) and 100 feet (30 m) across and could go through 16 feet (5 m) of concrete.

W. J. Lawrence wrote about the Tallboy bomb in his book, No 5 Bomber Group:

It was an extraordinary weapon, an apparent contradiction in terms, since it had at one and the same time the explosive force of a large high-capacity blast bomb and the penetrating power of an armour-piercing bomb. On the ground it was capable of displacing a million cubic feet (29,000 m³) of earth and made a crater which it would have taken 5,000 tons of earth to fill. It was ballistically perfect and in consequence had a very high terminal velocity, variously estimated at 3,600 and 3700 feet (1,127.8 m) per second (1,100–1,130 m/s or about 2,500 mph / 4,000 km/h), which was, of course, a good deal faster than sound so that, as with the V-2 rocket
V-2 rocket
The V-2 rocket , technical name Aggregat-4 , was a ballistic missile that was developed at the beginning of the Second World War in Germany, specifically targeted at London and later Antwerp. The liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known...

, the noise of its fall would be heard after that of the explosion.


The weight of the Tallboy (approximately 12,000 lb) and the high altitude required of the bombing aircraft meant that the Avro Lancasters used had to be specially adapted. Armour plating and even defensive armament were removed to reduce weight and the bomb-bay doors had to be adapted. Even then the Lancaster was not capable of reaching the bomb's intended dropping height of 40,000 ft (12,200 m) but only around 25,000 (7,700 m).

At the same time No. 617 "Dambusters" Squadron
No. 617 Squadron RAF
No. 617 Squadron is a Royal Air Force aircraft squadron based at RAF Lossiemouth in Scotland. It currently operates the Tornado GR4 in the ground attack and reconnaissance role...

 trained in the use of a special bombsight, the Stabilizing Automatic Bomb Sight
Stabilizing Automatic Bomb Sight
The Stabilized Automatic Bomb Sight was a tachometric bombsight introduced into operational service by the Royal Air Force in 1943 during World War II. Hand-made throughout its lifetime, the SABS was produced in very small numbers and used only in specialist roles...

 (SABS). For accuracy, multiple corrections had to be made for temperature, wind speed, and other factors. It was only effective if the target could be identified and several missions were cancelled or unsuccessful because of difficulty in accurately identifying and marking the targets.

For use on underground targets, the bomb was fitted with three separate inertia pistols (firing mechanisms). These triggered detonation
Detonation
Detonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives, as well as in reactive gases...

 after a pre-set delay, which gave the bomb sufficient time to penetrate the target before exploding. Depending on mission requirements, the time delay could be set to 30 seconds or 30 minutes after impact.

To guarantee detonation, a total of three separate Type 47 long delay fuze
Fuze
Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...

s were fitted inside the rear of the bomb. This dramatically improved reliability of the weapon: even if two of the fuses failed to function, the third would trigger detonation. Despite this elaborate system, at least one Tallboy failed to explode during the second attack on the Sorpe
Sorpe
The Sorpe Dam is a dam near the small town of Sundern in the German district of Hochsauerland in North Rhine-Westphalia.Like the Biggesee, the Möhne Reservoir and the Verse reservoir, the Sorpe's reservoir is one of the major artificial lakes of the Sauerland's Ruhrverband reservoir association...

 dam and was found during repairs in late 1958 when the reservoir was emptied.

Although the bomb was aimed at the target during an operation, and proved capable of penetrating deep into hardened reinforced concrete when it hit, this was not the primary intention of Barnes Wallis's design. The bomb was designed to impact close to the target, slide into the soil or rock beneath or around the target, and then detonate, transferring all of its energy into the structure, or creating a camouflet
Camouflet
A camouflet, in military science, is an artificial cavern created by an explosion. If the explosion reaches the surface then it is called a crater....

 (cavern or crater) into which the target would fall.

This 'earthquake' effect caused more damage than even a direct hit that penetrated the armour of a target, since even a burst inside a bunker would only damage the immediate surroundings, with the blast dissipating rapidly through the air. An earthquake impact, however, shook the whole target, and caused major structural damage to all parts of it, making repair uneconomic. The attack reports below should be considered with this in mind.

