Flying boat

Short S23"C" Class or "Empire" flying boat

APBM Marinertakes off in 1942

Dornier X in 1932

Aflying boatis a type offixed-wingedseaplanewith ahull,allowing it to land on water.It differs from afloatplanein having afuselagethat is purpose-designed for flotation, while floatplanes rely on fuselage-mounted floats forbuoyancy.

Though a flying boat’s fuselage provides buoyancy, it may also utilize under-wingfloatsor wing-like hull projections (calledsponsons) for additional stability.

Ascending into common use during theFirst World War,flying boats rapidly grew in both scale and capability during theinterwar period,during which time numerous operators found commercial success with the type. Flying boats were some of the largest aircraft of the first half of the 20th century, exceeded in size only bybombersdeveloped during theSecond World War.Their advantage lay in using water instead of expensive land-based runways, making them the basis for internationalairlinesin the interwar period. They were also commonly used asmaritime patrol aircraftandair-sea rescue,particularly during times of conflict. Flying boats such as thePBY CatalinaandShort Sunderlandplayed key roles in both thePacific Theaterand theAtlanticof the Second World War.

The popularity of flying boats gradually tailed off during theCold Warera, partially because of the difficulty in maintaining operations in inclement weather when sea conditions may easily prevent taking off and landing while land based aircraft are unaffected, and investments in airports during the conflict that eased the introduction of larger, and more efficient, land-based airliners. Despite being largely overshadowed, limited use of the type continued with some operators, such as in the case of theShin Meiwa US-1Aand theMartin JRM Mars.In the 21st century, flying boats maintain a few niche uses, such asdropping water on forest fires,air transport around archipelagos, and access to undeveloped areas. Many modern seaplane variants, whether float or flying boat types, are convertible amphibious aircraft where either landing gear or flotation modes may be used to land and take off.

History

Early floatplanes

Gabriel Voisin,air pioneer, next toHenry Farman(left), in 1908

The quest for an aircraft that could take off or land from water began with float planes, which are not flying boats.

The FrenchmanAlphonse Pénaudfiled the first patent for a flying machine with a boat hull and retractable landing gear in 1876 but failed to build one. AustrianWilhelm Kressis credited by some with attempting to build the first successful seaplaneDrachenflieger,afloatplane,in 1898, although its two 30 hp Daimler engines were inadequate for take-off and it later sank when one of its two floats collapsed.

On 6 June 1905,Gabriel Voisintook off and landed on the RiverSeinewith a towed kite glider on floats. The first of his unpowered flights was 150 yards.He later built a powered floatplane in partnership withLouis Blériot,but the machine was unsuccessful.

Other pioneers also attempted to attach floats to aircraft in Britain, Australia, France and the USA.

On 28 March 1910, FrenchmanHenri Fabreflew the first successful powered floatplane, theGnome Omega–poweredHydravion,a trimaran floatplane.Fabre's first successful take off and landing by a powered floatplane inspired other aviators and he designed floats for several other flyers. The first hydro-aeroplane competition was held inMonacoin March 1912, featuring aircraft using floats from Fabre, Curtiss, Tellier and Farman. This led to the first scheduled seaplane passenger services atAix-les-Bains,using a five-seat Sanchez-Besa from 1 August 1912.TheFrench Navyordered its first floatplane in 1912.

None of these crafts to date were flying boats.

In 1911–12,François Denhautconstructed thefirst flying boat,with a fuselage forming a hull, using various designs to givehydrodynamic liftat take-off. Its first successful flight was on 13 April 1912.

Throughout 1910 and 1911 American pioneering aviatorGlenn Curtissdeveloped his floatplane into the successfulCurtiss Model Dland-plane, which used a larger central float and sponsons. Combining floats with wheels, he made the firstamphibianflights in February 1911 and was awarded the firstCollier Trophyfor US flight achievement. From 1912 his experiments resulted in the 1913Model EandModel F,which he called "flying-boats".

In February 1911, theUnited States Navytook delivery of the Curtiss Model E, and soon tested landings on and take-offs from ships using the Curtiss Model D.

