Picture the scene over the grey Atlantic in 1943. A Luftwaffe fighter pilot spots a fat, slow British flying boat lumbering along at wave-top height, an unmissable target the size of a small ferry. Easy kill, surely. And yet, again and again, German pilots found reasons to be somewhere else. They had learned, the hard way, that this particular target shot back from every angle at once. They had a name for it: the Fliegendes Stachelschwein, the Flying Porcupine. Meet the Short Sunderland, the aircraft that turned defence into a deterrent and became one of the deadliest submarine hunters of the Second World War.

From ocean liner to war machine

The Sunderland was born in the same drawing office, and much the same decade, as one of the great glamour machines of the 1930s: the Short Empire, the elegant flying boat that carried Imperial Airways passengers and Royal Mail across the Empire in genuine luxury. When the Air Ministry issued a specification for a long-range ocean-reconnaissance flying boat, Short Brothers of Rochester already had the expertise, and the result, the S.25, shared a clear family resemblance with its civilian cousin: the same high wing, the same cavernous two-deck hull.

But the Sunderland was no airliner in uniform. It had a deeper, more warlike hull, a longer nose, and provision from the outset for turrets, bombs, mines and depth charges. The prototype first flew on 16 October 1937, and by the summer of 1938 the type was entering RAF service. When war broke out in September 1939, RAF Coastal Command had a few dozen on strength, forming its only genuine long-range eyes over the ocean. Inside, the crew of nine to eleven lived aboard for patrols that could stretch past thirteen hours, complete with bunks, a galley with a proper stove, and a flush toilet. It was, in every sense, a ship that flew.

Why the Germans called it the Porcupine

The nickname was earned, not invented by marketing. On 3 April 1940, an RAF Sunderland operating off Norway was jumped by six Junkers Ju 88 fighters. Rather than being swatted from the sky, the flying boat shot one down, damaged a second so badly it was forced to land, and drove the rest off. Word got around. The Sunderland’s guns were only rifle-calibre .303s at first, and they lacked range and punch, but there were an awful lot of them, and the aircraft itself was famously hard to kill.

Over the war the armament kept multiplying. What began as seven machine guns grew into a hedgehog of firepower: a powered nose turret, a four-gun tail turret, a dorsal turret, beam guns firing from hatches, and, on Australian-modified aircraft, four fixed guns in the nose that the pilot could fire while diving on a target. Late examples bristled with as many as sixteen to eighteen guns, some upgraded to hard-hitting .50 calibre. A lone Sunderland flying low over the sea, denying attackers the belly shot, was simply not worth the casualties.

The U-boat killer

Impressive as its self-defence was, the Sunderland’s real job was hunting. In the Battle of the Atlantic it patrolled the convoy approaches and the deadly Bay of Biscay, where German submarines transited to and from their French bases. Early anti-submarine weapons were almost comically bad: one bomb reportedly bounced off the sea and struck the aircraft that dropped it. That changed in early 1943 with Torpex-filled depth charges that sank to a set depth before exploding, and with ASV radar that let crews find surfaced U-boats charging their batteries at night.

The results speak for themselves. On 17 July 1940 an Australian-crewed Sunderland of No. 10 Squadron RAAF made the type’s first unassisted U-boat kill. By the end of the war, the meticulous tally kept by uboat.net credits Sunderlands with sharing in the destruction of at least 26 U-boats, and historian Andrew Hendrie reckons they participated in sinking or damaging around 56 German and Italian submarines all told. For an aircraft designed chiefly for reconnaissance, that is a formidable scoreboard.

“N for Nuts” and the fight of 2 June 1943

If one action captures the Sunderland’s character, it is the battle fought by EJ134 of No. 461 Squadron RAAF, call sign “N for Nuts”. On 2 June 1943, over the Bay of Biscay, Flight Lieutenant Colin Walker and his eleven-man crew were bounced not by one or two fighters but by eight Ju 88s. What followed was three-quarters of an hour of sheer violence: engines knocked out, fires aboard, gunners wounded, the radio smashed, the aircraft corkscrewing between the sea and the guns. When it was over, the crew claimed three Ju 88s destroyed and several more damaged, and the survivors nursed their wreck of an aircraft some 350 miles home to beach it in the Cornish surf at Praa Sands.

One crewman died in the battle; the rest waded ashore as the Sunderland broke up. There is a bitter coda: most of that crew were lost just over two months later in a replacement “N for Nuts”, shot down over the same waters. A memorial on the green at Praa Sands remembers them still.

The long, slow goodbye

Unlike most wartime aircraft, the Sunderland refused to retire when the shooting stopped. Its corrosion-proofed hull made it ideal for hauling salt into blockaded Berlin during the 1948 airlift, landing on the Havel until the lake iced over. It flew long patrols in the Korean War, and soldiered on with the RAF until 1959 and with the Royal New Zealand Air Force until 1967. Civilian conversions, the Hythe and the Sandringham, carried passengers into the 1970s, outlasting the glamorous Empire boat that had helped inspire them.

The Short Sunderland belongs to a vanished age of aviation, the last hurrah of the big flying boat before long concrete runways made it obsolete. But it deserves to be remembered as more than a curiosity. It was a floating fortress that lived on the water, patrolled for half a day at a stretch, killed submarines, rescued shipwrecked sailors, and defended itself so fiercely that the enemy’s own fighter pilots gave it a nickname out of respect. Slow, ungainly, unglamorous, and utterly indispensable, the Flying Porcupine earned every one of its quills.

A closer look inside the Short Sunderland.

Sources: Wikipedia (Short Sunderland; No. 461 Squadron RAAF); uboat.net; Naval Historical Foundation (review of Andrew Hendrie’s "Short Sunderland: the Flying Porcupines"); IWM War Memorials Register (Praa Sands memorial).