British amphibious attack of 28 March 1942
The St Nazaire Raid or Operation Chariot was a British amphibious attack on the heavily defended Normandie dry dock at St Nazaire in German-occupied France during the Second World War. The operation was undertaken by the Royal Navy (RN) and British Commandos under the auspices of Combined Operations Headquarters on 28 March 1942. 
St Nazaire was targeted because the loss of its dry dock would force any large German warship in need of repairs, such as , sister ship of , to return to home waters by running the gauntlet of the Home Fleet of the Royal Navy and other British forces, via the English Channel or the North Sea.
The obsolete destroyer , accompanied by 18 smaller craft, crossed the English Channel to the Atlantic coast of France and rammed into the Normandie dry dock south gate. The ship had been packed with delayed-action explosives, well hidden within a steel and concrete case, that detonated later that day, putting the dock out of service until 1948.
A force of commandos landed to destroy machinery and other structures. German gunfire sank, set ablaze, or immobilized virtually all the small craft intended to transport the commandos back to England. The commandos fought their way through the town to escape overland but many surrendered when they ran out of ammunition or were surrounded by the Wehrmacht defending Saint-Nazaire.
Of the 612 men who undertook the raid, 228 returned to Britain, 169 were killed and 215 became prisoners of war. German casualties included over 360 dead, some of whom were killed after the raid when "Campbeltown" exploded. To recognise their bravery, 89 members of the raiding party were awarded decorations, including five Victoria Crosses. After the war, St Nazaire was one of 38 battle honours awarded to the commandos. The operation has been called "the greatest raid of all" in British military circles.
Background.
St Nazaire is on the north bank of the Loire, from the nearest British port. In 1942, it had a population of 50,000. The St Nazaire port has an outer harbour known as the Avant Port, formed by two piers jutting out into the Atlantic Ocean. This leads to two lock gates before the Bassin de St Nazaire. These gates control the water level in the basin so that it is not affected by the tide.
Beyond the basin is the larger inner dock called the Bassin de Penhoët, which can accommodate ships up to 10,000 tons. There is also an old entrance to the Bassin de St Nazaire midway along the Bassin de St Nazaire. Immediately upstream of this lies the Normandie dry dock, between the Bassin de St Nazaire and the Loire, with its southern end giving on to the Loire and the northern end facing into the Bassin de Penhoët. Built to house the ocean liner , this dock was the largest dry dock in the world when it was completed in 1932. The "Old Mole" jetty juts into the Loire halfway between the southern pier of the Avant Port and the old entrance into the basin.
On 24 May 1941, the Battle of the Denmark Strait was fought between the German ships and and the British ships and . "Hood" exploded and sank; the damaged "Prince of Wales" was forced to retire. "Bismarck", also damaged, ordered her consort to proceed independently while she headed for the French port of St Nazaire, which was the only port on the Atlantic coast with a dry dock able to accommodate a ship of her size. She was intercepted by the British and sunk en route.
Britain's Naval Intelligence Division first proposed a commando raid on the dock in late 1941. When the was declared operational in January 1942, the Royal Navy (RN) and Royal Air Force (RAF) were already drawing up plans to attack her. Planners from Combined Operations Headquarters were looking at potential scenarios if "Tirpitz" escaped the naval blockade and reached the Atlantic. They decided the only port able to accommodate her was St Nazaire, especially if, like "Bismarck", she was damaged en route and needed repairs. They came to the conclusion that if the dock at St Nazaire were unavailable, the Germans were unlikely to risk sending "Tirpitz" into the Atlantic.
Combined Operations examined several options while planning the destruction of the dock. At this stage of the war the British government still tried to avoid civilian casualties. This ruled out a bombing attack by the RAF, which at the time did not possess the accuracy needed to destroy the dock without serious loss of civilian life.
The Special Operations Executive (SOE) were approached to see if its agents could destroy the dock gates. They decided that the mission was beyond their capabilities because the weight of explosives required would have needed too many agents to carry them. The Royal Navy was also unable to mount an operation, as St Nazaire is up the Loire estuary. Any naval ships large enough to cause sufficient damage would be detected well before they were within range.
The planners then examined whether a commando force could accomplish the task. An unusually high spring tide was due in March 1942 which would allow a light ship to pass over the sand banks in the estuary and approach the docks, bypassing the heavily defended dredged channel. In one early plan, the planners designed a raid to approach the docks with only motor launches. John Hughes-Hallett and his colleagues immediately rejected this plan. Their opposition to the plan was strong. They argued, "they'll never reach the shore..." They concluded, "no destroyer, no operation." The approach was also too shallow for an infantry landing ship, but the planners believed if a destroyer could be lightened it might have a draft shallow enough to enable it to get through.
Plan.
The purpose of the raid was to destroy the Normandie dock, the old gates into the Bassin de St Nazaire with the water pumping machinery and other installations and any U-boats or other shipping in the area. The initial Combined Operations plan required one specially lightened destroyer to carry out the raid. It would be packed with explosives and rammed into the dock gates. Commandos on board would then disembark and use demolition charges to destroy nearby dock installations, searchlights and gun emplacements. The destroyer would then be blown up. At the same time the RAF would undertake diversionary air raids in the area.