In Britain, Captain Edward Wakefield andOscar Gnosspeliusbegan to explore the feasibility of flight from water in 1908. They decided to make use ofWindermerein theLake District,England's largestlaketo test their floatplane. The latter's first attempts to fly attracted large crowds, though the aircraft failed to take off and required a re-design of the floats incorporating features of Borwick's successful speed-boat hulls. Meanwhile, Wakefield ordered a floatplane similar to the design of the 1910 Fabre Hydravion. By November 1911, both Gnosspelius and Wakefield had aircraft capable of flight from water and awaited suitable weather conditions. Gnosspelius's flight was short-lived as the aircraft crashed into the lake. Wakefield's pilot however, taking advantage of a light northerly wind, successfully took off and flew at a height of 50 feet to Ferry Nab, where he made a wide turn and returned for a perfect landing on the lake's surface.

Birth of an industry

Curtiss NCFlying Boat "NC-3" skims across the water before takeoff, 1919

In 1913, theDaily Mailnewspaperput up a £10,000 prizefor thefirst non-stop aerial crossing of the Atlanticwhich was soon "enhanced by a further sum" from the Women's Aerial League of Great Britain. American businessmanRodman Wanamakerbecame determined that the prize should go to an American aircraft and commissioned theCurtiss Aeroplane and Motor Companyto design and build an aircraft capable of making the flight. Curtiss' development of theFlying Fishflying boat in 1913 brought him into contact withJohn Cyril Porte,a retiredRoyal Navylieutenant, aircraft designer and test pilot who was to become an influential British aviation pioneer. Recognising that many of the early accidents were attributable to a poor understanding of handling while in contact with the water, the pair's efforts went into developing practical hull designs to make the transatlantic crossing possible.

At the same time the British boat building firmJ. Samuel WhiteofCoweson theIsle of Wightset up a new aircraft division and produced a flying boat in the United Kingdom. This was displayed at the London Air Show at Olympia in 1913.In that same year, a collaboration between the S. E. Saunders boatyard ofEast Cowesand theSopwith Aviation Companyproduced the "Bat Boat", an aircraft with aconsutalaminated hull that could operate from land or on water, which today we call anamphibious aircraft.The "Bat Boat" completed several landings on sea and on land and was duly awarded theMortimer Singer Prize.It was the first all-British aeroplane capable of making six return flights over five miles within five hours.

In the U.S. Wanamaker's commission built on Glen Curtiss' previous development and experience with the Model Ffor the U.S. Navy which rapidly resulted in theAmerica,designed under Porte's supervision following his study and rearrangement of the flight plan; the aircraft was a conventionalbiplanedesign with two-bay, unstaggered wings of unequal span with two pusherinline enginesmounted side-by-side above thefuselagein the interplane gap. Wingtip pontoons were attached directly below the lower wings near their tips. The design (later developed into theModel H), resembled Curtiss' earlier flying boats, but was built considerably larger so it could carry enough fuel to cover 1,100 mi (1,800 km). The three crew members were accommodated in a fully enclosed cabin.

Trials of theAmericabegan on 23 June 1914 with Porte also as Chief Test Pilot; testing soon revealed serious shortcomings in the design; it was under-powered, so the engines were replaced with more powerful engines mounted in a tractor configuration. There was also a tendency for the nose of the aircraft to try to submerge as engine power increased while taxiing on water. This phenomenon had not been encountered before, since Curtiss' earlier designs had not used such powerful engines nor large fuel/cargo loads and so were relatively more buoyant. In order to counteract this effect, Curtiss fittedfinsto the sides of the bow to add hydrodynamic lift, but soon replaced these withsponsons,a type of underwater pontoon mounted in pairs on either side of a hull. These sponsons (or their engineering equivalents) and the flared, notched hull would remain a prominent feature of flying boat hull design in the decades to follow. With the problem resolved, preparations for the crossing resumed. While the craft was found to handle "heavily" on takeoff, and required rather longer take-off distances than expected, thefull moonon 5 August 1914 was selected for the trans-Atlantic flight; Porte was to pilot theAmericawithGeorge Hallettas co-pilot and mechanic.

First World War

Curtiss and Porte's plans were interrupted by the outbreak of the First World War. Porte sailed for England on 4 August 1914 and rejoined the Navy, as a member of theRoyal Naval Air Service.Appointed Squadron Commander ofRoyal Navy Air Station Hendon,he soon convinced the Admiralty of the potential of flying boats and was put in charge of thenaval air stationatFelixstowein 1915. Porte persuaded theAdmiraltyto commandeer (and later, purchase) theAmericaand a sister craft from Curtiss. This was followed by an order for 12 more similar aircraft, one Model H-2 and the remaining asModel H-4's. Four examples of the latter were assembled in the UK bySaunders.All of these were similar to the design of theAmericaand, indeed, were all referred to asAmericas in Royal Navy service. The engines, however, were changed from the under-powered 160 hp Curtiss engines to 250 hpRolls-Royce Falconengines. The initial batch was followed by an order for 50 more (totalling 64Americasoverall during the war).Porte also acquired permission to modify and experiment with the Curtiss aircraft.