The construction of each Tallboy was labour intensive because each was largely hand-made, requiring much manual labour during each separate manufacturing stage. The materials used were costly, with very precise engineering requirements with regard to casting and machining. For example, to increase penetrative power, a large and specially hardened steel plug had to be precisely machined and mated to a recess in the nose of the bomb. The ogive
Ogive
An ogive is the roundly tapered end of a two-dimensional or three-dimensional object.-Applied physical science and engineering:In ballistics or aerodynamics, an ogive is a pointed, curved surface mainly used to form the approximately streamlined nose of a bullet or other projectile.The traditional...

 had to be machined into a perfectly symmetrical shape to ensure optimum aerodynamic performance. This was no easy task when manipulating a bomb casing with the size and weight of a Tallboy.

Similarly, the Torpex
Torpex
Torpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...

 filling was poured into the base of the upturned casing by hand, after melting it in explosives "kettles". The final stage of explosive filling required that a one inch layer of pure TNT be poured over the Torpex filling, followed by sealing the base with a 4 inch layer of woodmeal-wax composite with three cylindrical recesses fitted with the explosive booster
Explosive booster
An explosive booster acts as a bridge between a low energy explosive and a low sensitivity explosive such as TNT. It increases the explosive shockwave from an initiating explosive to the degree sufficient to detonate the secondary charge.Unlike C4 plastic explosive, not all explosives can be...

s and into which (when the bomb was finally armed), a total of three chemical time-fuses were inserted.

Tallboys were not considered expendable, and if not used on a raid were to be brought back to base rather than safely jettison
Jettison
Jettison may refer to:* A verb meaning to throw or eject from a ship, aircraft or vehicle; or discard or abandon; see marine debris* Jettison , a Chicago-based indie record label* Jettison , a punk band from the 1980s...

ed into the sea. The value of the weapon offset the additional risk to the aircrew.

Given their high unit cost, Tallboys were used exclusively against high-value strategic targets that could not be destroyed by other means. When it was found that the Lancaster could be modified to carry a bomb larger than the Tallboy, Wallis produced the even larger Grand Slam bomb
Grand Slam bomb
The Grand Slam was a 22,000 lb earthquake bomb used by RAF Bomber Command against strategic targets during the Second World War.Known officially as the Bomb, Medium Capacity, 22,000 lb, it was a scaled up version of the Tallboy bomb and closer to the original size that the bombs' inventor,...

.

Tallboy operations

June - August 1944

  • Saumur
    Saumur
    Saumur is a commune in the Maine-et-Loire department in western France.The historic town is located between the Loire and Thouet rivers, and is surrounded by the vineyards of Saumur itself, Chinon, Bourgueil, Coteaux du Layon, etc...

     rail tunnel — The sole operational north-south route on the Loire. Nineteen Tallboy-equipped and six conventionally-equipped Lancasters of 617 Squadron attacked on the night of 8/9 June 1944. This was the first use of the Tallboy bomb and the line was destroyed — one Tallboy bored through the hillside and exploded in the tunnel about 60 ft (18 m) below, completely blocking it. No aircraft were lost during the raid.

Operation Crossbow sorties

Operation Crossbow
Operation Crossbow
Crossbow was the code name of the World War II campaign of Anglo-American "operations against all phases of the German long-range weapons programme—operations against research and development of the weapons, their manufacture, transportation and their launching sites, and against missiles in flight"...

 was a set of offensive and defensive measures that were carried out to deal with the threat of the German V-1 flying bomb
V-1 flying bomb
The V-1 flying bomb, also known as the Buzz Bomb or Doodlebug, was an early pulse-jet-powered predecessor of the cruise missile....

 ("buzz bomb" or "doodlebug") and V-2 rocket
V-2 rocket
The V-2 rocket , technical name Aggregat-4 , was a ballistic missile that was developed at the beginning of the Second World War in Germany, specifically targeted at London and later Antwerp. The liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known...

 weaponry. As part of the operation, a number of sorties using Tallboys were deployed by the British to destroy several missile sites.

19 June 1944 - Watten
The nearest Tallboy dropped by 617 Squadron landed 50 yards (46 m) from the target, a heavily fortified V-2 launch site under construction The bunker was rendered useless.


