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Supermarine Southampton

The Supermarine Southampton was a flying boat of the interwar period designed and produced by the British aircraft manufacturer Supermarine.

It was one of the most successful flying boats of the era.

The Southampton was derived from the experimental Supermarine Swan, and thus was developed at a relatively high pace.

Demand for the type was such that Supermarine had to expand its production capacity to keep up.

During August 1925, the Southampton entered service with the Royal Air Force (RAF), with whom the type gained a favourable reputation via a series of long-distance formation flights.

Further customers emerged for the type, including the Imperial Japanese Navy, Argentine Naval Aviation, and Royal Danish Navy.

During August 1925, the first Southamptons entered service with the RAF, the type being initially assigned to No. 480 (Coastal Reconnaissance) Flight, based at RAF Calshot. 

As validated through a series of exercises, the ability of the Southampton to independently operate, even within inhospitable weather conditions, was well proven. 

Andrews and Morgan observed that the Southampton quickly proved itself to have primacy amongst European flying boats of the era, a fact that was promptly demonstrated by its overseas activities.

Amongst the tasks of which RAF Southamptons performed was a series of “showing the flag” long-distance formation flights.

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 the Far East Flight, setting out from Felixstowe via the Mediterranean and India to Singapore.

These aircraft featured various technical changes, including enlarged fuel tanks composed of tinned steel, increased oil tankage, greater radiator surface area, and the removal of all armaments.

According to Andrews and Morgan, the Southampton acquired considerable fame amongst the general public from these flights; Supermarine also shared in this reputation gain.

There were also practical benefits of these flights, as new anti-corrosion techniques were developed as a result of feedback.


Different powerplants were fitted in variants:

Mk I

Napier Lion V engine, wooden hull. 23 built.


Napier Lion Va, 39 built

Saunders A.14


Lorraine-Dietrich 12E.

Five wooden hulled + three metal hulled aircraft.


Hispano-Suiza 12Nbr.

Six built.

Bristol Jupiter IX and Rolls-Royce Kestrel in experiments

Mk IV 

Supermarine Scapa prototype



49 ft 8+12 in (15.151 m)


75 ft 0 in (22.86 m)


20 ft 5 in (6.22 m)

Wing area

1,448 sq ft (134.5 m2)

Empty weight

9,697 lb (4,398 kg)

Gross weight

15,200 lb (6,895 kg)

Max take-off weight

18,000 lb (8,165 kg) (overload)


2 × Napier Lion VA inline W block,

500 hp (370 kW) each


Maximum speed

95 mph (153 km/h, 83 kn) at sea level


544 mi (875 km, 473 nmi) at 86 mph (75 kn; 138 km/h) and 2,000 ft (610 m)


6.3 hours

Service ceiling

5,950 ft (1,810 m)

Absolute ceiling

8,100 ft (2,500 m)

Rate of climb

368 ft/min (1.87 m/s)

Time to altitude

29 minutes, 42 seconds to 6,000 ft (1,800 m)



Three × .303 in (7.7 mm) Lewis guns,

One in bows


Two amidships


1,100 lb of bombs under the wings

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