The Curtiss H-4s were soon found to have a number of problems; they were underpowered, their hulls were too weak for sustained operations and they had poor handling characteristics when afloat or taking off.One flying boat pilot, Major Theodore Douglas Hallam, wrote that they were "comic machines, weighing well under two tons; with two comic engines giving, when they functioned, 180 horsepower; and comic control, being nose heavy with engines on and tail heavy in a glide."

Felixstowe F.2A,the first production flying boat, and the basis for future development.

At Felixstowe, Porte made advances in flying boat design and developed a practical hull design with the distinctive "Felixstowe notch".Porte's first design to be implemented in Felixstowe was theFelixstowe Porte Baby,a large, three-enginedbiplaneflying-boat, powered by one central pusher and two outboard tractorRolls-Royce Eagleengines.

Porte modified an H-4 with a new hull whose improved hydrodynamic qualities made taxiing, take-off and landing much more practical, and called it theFelixstowe F.1.

Porte's innovation of the "Felixstowe notch" enabled the craft to overcome suction from the water more quickly and break free for flight much more easily. This made operating the craft far safer and more reliable, although similar devices had been in use in France since 1911. 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 floatplane 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.

Porte then designed a similar hull for the largerCurtiss H-12flying boat which, while larger and more capable than the H-4s, shared failings of a weak hull and poor water handling. The combination of the new Porte-designed hull, this time fitted with two steps, with the wings of the H-12 and a new tail, and powered by twoRolls-Royce Eagleengines, was named the Felixstowe F.2 and first flew in July 1916,proving greatly superior to the Curtiss on which it was based. It was used as the basis for all future designs.It entered production as the Felixstowe F.2A, being used as a patrol aircraft, with about 100 being completed by the end of World War I. Another seventy were built, and these were followed by two F.2c, which were built at Felixstowe.

TheFelixstowe F.5,designed byLieutenant CommanderJohn Cyril Porteat theSeaplane Experimental Station,Felixstowe

TheFelixstowe F.5was 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.

The Felixstowe flying boats were extensively employed by the Royal Navy for coastal patrols, including searching for GermanU-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 with ten German seaplanes, shooting down two confirmed and four probables at no loss.As a result of this action, British flying boats weredazzle-paintedto aid identification in combat.

Felixstowe F5Lunder construction at theNaval Aircraft Factory,Philadelphia, circa 1920.

TheCurtiss Aeroplane and Motor Companyindependently developed its designs into the small Model "F", the larger Model "K" (several of which were sold to the Russian Naval Air Service), 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 AmericanLiberty engines.

Meanwhile, the pioneering flying boat designs of François Denhaut had been steadily developed by theFranco-British AviationCompany 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 flying boats were developed, starting with the L series, and progressing with the M series. TheMacchi M.5in 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 the First World War, the aircraft were flown by the Italian Navy Aviation, the United States Navy and 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.

TheAeromarine Plane and Motor Companymodified the Felixstowe F.5 into Aeromarine 75 airliner flying boats which withAeromarine West Indies Airwaysflew Air Mail to Florida, Bahamas, and Cuba along with being passenger carriers.

The German aircraft manufacturing companyHansa-Brandenburgbuilt flying boats starting with the modelHansa-Brandenburg GWin 1916. TheAustro-Hungarianfirm,Lohner-Werkebegan building flying boats, starting with theLohner Ein 1914 and the later (1915)Lohner Lwhich was copied widely.

Interwar period

TwoSupermarine Southamptonsin 1925

Consolidated flying boat produced for Japan, which evaluated the type in the 1930s

In September 1919, British companySupermarinestarted operating the first flying boat service in the world, fromWoolstontoLe HavreinFrance,but it was short-lived.