24 June 1944 - Wizernes
La Coupole
La Coupole , codenamed Bauvorhaben 21 , Schotterwerk Nordwest or Wizernes, is a Second World War bunker complex built by the forces of Nazi Germany between 1943 and 1944 to serve as a launch base for V-2 rockets against London and southern England...

The target was a V-2 assembly and launch site linked with the Watten site. Several Tallboy hits undermined the foundations but did not penetrate the dome. The bunker was abandoned.


25 June 1944 - Siracourt V-1 bunker
Lancasters of 617 Squadron scored three direct hits with Tallboys without loss.

4 July 1944 - Saint-Leu-d'Esserent
Saint-Leu-d'Esserent
Saint-Leu-d'Esserent is a town in northern France situated on the banks of the river Oise. It is designated municipally as a commune within the département of Oise. "Saint Leu" is notable for of mushroom caves under the Thiverny plateau.-History:...

617 Squadron used seventeen Lancasters with Tallboys, supported by one Mosquito
De Havilland Mosquito
The de Havilland DH.98 Mosquito was a British multi-role combat aircraft that served during the Second World War and the postwar era. It was known affectionately as the "Mossie" to its crews and was also nicknamed "The Wooden Wonder"...

 and one Mustang, in an attempt to collapse the limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 roof of the caves used as storage depots. Aircraft from No 5 Group followed up with 1000 lb (453.6 kg) bombs.


6 July 1944 - Mimoyecques
Tallboys hit one of the V-3 cannon
V-3 cannon
The V-3 was a German World War II supergun working on the multi-charge principle whereby secondary propellant charges are fired to add velocity to a projectile....

's shafts and blocked galleries with earth and debris


17 July 1944 - Wizernes
Sixteen Lancasters, led by a Mosquito and a Mustang, bombed Wizernes -- three Lancasters managed to drop Tallboys (one caused the dome to shift out of alignment, two others blocked the entrance.


27 July 1944 - Watten
One Tallboy hit the target but did not penetrate the structure.


31 July 1944 - Rilly La Montagne
Both ends of the railway tunnel were collapsed by Tallboys dropped by 617 Squadron. William Reid
William Reid (VC)
William Reid VC was a Scottish recipient of the Victoria Cross, the highest and most prestigious award for gallantry in the face of the enemy that can be awarded to British and Commonwealth forces...

's Lancaster at 12000 ft (3,657.6 m) was hit by a Tallboy dropped from 18000 ft (5,486.4 m)

Sorties against German dockyards

Shipping in the English Channel and the Atlantic Ocean were threatened by U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

s and E-boats stationed in France. U-boat docks were protected against conventional aerial bombardment by thick concrete roofs.

14 June 1944 - Le Havre
Le Havre
Le Havre is a city in the Seine-Maritime department of the Haute-Normandie region in France. It is situated in north-western France, on the right bank of the mouth of the river Seine on the English Channel. Le Havre is the most populous commune in the Haute-Normandie region, although the total...

Part of the first massive RAF daylight raid since the end of May 1943, two waves attacked E-boat facilities at Le Havre: No 1 Group first, No 3 Group second. Just before the first wave, 22 Lancasters of 617 Squadron and 3 Mosquito marker aircraft attacked, several hits were scored on the pens, one bomb penetrated the roof.


15 June 1944 - Boulogne harbour
Boulogne-sur-Mer
-Road:* Metropolitan bus services are operated by the TCRB* Coach services to Calais and Dunkerque* A16 motorway-Rail:* The main railway station is Gare de Boulogne-Ville and located in the south of the city....

297 aircraft - 155 Lancasters, 130 Halifax
Handley Page Halifax
The Handley Page Halifax was one of the British front-line, four-engined heavy bombers of the Royal Air Force during the Second World War. A contemporary of the famous Avro Lancaster, the Halifax remained in service until the end of the war, performing a variety of duties in addition to bombing...

es, 12 Mosquitos - of Nos 1, 4, 5, 6 and 8 Groups attacked Boulogne harbour. One Halifax was lost. A French report described the great destruction as the worst raid on Boulogne.


