Just keeping with the carrier/land-based/surprise concept.
Question is what is the key to a succesfull base-raid. The aircraft type, the absence of enemy fighter, air defence artillery or something else?
Is it simply the surprise effect? Enemy defenders still sleeping?
Also, I am struggling to find evidence of torpedoes used by air craft at scapa. Did the He-111J had the range with torpedoes?
A little highlight from OTL raids on Scapa:
"Air raids in Orkney
On 17 October 1939, three days after the sinking of the Royal Oak, Scapa Flow was attacked by German bombers. Most ships had sailed after the U-boat attack, but 'HMS Iron Duke' was there as a floating administration centre. She suffered severe damage and had to be towed to Ore Bay near Lyness and beached. On board were a number of the survivors of the Royal Oak.
The 226 Battery, comprising men from the Orkney and Caithness T.A., manning the anti-aircraft guns at Ore and Rysa in Hoy, shot down one of the Ju 88s. One of the crew escaped by parachute, but was badly burned. This was the first German aircraft of the war to be shot down on British soil by an anti-aircraft gun. The first German bomb of the war to land on British soil fell during a second raid later that day.
On Saturday 16 March 1940, at least fourteen German bombers attacked Scapa Flow, the aerodrome at Hatston and other targets. Also attacked was the small group of houses at the Brig O’ Waithe, Stenness. Twenty-two high explosive bombs fell around the houses, one of which suffered a direct hit. James Isbister was killed by a piece of shrapnel, his wife and baby were uninjured. He had the sad distinction of being the first civilian casualty of World War 2.
Barrage fire was introduced in April 1940. This involved all anti-aircraft guns, both on land and on ships, firing rapidly at a certain height. This created a blanket of bursting shells to prevent the German bombers from diving at their targets.
A heavy attack on 8 April was met with a powerful barrage. The following evening Norway was invaded, and Scapa Flow saw its heaviest ever raid. Sixty Ju 88s and HE 111s launched an attack in an attempt to put the naval base out of operation. The raid ended in failure. It was the last major raid to be launched against Scapa Flow."