A CurtissNC-4became the first aircraft to fly across the Atlantic Ocean in 1919, crossing via theAzores.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 theChannel Islands.The British aviation industry was experiencing rapid growth. The Government decided that nationalization was necessary and ordered five aviation companies to merge to form the state-ownedImperial Airwaysof London (IAL). IAL became the internationalflag-carryingBritish airline, providing flying boat passenger and mail transport links between Britain andSouth Africausing aircraft such as theShort S.8 Calcutta.

Flying boats ofAd Astra AeroS.A. atZürichhornwater airport;Uetlibergin the background (~1920)

During the 1920s, theRoyal Air Force(RAF) Far East flight performed a series of "showing the flag" long-distance formation flights using the newly developedSupermarine Southampton.Perhaps the most notable of these flights was a 43,500 km (27,000 mi) expedition conducted during 1927 and 1928; it was carried out by four Southamptons of theFar East Flight,setting out from Felixstowe via the Mediterranean and India toSingapore.Both the RAF and Supermarine acquired considerable acclaim from these flights, as well as proving 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,IrelandandBotwood,Newfoundland and Labradorwere the termini for many early transatlantic flights. In areas where there were no airfields for land-based aircraft, flying boats could stop at small island, river, lake or coastal stations to refuel and resupply. ThePan AmBoeing 314 Clipperplanes brought exotic destinations like the Far East within reach of air travelers 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 theBritish Empire,andQantasand IAL were successful with a joint bid. A company under combined ownership was then formed, Qantas Empire Airways. The new ten-day service betweenRose Bay, New South Wales(nearSydney), andSouthamptonwas such a success with letter-writers that before long the volume of mail was exceeding aircraft storage space.

A better solution to the problem was sought by the British government during the early 1930s, who released a specification calling for a new large aircraft capable of carrying up to 24 passengers in spacious comfort along with adequate room forairmailor freight while simultaneously being capable of acruising speedof 170 mph and a range of at least 700 miles; the capacity for an extended range of 2,000 miles to serve theNorth Atlanticroute was also stipulated.Originally intended for use by IAL, partner Qantas agreed to the initiative and undertook to purchase six of the newShort S23 "C" class or "Empire"flying boats as well. Being ordered from aviation manufacturerShort Brothers,the Empire was reportedly hailed as being "one of the world's boldest experiments in aviation", while early sceptics referred to the order less favourably as being a 'gamble'.IAL were so impressed by the Empire that it placed a follow-on order for another 11; when combined with the original order for 28 flying boats, this was the largest single order to have ever been placed for a British civil aircraft at that time.

"Maia and Mercury",just before the first trans-Atlantic flight, August 1938

Delivering the mail as quickly as possible generated a lot of competition and some innovative designs. One variant of the Short Empire flying boats was the strange-looking "Maia and Mercury".It was a four-enginedfloatplane"Mercury" (the winged messenger) fixed on top of "Maia", a heavily modified Short Empire flying boat.The larger Maia took off, carrying the smaller Mercury loaded to a weight greater than it could take off with. This allowed the Mercury to carry sufficient fuel for a direct trans-Atlantic flight with the mail.Unfortunately this was of limited usefulness, and the Mercury had to be returned from America by ship. The Mercury did set a number of distance records beforein-flight refuellingwas adopted.

Sir Alan Cobhamdevised a method of in-flight refuelling in the 1930s. In the air, 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 refueled over Foynes; with the extra fuel load, they could make a direct trans-Atlantic flight. AHandley Page H.P.54 Harrowwas used as the fuel tanker.

Dornier Do Xover a seaport town in the Baltic, 1930

The GermanDornier Do Xflying boat was noticeably different from its UK and U.S.-built counterparts.It had wing-like protrusions from the fuselage, calledsponsons,to stabilize it on the water without the need for wing-mounted outboard floats. This feature was pioneered byClaudius Dornierduring the First World War on his Dornier Rs. I giant flying boat, and perfected on theDornier Walin 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. Two of these were sold to Italy.

TheDornier Walwas "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 theDeutsche Luft HansaSouth Atlantic Airmail service.

Second World War

PBY CatalinaatNaval Air Station Jacksonville,circa 1943

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 theSecond World War.Flying boats such as thePBM Marinerpatrol bomber,PBY Catalina,Short Sunderland,andGrumman Goosewere procured in large numbers. The Sunderland, which was developed in parallel to the civilian Empire flying boat, was one of the most powerful and widely used flying boats throughout the conflict,while Catalinas were one of the most produced ASW of the war, with over 2,661 being produced in the US alone.

