Rettungsboje, the rescue buoy devised by the Germans in World War II to save downed pilots

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Searching for a castaway lost at sea is an arduous and often frustrating task. Unless the search area can be narrowed down a lot, the task can be prolonged so long that probably when he or she is finally located – if at all – he or she is already dead from hypothermia, dehydration or any other cause. It is worse in wartime because the subject could also be injured. So one can imagine the number of such dramas experienced by the German and British pilots who faced each other in the English Channel during the Second World War, in the context of the so-called Battle of England. So much so that a system was devised to try to alleviate it: the Rettungsboje or Rescue Buoy.

If you make a trip to Scotland and pass through the small town of Irvine, on the west coast of the country, you will not only have the chance to discover an attractive medieval village where writers like Edgar Allan Poe or Robert Burns lived but also to visit the Scottish Maritime Museum, a naval museum (decentralized, because part of the facilities are in the neighboring town of Dumbarton) located in a former shipyard. Most of its collection is of an industrial nature and is therefore made up of port machinery and ships from the 19th and 20th centuries. But there is also a strange vessel that does not go unnoticed.

Several units of Rettungsboje/Image: Luftwaffe-zur-See

This is the ASR-10, acronym and number of the Air-Sea Rescue Float, a rescue buoy developed by British engineers from which sixteen units were built, deployed along the main routes used by the air squadrons that crossed the English Channel to bomb enemy targets on the continent. This type of device was designed so that the downed pilots would find an acceptably comfortable refuge that would allow them to survive until their rescue, hence they had ad hoc equipment such as a first aid kit, drinking water, food, kitchen, stove, clothes and blankets. It also had a radio and a capacity for six people.

The characteristics of the buoys, by adapting old steel hulls from retired boats, allowed them to house half a dozen bunk beds and, therefore, provide their eventual users with some comfort, given the circumstances. The shipwrecked person could climb without difficulty using some stairs or by the stern, when it leaned and presented a grid that allowed to climb. It was this same fusiform physiognomy that led to the reuse of the ASR-10 at the end of the war and its conversion into a yacht; later, the war material began to be revalued as heritage and the ingenuity underwent a restoration for exhibition in the museum, showing its striking alternating yellow and red colours.

The ASR-10 preserved at the Scottish Maritime Museum/Image: Rosser1954 in Wikimedia Commons

However, it was not the English who had the original idea of creating and placing rescue points in the maritime strip that separates their country from the rest of Europe but the Luftwaffe, the air force of the Third Reich. Earlier we outlined the Battle of England, generic name given to the opposition presented by the RAF to the bombing campaign unleashed by German planes. Hitler needed to obtain superiority in the sky in order to protect Operation Sea Lion, that is, the invasion of the British Isles, given the inferiority of the Kriegsmarine with respect to the Royal Navy. The confrontation was fierce, as it lasted longer than expected (four months between July and October 1940) and, consequently, the casualty figures were overwhelming.

Thus, the Luftwaffe lost almost two thousand planes per thousand and a half of the British. That meant hundreds of men from both sides who lost their lives and many others who survived their downing or a forced landing, ending up at sea waiting for a rescue that, as we said before, to its intrinsic difficulty added that derived from operating in a combat zone. Therefore, in September 1940, the RLM (Reichsluftfahrtministerium, Reich Air Ministry) commissioned the T-Amt (Technisches Amt, an area of research and project development) to work on the design of an emergency solution for those pilots and crew members lost but still alive.

Battle of England Operations Area/Image: public Domain in Wikimedia Commons

The T-Amt was directed by Generaloberst Ernst Udet, a former aviation ace of the First World War who, despite detesting his position as merely administrative (which led him to alcoholism and, eventually, suicide), had promoted the technique of dive bombing and the most characteristic aircraft for it, the famous Stuka. On this occasion he fulfilled again and presented what was baptized as Rettungsboje or Rescue Buoy, popularly known as Udet-Boje for obvious reasons. Over the next two months, fifty units were built (later as many would be added) which were distributed throughout the English Channel; two of them were dragged by British ships to study them.

The concept was simpler than what the British would do later and was more in keeping with its name: it lacked a proper helmet and was a floating capsule with a square or hexagonal shape that measured thirteen square meters and had a room four by two high, with capacity for four people. It was topped by a two-meter turret that extended into a mast with white and red light signals (visible from almost a kilometer away), as well as sound (a radio SOS) and smoke.

A sketch of the inside of a Rettungsboje/Image: public Domain in Wikimedia Commons

The castaways who glimpsed among the waves the striking color of the buoy (yellow, like the ASR, but adding emblems of the Red Cross), could swim there, check the direction of the current thanks to a few ribbons of a hundred meters with floats that were attached to the contraption, cling to some handrails to climb and open the access door. Then came the end of their hardships. Inside, they found first aid equipment, two pairs of superimposed bunk beds, dry clothes, a stove, a flare gun, a transmitter, cigarettes, cognac, board games to entertain themselves, tools to plug possible bullet holes and a water pump in case there were leaks.

The supplies, which included 25 litres of drinking water, lasted four days and had to be replenished by the rescuers, who were not long in coming because the buoys were anchored to the bottom at fixed points, so they could be checked daily. To make it easier to get to the boat or seaplane that came, there was even an inflatable lifeboat. Thanks to all this, many aviators managed to survive and, in fact, the Rettungsboje transcended their use by inspiring the current Rettungsbake (rescue beacons for hikers that are isolated in shallows of the German coast) and the covered life rafts of the ships.

Sources: La Batalla de Inglaterra (Stephen Bungay)/RAF Air Sea Rescue 1918-1986 (Diane Canwell y Jon Sutherland) / Luftwaffe-zur-See / LuftArchiv / Imperial War Museum / Wikipedia