You can't make any meaningful comment on the accuracy of any sight based on one raid. Of the aircraft attacking, eighteen were equipped with the SABS and twelve with the Mk XIV sight and nobody knows whose bombs went where (see Bomber Command's ORS Report S.218). It is, in the context of a discussion of the accuracy of SABS, almost completely irrelevant. In any case three bombs struck Tirpitz and at least another seven (maybe ten, depending who you believe) landed within the torpedo nets, three very close to the ship, which is remarkably accurate bombing. Six of twenty nine bombs dropped either hit or landed close enough to severely damage the target. Whether a specially trained Norden equipped unit of US bombers in Europe could have come close to this is a moot point as it couldn't have carried a tallboy to make the attempt. The Americans had earlier declined to make the Norden sight available to the British.
The facts are that the SABS, of which less than 1,000 were ever made, in the hands of No. 617 Squadron, achieved an average radial error of 125 yards in all assessed operations between January and March 1945. Given that many of these raids were with special ordnance almost all were assessed.
The Mk XIV bomb sight, used by two other specially trained 'precision' squadrons achieved an error of 195 yards in the same period. The SABS was statistically and in reality a more accurate sight. The above figures were rarely achieved by US bombers equipped with Norden sights, which might explain why British interest in it quickly waned and it was rejected when finally offered late in the war.
ALL US bombers were supposed to be precision bombing, at least as far as the public back home was concerned, yet their results were often worse than those achieved by the RAF's area raids at night. In the last quarter of 1944, for bombs dropped by the USAAF in Europe under conditions of good visibility (as the RAF enjoyed for 'Catechism' ) the figures show that B-17s dropped 13.1% and B-24s a mere 8.8% within 500 feet/ 166 yards of the aiming point with the Norden sight.
The main draw back of the SABs when compared with the Mk XIV (though not the Norden) was the tactical limitations imposed by a long, straight and level bomb run. The Mk XIV required a ten second run and could be used in a climb or glide, allowing a greater degree of tactical freedom, though Bomber Command still attempted to limit evasive manoeuvres. The SABS was also complicated and difficult to manufacture and required skilled maintenance, certainly when compared with the Mk XIV.
Cheers
Steve
The Norden couldn't be measurably less accurate than the SABS 2.
In principle the SABS 2 worked the same way and didn't add any computational refinements: Both sights were gyrostabilised, calculated the true ground speed of the aircraft by tracking an object near the target or the target itself. This was done by the bombardier setting the speed of variable speed electric motors that moved the optics till the target remained steady in the cross hairs.. The motion of the optics was linearised to account for the bombsights angle of view and altitude hence the speed of the motors was proportional to the ground speed.
They used this true speed over ground to calculate offsets to compensate for target motion and or winds.
What the SABS Bomb sight had to achieve in bombing the Tirpitz was +/- 0.28 (0.56) degrees accuracy for the beam and +/- 2.0 (4.0) degree for the length of the Bismarck which isn't very high.
Neither sight had Ballistic data for the bomb. The bombardier used tables and dialled in bomb fall time, bomb trail error (compared to a bomb dropped in vacuum) and air speed.
Probably the most impressive level bombing successes was achieved by the lofte 7D carried on three Fw 200 Condors of III/KG40 who in July 1943 attacked Convoy Faith. Each of the 3 Fw 200 dropped 4 250kg bombs and achieved 4 hits on 3 moving ships sinking 2 and burning out one. The attacks were carried out from 15000 ft under fire from the escorts.
I have no doubt the Norden could achieve almost as well.
Nor can I imagine the Norden and SABS 2 were ever compared apples to apples. The Americans bombed deep inland targets that could be hard to identify and only the lead bomber of the widely spread formation aimed. 617 squadron however had a clearly identifiable target in Tirpitz. No mistakes. However 617 bombing accuracy was terrible the month before under operation obviate due to the German fog cloud.
The Tallboy was a very precisely made and large dense supersonic armour piercing bomb resistant to deviations due to wind gusts that weighed over 10000lbs. The USAF was dropping 1000lb light case GP bombs with a blunt nose. The smaller slower falling bomb would have more manufacturing variation and be more effected by wind disturbances. The USAAF used CEP because the method of evaluation was to draw a circle of radius of the typical CEP with a compass around the aim point, count the total number of craters inside and if there wasn't 50% to slightly enlarge the circle and add in the additional craters till 50% of the total bombs were counted. If you want mean radial errors you have to individually measure distances from the crater to the aim point. Apart From being slow to evaluate it didn't make sense with formation drops nor provide an idea of bomb density. Most US CEP must have been form formation drops that covered hundreds of yards. In addition B-24/B-17 bombed from higher altitudes and the dispersion increases.
The MK 14 continuously told the bombardier where the bombs would fall as the aircraft manoeuvred allowing the crew to continuously adjust the flight path till the cross hairs were on target. It more or less worked like the Luftwaffe Stuvi 5B with BZA dive and slide bombing sight though it was the pilot the operated to Stuvi.
The SABS, Norden and Lofte 7 guided the aircraft to the release point upon which the cross hairs were placed.
I don't believe the SABS was superior to the Norden. In accuracy The Norden could have a supplementary device added that alllowed bombing during the climb or dive.
The German Lofte 7 was highly regarded. It was easy to maintaining durable and so tended to work and its optics could track the target much earlier than the Norden.