Flying boats were commonly utilized to conduct various tasks, fromanti-submarinepatrol toair-sea rescueandgunfire spottingfor battleships. They would recover downed airmen and operate as scout aircraft over the vast distances of thePacific Theaterand theAtlantic,locating enemy vessels and sinking numerous submarines.In May 1941, theGerman battleshipBismarckwas discovered by a PBY Catalina flying out ofCastle Archdale Flying boat base,Lower Lough Erne,Northern Ireland.A flight of Catalinas spotted the Japanese fleet approachingMidway Island,beginning theBattle of Midway.

On 3 April 1940, a single Sunderland operating offNorwaywas attacked by six GermanJunkers Ju 88Cfighters; during the engagement, it shot one down and damaged another until it retreated and drove off the rest. The Germans reputedly nicknamed the Sunderland theFliegendes Stachelschwein( "Flying Porcupine" ) due to its defensive firepower.Sunderlands in the Mediterranean theatre proved themselves on multiple high-profile occasions, flying many evacuation missions during theGerman seizureofCrete,each carrying as many as 82 passengers. One Sunderland flew the reconnaissance mission to observe the Italian fleet at anchor inTarantobefore the famousRoyal NavyFleet Air Arm'storpedo attack on 11 November 1940.

The prototypeBV 238 V1in June 1944

The largest flying boat of the war was theBlohm & Voss BV 238,which was also the heaviest plane to fly during the Second World War and the largest aircraft built and flown by any of theAxis Powers.Only the first prototype ever flew, commencing flight trials in April 1944.Months later, it wasstrafedand partially sunk while moored onLake Schaal,to the east ofHamburg;it never returned to flight, instead being intentionally sunk in deep water after the end of the conflict.

Kawanishi H8K,1941–1945

TheImperial Japanese Navyoperated what has been often described as the best flying boat of the conflict, theKawanishi H8K.Its design was based upon its immediate predecessor, theKawanishi H6K,but was a considerably larger and longer-ranged aircraft designed at the request of the Navy just prior to the outbreak of war.On the night of 4 March 1942, two H8Ks conducted thesecond raid on Pearl Harbor,refuelling en route bysubmarineatFrench Frigate Shoalsin order to achieve the necessary range; poor visibility caused this attack on Pearl Harbor to fail to accomplish any significant damage.An improved H8K2 variant of the type, featuring extremely heavy defensive armament, was also introduced.

In November 1939, IAL was restructured into three separate companies:British European Airways,British Overseas Airways Corporation(BOAC), andBritish 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 ofPoole Harbourduring wartime, returning toSouthamptonin 1947.When Italy entered the war in June 1940, the Mediterranean was closed to allied planes, and BOAC andQantasoperated theHorseshoe Routebetween Durban and Sydney usingShort Empireflying boats.

The Martin Company produced the prototypeXPB2M Marsbased 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 of the five production Mars flying boats entered service ferrying cargo toHawaiiand the Pacific Islands on 23 January 1944.Following the end of the conflict, the Navy opted to scaled back their order, buying only the five aircraft. The five Mars were completed, and the last delivered in 1947.

The U.S. used several 4-engine flying boats during World War II, including those that had been operating as civilian airliners. This included fiveBoeing B-314 Clippers,four more as the C-98s; twoMartin M-130 Clippers,a Martin XPB2M-1/XPB2M-1R prototype, and oneJRM-1 Mars;threeSikorsky VS-44s(JR2S-1). However, the main 4-engined flying boat of the U.S. forces was thePB2Y Coronado,of which nearly 220 were used in several versions:maritime patrol, bombing, medical/hospital transport, and for regular cargo; it also served with British forces in theBattle for the Atlantic.

One of the features of flying boats that was useful for search and rescue, was the ability to land on the water and not only pull out people from the water but stay there. One of the famous cases of this was the sinking of theIndianapolis,which went down on 31 July 1945, leaving hundreds of sailors in the water. Once it was realized it was missing, it was searched for, and the first to arrive was an amphibiousPBY-5A Catalinapatrol plane flown by Lieutenant Commander (USN)Robert Adrian Marks.Marks and his flight crew spotted the survivors and dropped life rafts; one raft was destroyed by the drop, while others were too far away from the exhausted crew. Against standing orders not to land in the open ocean, given the unique situation and lives at risk, Marks took a vote of his crew and decided to land the aircraft in twelve-foot (3.7 m) swells. He was able to maneuver his craft to pick up 56 survivors. Space in the plane was limited, so Marks had men lashed to the wing with parachute cord. The aircraft was unflyable with so many on it but could still float. This protected many of the exhausted men from being eaten by sharks or drowning while waiting for the main rescue force to arrive. After nightfall, the destroyer escortUSSCecil J. Doyle,the first of seven rescue ships, used its searchlight as a beacon and instilled hope in those still in the water.Cecil J. Doyleand six other ships picked up the remaining survivors. After the rescue, the PBY was sunk byCecil J. Doyleto scuttle it.