5 August 1944 - Brest
Brest, France
Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon...

15 Lancasters of 617 Squadron attacked the U-boat pens at Brest and scored six direct hits with Tallboys penetrating the concrete roofs. One Lancaster was shot down by flak. Subsequent attempts to reinforce other sites with even thicker concrete diverted resources from other projects.


6 August 1944 - Keroman
Flight Lieutenant Thomas Clifford Iveson dropped one Tallboy.


7 August 1944 - Lorient
Lorient
Lorient, or L'Orient, is a commune and a seaport in the Morbihan department in Brittany in north-western France.-History:At the beginning of the 17th century, merchants who were trading with India had established warehouses in Port-Louis...

The planned Tallboy mission against the U-boat pens was cancelled


8 August 1944 - La Pallice
Flight Lieutenant Thomas Clifford Iveson dropped one Tallboy.


28 August 1944 - IJmuiden
Flight Lieutenant Thomas Clifford Iveson dropped one Tallboy.

September - November 1944

  • Dortmund-Ems Canal
    Dortmund-Ems Canal
    The Dortmund–Ems Canal is a 269 km long canal in Germany between the inland port of the city of Dortmund and the sea port of Emden. The artificial southern part of the canal ends after 215 km at the lock of Herbrum near Meppen. From there, the route goes over a length of 45 km over...

     near Ladbergen
    Ladbergen
    Ladbergen is a municipality in the district of Steinfurt, in North Rhine-Westphalia, Germany. It is situated near the Dortmund-Ems Canal, approximately 25 km south-west of Osnabrück and 20 km north-east of Münster.-Geography:...

    , north of Münster
    Münster
    Münster is an independent city in North Rhine-Westphalia, Germany. It is located in the northern part of the state and is considered to be the cultural centre of the Westphalia region. It is also capital of the local government region Münsterland...

    617 Squadron scored six direct hits with Tallboys on the night of 23/24 September 1944.
  • Kembs Dam north of Basle — The dam waters could have been kept in reserve to flood the area of a US advance. On 7 October 1944, the Dambusters destroyed the lock gates with Tallboys dropped at low level, releasing the stored water.
  • Sorpe
    Sorpe
    The Sorpe Dam is a dam near the small town of Sundern in the German district of Hochsauerland in North Rhine-Westphalia.Like the Biggesee, the Möhne Reservoir and the Verse reservoir, the Sorpe's reservoir is one of the major artificial lakes of the Sauerland's Ruhrverband reservoir association...

     dam — This target of the original Dambusters raid survived a second attack by 9 Squadron on 15 October 1944 (617 Squadron did not participate in this raid). The Tallboy bombs were seen to hit the dam but did not breach it.

Bombing sorties against Tirpitz

The German battleship Tirpitz
German battleship Tirpitz
Tirpitz was the second of two s built for the German Kriegsmarine during World War II. Named after Grand Admiral Alfred von Tirpitz, the architect of the Imperial Navy, the ship was laid down at the Kriegsmarinewerft in Wilhelmshaven in November 1936 and launched two and a half years later in April...

 was a threat against convoys sailing to and from the Soviet Union.

Operation Paravane
Operation Paravane
Operation Paravane was the attack carried out by RAF Bomber Command on September 15, 1944 against the German battleship Tirpitz at harbour in the far north of Norway. The Tirpitz was a major threat to the convoys supplying the Soviet Union. Flying via a Soviet airfield, two squadrons attacked...

, 15 September 1944
One Tallboy hit near the bow of the Tirpitz and caused considerable damage. The shock-wave from the hit damaged the battleship's engines, the Germans converted the ship for use as a semi-static heavy artillery battery.


Operation Obviate
Operation Obviate
Operation Obviate was the RAF Bomber Command attack on the German battleship Tirpitz at Tromsø on 29 October 1944. The attack was foiled by cloud covering the ship at the last minute, and the bombs that were dropped caused only minor damage...

, 29 October 1944
No direct hits were scored but one near miss bent a propeller shaft.


Operation Catechism
Operation Catechism
Operation Catechism was the last of nine attempts to sink or sabotage the Kriegsmarine battleship Tirpitz during World War II. On November 12, 1944, the RAF Bomber Command dispatched 30 Avro Lancaster heavy bombers from No. 9 Squadron RAF and No. 617 Squadron RAF Operation Catechism was the last of...

