This history of world travellers will by no means be accurate if the giant flying boats were not mentioned prominently, before the Second World War it was widely considered to be the only way to build large airliners. With over 70% of the planet's surface covered in potential runways its easy to see why this school of thought was so popular.
A Flying Boat is a fixed-winged seaplane with a hull, that allows it to land on water, that usually has no type of landing gear to allow operation on land It differs from a floatplane as it uses a purpose-designed fuselage which can float, granting the aircraft buoyancy. Flying boats may be stabilized by under-wing floats or by wing-like projections, called sponsons, from the fuselage. Flying boats were some of the largest aircraft of the first half of the 20th century, exceeded in size only by bombers developed during World War II.
Austrian, aviation pioneer, Wilhelm Kress is credited with building the first seaplane in as early as 1898, that’s five years before the wright brothers' famous flight at Kitty Hawk. Unfortunately, the 30 hp Daimler engines were in no way powerful enough to take off and it later sank when one of its two floats collapsed without ever leaving the ground.
On 28 March 1910 Frenchman Henri Fabre successfully flew the first successful powered seaplane, the Gnome Omega-powered hydration, a trimaran floatplane. Fabre's first successful take-off and landing by a powered seaplane inspired other aviators and he designed floats for several other flyers. The first hydro-aeroplane competition was held in Monaco in March 1912, featuring aircraft using floats from Fabre, Curtiss, Tellier and Farman. This led to the first scheduled seaplane passenger services at Aix-les-Bains, using a five-seat Sanchez-Besa from 1 August 1912. Seeing the enormous potential of water-based aircraft the French Navy ordered its first floatplane in 1912.
French designer, François Denhaut, constructed the first seaplane with a fuselage forming a hull, the hull was designed to give hydrodynamic lift at take-off and It successfully flew on 13 April 1912, ushering in the era of the “Flying Boat”.
By the outbreak of the First World War considerable advances were made in flying boat design, John Cyril Porte developed a practical hull design with the distinctive "Felixstowe notch". Porte's first design to be implemented in Felixstowe was the Felixstowe Porte Baby, a large, three-engine biplane flying boat, powered by one central pusher and two outboard tractor Rolls-Royce Eagle engines.
Porte's innovation of the "Felixstowe notch" enabled the craft to overcome suction from the water quicker and break free for flight much easier. This made operating the craft far safer and more reliable. The "notch" breakthrough would soon after evolve into a "step", with the rear section of the lower hull sharply recessed above the forward lower hull section, and that characteristic became a feature of both flying boat hulls and seaplane floats. The resulting aircraft would be large enough to carry sufficient fuel to fly long distances and could berth alongside ships to take on more fuel.
In February 1917, the first prototype of the Felixstowe F.3 was flown. It was larger and heavier than the F.2, giving it greater range and heavier bomb load, but poorer agility. Approximately 100 Felixstowe F.3s were produced before the end of the war.
The Felixstowe F.5 was intended to combine the good qualities of the F.2 and F.3, with the prototype first flying in May 1918. The prototype showed superior qualities to its predecessors but, to ease production, the production version was modified to make extensive use of components from the F.3, which resulted in lower performance than the F.2A or F.3.
Porte's final design at the Seaplane Experimental Station was the 123 ft-span five-engine Felixstowe Fury triplane. F.2, F.3, and F.5 flying boats were extensively employed by the Royal Navy for coastal patrols, and to search for German U-boats. In 1918 they were towed on lighters towards the northern German ports to extend their range; on 4 June 1918, this resulted in three F.2As engaging in a dogfight with ten German seaplanes, shooting down two confirmed and four probable at no loss. As a result of this action, British flying boats were dazzle-painted to aid identification in combat.
The Curtiss Aeroplane and Motor Company independently developed its designs into the small Model "F" and the Model "C" for the U.S. Navy. Curtiss among others also built the Felixstowe F.5 as the Curtiss F5L, based on the final Porte hull designs and powered by American Liberty engines.
Meanwhile, the pioneering flying boat designs of François Denhaut had been steadily developed by the Franco-British Aviation Company into a range of practical craft. Smaller than the Felixstowes, several thousand FBAs served with almost all of the Allied forces as reconnaissance craft, patrolling the North Sea, Atlantic and Mediterranean oceans.
In Italy, several seaplanes were developed, starting with the L series, and progressing with the M series. The Macchi M.5 in particular was extremely manoeuvrable and agile and matched the land-based aircraft it had to fight. 244 were built in total. Towards the end of World War One, the aircraft was flown by the Italian Navy Aviation, the United States Navy and the United States Marine Corps airmen. Ensign Charles Hammann won the first Medal of Honor awarded to a United States naval aviator in an M.5
The Aeromarine Plane and Motor Company built some of the biggest seaplanes of the time in Keyport, New Jersey. Mr Uppercu built the factory on a 66-acre site in 1917 and Built the Aeromarine 75 and Aeromarine AMC flying Boats which with Aeromarine West Indies Airways flew Air Mail to Florida, Bahamas, and Cuba along with being passenger carriers.