Post-War

Hughes H-4 Hercules

Saunders-Roe SR.A/1

After the end of the Second World War, 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 the conflict. Furthermore the commercial competitiveness of flying boats diminished, as their design compromised aerodynamic efficiency and speed in order to accommodate waterborne takeoff and landing. New land-based airliners such as theLockheed ConstellationandDouglas DC-4were developed with comparable reliability, speed, and long-range. The new landplanes were relatively easy to fly, and did not require the extensive pilot training programs mandated for seaplane operations. One of the 314's most experienced pilots said, "We were indeed glad to change to DC-4s, and I argued daily for eliminating all flying boats. The landplanes were much safer. No one in the operations department... had any idea of the hazards of flying boat operations. The main problem now was lack of the very high level of experience and competence required of seaplane pilots".

TheHughes 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. TheSpruce Goose,as the 180-ton H-4 was nicknamed, was the largest flying boat ever to fly. Carried out during Senate hearings into Hughes' 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 the H-4's vindication.Cutbacks in expenditure after the war and the disappearance of its intended mission as a transatlantic transport left the H-4 with no purpose. Despite never flying again, a full-time crew of 300 workers maintained the H-4 in a flightworthy condition in a climate-controlled hangar up until Hughes' death in 1976.

In early 1944, the BritishAir Ministryissued a contract for the production of a smalljet-poweredflying boat, theSaunders-Roe SR.A/1,that was intended for use as anair defenceaircraft optimised for use in the Pacific theatre.By adopting jet propulsion for the flying boat, it was possible to design it with a hull, rather than making it afloatplane,and thus eliminating the performance handicaps typically imposed upon floatplanes. It was projected to be capable of attaining speeds of up to 520 mph at 40,000 ft.Due to the SR.A/1's perceived value in the war against Imperial Japan, measures taken at an early stage of development towards immediate quantity production.However, due to the end of the conflict, pressure for the SR.A/1 quickly dissipated.

On 16 July 1947, the SR.A/1 prototype performed its maiden flight, quickly proving its soundness in terms of its performance and handling.However, officials judged that such an aircraft was unnecessary, and that the aircraft carrier had demonstrated a far more effective way to project airpower over the oceans.During late 1950, shortly after the outbreak of theKorean War,interest in the SR.A/1 programme was briefly resurrected amongst British and American officials, with whom data had been shared in the project.However, the flying boat fighter was found to be obsolete in comparison to increasingly capable land-based fighters, leading to a second and final cancellation.

During theBerlin Airlift(which lasted from June 1948 until August 1949) tenSunderlandsand twoHytheswere used to transport goods fromFinkenwerderon theElbenearHamburgto isolated Berlin, landing on the Havelsee besideRAF Gatowuntil 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 a spillage. In addition, threeAquila Airwaysflying boats were used during the airlift.

Bucking the trend, in 1948 Aquila Airways was founded to serve destinations that were still inaccessible to land-based aircraft.This company operatedShort S.25andShort S.45flying boats out of Southampton on routes toMadeira,Las Palmas,Lisbon,Jersey,Majorca,Marseille,Capri,Genoa,MontreuxandSanta Margherita.From 1950 to 1957, Aquila also operated a service fromSouthamptontoEdinburghandGlasgow.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 theFalkland Islands.In 1953, the flying boats were chartered for troop deployment trips toFreetownandLagosand there was a special trip fromHulltoHelsinkito relocate a ship's crew.The airline ceased operations on 30 September 1958.