, 12 November 1944
In the final operation the Tirpitz was sunk when two Tallboys hit and four others near-missed her. The battleship rolled over and capsized in shallow water.

December 1944 - April 1945

Bombing of U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

 pens, December 1944-April 1945
  • IJmuiden, 15 December 1944
Flight Lieutenant Thomas Clifford Iveson dropped one Tallboy.

IJmuiden, 12 January 1945
617 Squadron attacked the U-boat pens with Tallboys, but smoke obscured the results.
  • Bergen
    Bergen
    Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , ....

    , 12 January 1945
32 Lancasters and one Mosquito of Nos 9 and 617 Squadrons attacked U-boat pens and shipping in Bergen harbour. Three Lancasters of 617 Squadron and one from 9 Squadron were lost; the Germans told the local people that 11 bombers had been shot down. A local report said that three Tallboys penetrated the 3½-metre-thick roof of the pens and caused severe damage to workshops, offices and stores inside.
  • IJmuiden & Poortershaven 3 February 1945
36 Lancasters of No 5 Group attacked U-boat pens at IJmuiden (9 Squadron) and Poortershaven (617 Squadron) with Tallboys. Hits were claimed on both targets without loss.
  • Hamburg
    Hamburg
    -History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...

    , 9 April 1945
617 Squadron attacked with Tallboys and Grand Slams. Some of the bombs hit their target and no aircraft were lost.
  • Heligoland
    Heligoland
    Heligoland is a small German archipelago in the North Sea.Formerly Danish and British possessions, the islands are located in the Heligoland Bight in the south-eastern corner of the North Sea...

    , 18 April 1945
969 aircraft - 617 Lancasters, 332 Halifaxes and 20 Mosquitos of all groups bombed the naval base, airfield and town "almost into crater-pitted moonscape
Moonscape
A moonscape is an area or vista of the lunar landscape , or a visual representation of this, such as in a painting. The term "moonscape" is also sometimes used metaphorically for an area devastated or flattened by war, often by shelling....

s". Three Halifaxes were lost; the islands were evacuated the following night.
  • Heligoland, 19 April. 36 Lancasters used Tallboy bombs against coastal positions


The Urft Dam, (30 miles south west of Cologne
Cologne
Cologne is Germany's fourth-largest city , and is the largest city both in the Germany Federal State of North Rhine-Westphalia and within the Rhine-Ruhr Metropolitan Area, one of the major European metropolitan areas with more than ten million inhabitants.Cologne is located on both sides of the...

) was attacked on 8 December and 11 December 1944 to prevent it being used to flood the area as American troops advanced. The lip of the dam was damaged, but the Germans prevented further damage by lowering the water level.

Politz
Politz
Politz are German names of the places in Czechia: , a town in North Bohemia; now a district of Děčín , a city in north BohemiaOther:*Politz Day School, a private Jewish school in Cherry Hill, New Jersey- See also :* Police* Pollitz...

 was attacked by 617 Squadron on 21 December 1944

The Bielefeld
Bielefeld
Bielefeld is an independent city in the Ostwestfalen-Lippe Region in the north-east of North Rhine-Westphalia, Germany. With a population of 323,000, it is also the most populous city in the Regierungsbezirk Detmold...

 and Arnsberg
Arnsberg
Arnsberg is a town in the Hochsauerland district, in North Rhine-Westphalia, Germany. It is the location of the Regierungsbezirk Arnsberg's administration and one of the three local administration offices of the Hochsauerlandkreis.-Geography:...

 viaducts were attacked by 617 and 9 squadrons with Tallboys and the first Grand Slams on 14 March 1945. The Arnsberg viaduct withstood the attack but 100 m of the Bielefeld viaduct collapsed through the 'earthquake effect' of the Grand Slams and Tallboys. The Arnsberg viaduct was attacked again on 15 March 1945 by 9 Squadron, it did not collapse.