The German aircraft manufacturing company Hansa-Brandenburg built flying boats starting with the model Hansa-Brandenburg GW in 1916. The Austro-Hungarian firm, Lohner-Werke also began building flying boats, starting with the Lohner E in 1914 and the later influential Lohner L version.
After the war, Flying Boats were once again used for peaceful purposes and John Curtiss’ NC-4 became the first aircraft to fly across the Atlantic Ocean in 1919, crossing via the Azores. Of the four that made the attempt, only one completed the flight. Before the development of highly reliable aircraft, the ability to land on water was a desirable safety feature for transoceanic travel.
In 1923, the first successful commercial flying boat service was introduced with flights to and from the Channel Islands. The British aviation industry was experiencing rapid growth and as a result, the Government decided that nationalization was necessary and ordered five aviation companies to merge to form the state-owned Imperial Airways of London (IAL). IAL became the international flag-carrying British airline, providing flying boat passenger and mail transport links between Britain and South Africa using aircraft such as the Short S.8 Calcutta.
In 1928, four Supermarine Southampton flying boats of the RAF Far East flight arrived in Melbourne, Australia. The flight was considered proof that flying boats had evolved to become reliable means of long-distance transport.
In the 1930s, flying boats made it possible to have regular air transport between the U.S. and Europe, opening up new air travel routes to South America, Africa, and Asia. Foynes, Ireland and Botwood, Newfoundland and Labrador were the termini for many early transatlantic flights. In areas where there were no airfields for land-based aircraft, flying boats could stop at small islands, rivers, lakes or coastal stations to refuel and resupply. The Pan Am Boeing 314 "Clipper" planes brought exotic destinations like the Far East within reach of air travellers and came to represent the romance of flight.
By 1931, mail from Australia was reaching Britain in just 16 days, less than half the time taken by sea. In that year, government tenders on both sides of the world invited applications to run new passenger and mail services between the ends of the British Empire, and Qantas and IAL were successful with a joint bid. A company under combined ownership was then formed Qantas Empire Airways. The new ten-day service between Rose Bay, New South Wales and Southampton was such a success with letter-writers that before long the volume of mail was exceeding aircraft storage space. A solution to the problem was found by the British government, who in 1933 had requested aviation manufacturer Short Brothers to design a big new long-range monoplane for use by IAL. Partner Qantas agreed to the initiative and undertook to purchase six of the new Short S23 "C" class or "Empire" flying boats.
Sir Alan Cobham devised a method of in-flight refuelling in the 1930s the Short Empire could be loaded with more fuel than it could take off with. Short Empire flying boats serving the trans-Atlantic crossing were refuelled over Foynes; with the extra fuel load, they could make a direct trans-Atlantic flight. A Handley Page H.P.54 Harrow was used as the fuel tanker.
The German Dornier Do X flying boat was noticeably different from its UK and U.S.-built counterparts. It had wing-like protrusions from the fuselage, called sponsons, to stabilize it on the water without the need for wing-mounted outboard floats. This feature was pioneered by Claudius Dornier during World War I on his Dornier Rs. I a giant flying boat, and was perfected on the Dornier Wal in 1924. The enormous Do X was powered by 12 engines and once carried 170 persons as a publicity stunt. It flew to America in 1930–31, crossing the Atlantic via an indirect route over 9 months. It was the largest flying boat of its time but was severely underpowered and was limited by a very low operational ceiling. Only three were built, with a variety of different engines installed, in an attempt to overcome the lack of power.
The Dornier Wal was "easily the greatest commercial success in the history of marine aviation". Over 250 were built in Italy, Spain, Japan, The Netherlands and Germany. Numerous airlines operated the Dornier Wal on scheduled passenger and mail services. Wals were used by explorers, for a number of pioneering flights, and by the military in many countries. Though having first flown in 1922, from 1934 to 1938 Wals operated the over-water sectors of the Deutsche Luft Hansa South Atlantic Airmail service.
The military value of flying boats was well-recognized, and every country bordering on water operated them in a military capacity at the outbreak of the war. They were utilized in various tasks from anti-submarine patrol to air-sea rescue and gunfire spotting for battleships. Aircraft such as the PBM Mariner patrol bomber, PBY Catalina, Short Sunderland, and Grumman Goose recovered downed airmen and operated as scout aircraft over the vast distances of the Pacific Theatre and the Atlantic. They also sank numerous submarines and found enemy ships. In May 1941 the German battleship Bismarck was discovered by a PBY Catalina flying out of Castle Archdale Flying boat base, Lower Lough Erne, Northern Ireland.