When the plan was presented to the Admiralty they refused to support it. The certain loss of one or both destroyers to eliminate the dry dock was out of the question. They suggested they could provide an old Free French destroyer, , and a flotilla of small motor launches to transport the commandos and evacuate them afterwards. Approval for the mission, codenamed Operation Chariot, was given on 3 March 1942. Using a French ship would involve using the Free French forces and increase the number of people aware of the raid. Consequently, it was decided the navy would have to provide a ship of their own. The RAF complained that the raid would draw heavily on their resources and the number of aircraft assigned by RAF Bomber Command dwindled during the planning of the raid. British Prime Minister Winston Churchill further complicated matters when he ordered that bombing should only take place if targets were visually identified.
Combined Operations Headquarters worked closely with several intelligence organisations to plan the raid. The Naval Intelligence Division compiled information from a variety of sources. A detailed plan of the town of St Nazaire was provided by the Secret Intelligence Service, and information on the coastal artillery nearby was provided by the War Office's Military Intelligence branch. Intelligence about the dock itself came from pre-war technical journals. The Naval Operational Intelligence Centre selected the route and timing for the raid based on intelligence about the location of minefields and German recognition signals gleaned from Enigma decryptions and knowledge of Luftwaffe patrols compiled by the Air Ministry's Air Intelligence Branch. When all the plans had been pulled together and the timing worked out, the main part of the raid was expected to last no longer than two hours. The commandos and crew from "Campbeltown" were to board the motor launches at the Old Mole jetty and then make their escape.
Composition of the raiding force.
The revised Combined Operations plan required one destroyer to ram the dock gates and a number of smaller craft to transport the commandos. The Royal Navy would therefore provide the largest contingent for the raid, under the overall command of the senior naval officer, Commander Robert Ryder. The ship selected to ram into the dock gates was , commanded by Lieutenant Commander Stephen Halden Beattie. "Campbeltown" was a First World War destroyer and had previously been in the United States Navy. She had come into RN service in 1940 as one of 50 destroyers transferred to the United Kingdom under the destroyers-for-bases deal.
Converting "Campbeltown" for the raid took ten days. She had to be lightened to raise her draught to get over the sand banks in the estuary. This was achieved by completely stripping all her internal compartments. The dockyard removed her three guns, torpedoes and depth charges from the deck and replaced the forward gun with a light quick-firing 12-pounder gun. Eight 20 mm Oerlikons were installed on mountings raised above deck level. The bridge and wheelhouse were given extra armour-plate protection, and two rows of armour were fixed along the sides of the ship to protect the commandos on the open deck.
Two of her four funnels were removed, and the forward two were cut at an angle to resemble those of a German destroyer. The bow was packed with 4.5 tons of high explosives, which were set in concrete. The explosives were the Mark VII depth charge. It was decided that the explosive charge would be timed to detonate after the raiders had left the harbour. To prevent the Germans towing her away, the crew would open the ship's seacocks before abandoning the ship. Should she become disabled or sunk before getting to the dock, four motor launches had been detailed to take off the crew and put the commandos ashore. The charge would be reset to explode after the last boat had left.
Other naval units involved were two s, and , which would accompany the force to and from the French coast and remain out at sea during the raid. A motor gun boat (the Fairmile C type "MGB 314") was the headquarters ship for the raid, with Commander Ryder and the commanding officer of the commandos on board, Lieutenant-Colonel A. C. Newman. A motor torpedo boat (a 70 ft Vosper, "MTB 74"), commanded by Sub-Lieutenant Michael Wynn, had two objectives: If the outer Normandie dock gates were open, she had to torpedo the inner dock gates. If the gates were closed she would instead torpedo the gates at the old entrance into the St Nazaire basin.
Wynn's boat was offered for the raid at the last moment. The MTB consumed a lot of petrol and was capable of only two speeds: a slow 6 knots and a fast 33 knots. The flaw meant the MTB could only progress by leap frogging and waiting. It was clear she would need a tow if taken in that condition. The flawed boat brought disapproval, necessitating last-minute modifications.
To assist in transporting the commandos, 12 Fairmile B Motor Launches (ML) were assigned from the 20th and 28th Motor Launch flotillas. These boats were re-armed with two Oerlikon 20 mm guns mounted forward and aft to complement their twin 0.303-in Lewis guns. At the last minute another four MLs were assigned from the 7th Motor Launch flotilla (see Footnotes for flotilla details). These four boats were also armed with two torpedoes each. Instead of transporting the commandos, these boats were to engage any German shipping found in the estuary. All the MLs had a auxiliary fuel tank fixed to the upper deck to increase their range. The S-class submarine would leave before the rest of the convoy and be in position to act as a navigational beacon to guide the convoy into the Loire estuary.
The man selected to lead the Commando force was Lieutenant Colonel Charles Newman; his No. 2 Commando would provide the largest commandos contingent, 173 men, for the raid. The Special