The Pocket battleship Lützow
German pocket battleship Deutschland
Deutschland was the lead ship of her class of heavy cruisers which served with the Kriegsmarine of Nazi Germany during World War II. Ordered by the Weimar government for the Reichsmarine, she was laid down at the Deutsche Werke shipyard in Kiel in February 1929 and completed by April 1933...

 was attacked on 16 April 1945 by 617 Squadron. Despite intense flak, 15 aircraft managed to bomb the target with Tallboys or with 1,000-pounders. One near miss with a Tallboy tore a large hole in the bottom of the Lützow and she settled to the bottom in shallow water. One Lancaster was shot down, the Squadron's last loss of the war.

Hitler's vacation home, Berghof
Berghof (Hitler)
The Berghof was Adolf Hitler's home in the Obersalzberg of the Bavarian Alps near Berchtesgaden, Bavaria, Germany. Other than the Wolfsschanze in East Prussia, Hitler spent more time at the Berghof than anywhere else during World War II. It was also one of the most widely known of Hitler's...

, near Berchtesgaden
Berchtesgaden
Berchtesgaden is a municipality in the German Bavarian Alps. It is located in the south district of Berchtesgadener Land in Bavaria, near the border with Austria, some 30 km south of Salzburg and 180 km southeast of Munich...

 was attacked on 25 April 1945 with a mixed force that included six Lancasters of 617 Squadron dropping their last Tallboys. The bombing appeared to be accurate and effective.

Use by USA

The T10 was an American-made version of the 12,000 lb Tallboy modified to use standard American components. Development was started in late 1944 and plans were made to drop them on the fortified island strongholds of the Pacific to aid in softening their defences before amphibious assaults. None were ever used in combat because the capitulation of Japan following the atomic bombings of Hiroshima and Nagasaki
Atomic bombings of Hiroshima and Nagasaki
During the final stages of World War II in 1945, the United States conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan, the first on August 6, 1945, and the second on August 9, 1945. These two events are the only use of nuclear weapons in war to date.For six months...

 negated their need. Later in the late 1950s the T-10 was re-designated the M-121. Later during the Korean War a number of T-10s were converted to the radio guided Tarzon
ASM-A-1 Tarzon
The ASM-A-1 Tarzon, also known as VB-13, was a guided bomb developed by the United States Army Air Forces during the late 1940s. Mating the guidance system of the earlier Razon radio-controlled weapon with a British Tallboy bomb, the ASM-A-1 saw brief operational service in the Korean War before,...

 bomb and was used to destroy railroad bridges and reservoir dams, being dropped by the B-29 Super Fortress.

After the Korean War ended and the B-29 and B-36 bombers were retired the USAF no longer had an aircraft that could drop the completely assembled M-121 and they were put in storage. Production of the T-10 ended in 1955. The B-36 was the last operational aircraft that could drop a fully assembled Tallboy type bomb in the conventional way. During the Vietnam War, some M-121s, minus their rear streamline shroud and tail fin assembly were shipped to Vietnam for Commando Vault missions where the warhead was dropped by C-130 using radar control. The warhead was mounted on a platform and pulled by a parachute from the rear loading ramp of the C-130. After clearing the aircraft the large extraction chute and pallet were cut away and small triangular chute stabilized the large warhead till impact. A three foot nose probe detonated the bomb at the right stand-off. One of the greatest missions for the last of the World War Two Tallboy designs was the dropping of one on a Commando Vault mission to clear a landing zone for helicopters on a ridge during the famous Battle of Hamburger Hill
Battle of Hamburger Hill
The Battle of Hamburger Hill was a battle of the Vietnam War which was fought by the United States and South Vietnam against North Vietnamese forces from May 10–20, 1969. Although the heavily fortified Hill 937 was of little strategic value, U.S. command ordered its capture by a frontal assault,...

. Dropping from 10,000 feet the bomb hit exactly where it was needed. In reality the Commando Vault missions were more accurate in bomb delivery on target than the more modern B-52s.

Work still progressed on the 43000 lb (19,504.5 kg) T-12 Cloudmaker, which the B36 Peacemaker
Convair B-36
The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force from 1949 to 1959. The B-36 was the largest mass-produced piston engine aircraft ever made. It had the longest wingspan of any combat aircraft ever built , although there have...

 had been redesigned to deploy.

External links

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