Saunders-Roe PrincessG-ALUNat the Farnborough SBAC Show in September 1953

On 22 August 1952, theSaunders-Roe Princess,one of the largest and luxurious flying boats ever developed, performed its maiden flight.While flight testing of the innovative and ambitious flying boat went relatively smoothly, determining that the Princess was indeed capable of achieving its envisioned performance figures, only one prototype of the type would ever fly.Despite the granting of acertificate of airworthinessand representing the pinnacle of flying boat development of the era, no customers were willing to place firm orders for the Princess. This is despite reports that several would-be operators, includingAquila AirwaysandAero Spacelines,had attempted to purchase examples.

In 1951, BOAC performed an in-depth reevaluation of its standing requirements, and determined that the airline had no present need for the Princess, or any new large flying boat. The airline had already chosen to terminate its existing flying boat services during the previous year.Up until 1974,Ansett Australiaoperated a flying boat service from Rose Bay toLord Howe IslandusingShort Sandringhams.

The US Navy continued to operate flying boats (notably theMartin P5M Marlin) until the late 1960s. During the 1950s, the US Navy had encouraged the development of a jet-powered flying boat bomber, theMartin P6M Seamaster;however, its development was protracted by unfavourable handling characteristics above Mach 0.8, including rapid changes in directional trim, severebuffeting,and wing drop, which made it unfeasible for service until these tendencies were rectified.Following the US Navy's withdrawal of support, Martin tried unsuccessfully to market the SeaMaster to the civilian market, rebranding it as theSeaMistress,but the initiative picked up no takers.

During the 1950s, the Japanese aircraft manufacturerShinMeiwa Industriesconducted internal design studies into developing flying boats that would exhibit greater levels of seaworthiness than their predecessors.Over the following decade, the company developed theShin Meiwa US-1A,a new generation flying boat, to meet Japan's requirement for a maritime patrol aircraft capable of ASW operations. The initial model, designatedPS-1,was quickly followed by a dedicatedsearch-and-rescue(SAR) variant, theUS-1,although this was technically an amphibian rather than a flying boat through its modified designs.Shin Meiwa developed further flying boat concepts around this period, including theShin Meiwa MS(Medium Seaplane) a 300-passenger long-range flying boat with its own beaching gear; and the gargantuanShin Meiwa GS(Giant Seaplane) with a capacity of 1200 passengers seated on three decks.

Twenty-first century developments

Canadair CL-215 is used for dropping water on forest fires

ShinMaywa flying boat of the JMSDF

The shape of theShort 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 floatplanes oramphibious aircraftwith wheels. TheBeriev Be-200twin-jet amphibious aircraft is used for fighting forest fires. There are also several experimental/kit amphibians such as theVolmer Sportsman,Quikkit Glass Goose,Airmax Sea Max,Aeroprakt A-24,andSeawind 300C.

TheShinMaywa US-2is a largeSTOLamphibious aircraft designed for air-sea rescue work, derived from the earlier US-1. The first example was delivered to theJapan Maritime Self Defense Forcein 2009; the service has replaced its US-1 fleet with the US-2.A civilian-orientated fire-fighting variant of the US-2 has also been designed and promoted to prospective customers.

TheCanadair CL-415,an improved model of theCanadair CL-215,remains in production during the twenty-first century.The type has been primarily used for forest fire suppression, but has also seen use in other capacities, such as a maritime patrol aircraft.

The German companyDornier Seawings,an off-shoot of the original Dornier company, has repeatedly announced plans to launch production of itsSeaStarcomposite flying boat.In February 2016, Dornier launched the improved CD2 SeaStar.

During the 2010s, the state-owned companyAviation Industry Corporation of China(AVIC) launched a program to develop a massive new amphibian, theAVIC AG600.On 24 December 2017, it made itsmaiden flightfromZhuhai Jinwan Airport.

TheICON A5is an amphibious aircraft in thelight-sportclass. TheProgressive Aerodyne Seareyis an amphibious aircraft in thelight-sportclass, available as a kit built experimental or factory built aircraft. Shortly after thedissolution of the Soviet Uniontwo separatedscientific production associations (NPO)inSamarastarted to make flying boats for a new developing russian general aviation. Today NPO Aerovolga makes itsLaseries with La-8 being its latest while NPO Chaika makesLseries with L-65 being its latest in a line-up.

See also

• Ground effect vehicle
• List of flying boats and floatplanes
• Maritime patrol aircraft

References

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External links

• When Boats Had Wings, June 1963Archived6 October 2012 at theWayback Machinedetail articlePopular Science.
• The Flying BoatsonYouTube:BBC documentary film, 1980.