The largest flying boat of the war was the Blohm & Voss BV 238, which was also the heaviest plane to fly during World War II and the largest aircraft built and flown by any of the Axis Powers.
In November 1939, IAL was restructured into three separate companies: British European Airways, British Overseas Airways Corporation (BOAC), and British South American Airways, which merged with BOAC in 1949, with the change being made official on 1 April 1940. BOAC continued to operate flying boat services from the (slightly) safer confines of Poole Harbour during wartime, returning to Southampton in 1947. When Italy entered the war in June 1940, the Mediterranean was closed to allied planes and BOAC and Qantas operated the Horseshoe Route between Durban and Sydney using Short Empire flying boats.
The Martin Company produced the prototype XPB2M Mars based on their PBM Mariner patrol bomber, with flight tests between 1941 and 1943. The Mars was converted by the Navy into a transport aircraft designated the XPB2M-1R. Satisfied with the performance, 20 of the modified JRM-1 Mars were ordered. The first, named Hawaii Mars was delivered in June 1945, but the Navy scaled back its order at the end of World War II, buying only the five aircraft which were then on the production line. The five Mars were completed, and the last was delivered in 1947.
After World War II the use of flying boats rapidly declined for several reasons. The ability to land on water became less of an advantage owing to the considerable increase in the number and length of land-based runways during World War II. Further, as the reliability, speed, and range of land-based aircraft increased, the commercial competitiveness of flying boats diminished, and their design compromised aerodynamic efficiency and speed to accomplish the feat of waterborne take-off and landing. Competing with new civilian jet aircraft like the de Havilland Comet and Boeing 707 proved impossible.
The Hughes H-4 Hercules, in development in the U.S. during the war, was even larger than the BV 238 but it did not fly until 1947. The “Spruce Goose", as the 180-ton H-4 was nicknamed, was the largest flying boat ever to fly, carried out during Senate hearings into Hughes's use of government funds on its construction, the short hop of about a mile at 70 ft above the water by the "Flying Lumberyard" was claimed by Hughes as vindication of his efforts. Cutbacks in expenditure after the war and the disappearance of its intended mission as a transatlantic transport left it no purpose.
In 1944, the Royal Air Force began the development of a small jet-powered flying boat that it intended to use as an air defence aircraft optimised for the Pacific, where the relatively calm sea conditions made the use of seaplanes easier. By making the aircraft jet-powered, it was possible to design it with a hull rather than making it a floatplane. The Saunders-Roe SR.A/1 prototype first flew in 1947 and was relatively successful in terms of its performance and handling. However, by the end of the war, carrier-based aircraft were becoming more sophisticated, and the need for the SR.A/1 evaporated.
During the Berlin Airlift, which lasted from June 1948 until August 1949, 10 Sunderlands and two Hythes were used to transport goods from Finkenwerder on the Elbe near Hamburg to isolated Berlin, landing on the Havelsee beside RAF Gatow until it iced over. The Sunderlands were particularly used for transporting salt, as their airframes were already protected against corrosion from seawater. Transporting salt in standard aircraft risked rapid and severe structural corrosion in the event of spillage. In addition, three Aquila Airways flying boats were used during the airlift. This is the only known operational use of flying boats within central Europe.
The U.S. Navy continued to operate flying boats, notably the Martin P5M Marlin, until the late 1960s. The Navy even attempted to build a jet-powered seaplane bomber, the Martin Seamaster.
Bucking the trend, in 1948 Aquila Airways was founded to serve destinations that were still inaccessible to land-based aircraft. This company operated Short S.25 and Short S.45 flying boats out of Southampton on routes to Madeira, Las Palmas, Lisbon, Jersey, Majorca, Marseille, Capri, Genoa, Montreux and Santa Margherita. From 1950 to 1957, Aquila also operated a service from Southampton to Edinburgh and Glasgow. The flying boats of Aquila Airways were also chartered for one-off trips, usually to deploy troops where scheduled services did not exist or where there were political considerations. The longest charter, in 1952, was from Southampton to the Falkland Islands. In 1953 the flying boats were chartered for troop deployment trips to Freetown and Lagos and there was a special trip from Hull to Helsinki to relocate a ship's crew. The airline ceased operations on 30 September 1958.
The shape of the Short Empire, a British flying boat of the 1930s was a harbinger of the shape of 20th-century aircraft yet to come. Today, however, true flying boats have largely been replaced by seaplanes with floats and amphibious aircraft with wheels. The Beriev Be-200 twin-jet amphibious aircraft has been one of the closest "living" descendants of the earlier flying boats, along with the larger amphibious planes used for fighting forest fires
