Why Did the He 177 Fail?

[Juha]

Steep fjord walls do absolutely nothing to protect from level bombers, they did however block the Tirpitz's own warning radar and FLAK.

Tirpitz wasn't achored in steep walled fjord, the area around was rather flat for Northern Norway next to Tromso town, look photos, maps or Google Earth. In fact that was intentional because Germans had chosen a shallow anchorage for Tirpitz. The far away mountains were limiting the radar but that had no effect on AA because other radars and observation posts gave ample warning and RAF was using same approaching route than 2 weeks previously. So AA was put on preliminary alert almost 1½ hour before the attack and flak alarm was sounded an hour before the attack. Tirpitz went to action stations 36 minutes before its 15" guns open fire when the first bombers were 21 km away shooting markedly too low, so much on the blocking effect of the mountains.

The Tirpitz was exceptionally poorly protected, the kriegsmarine reports of the time are emphatic that much more shore based FLAK was needed, in fact I can't even see any FLAK on the photo recon.

There were 2 flak ships nearby, plus one medium and one large size vessel which also put up AA fire and british photo interpreters found 12 heavy and 20 light AA guns on land near Tirpitz before the first attack on 28 Oct, not very much but better than nothing and Germans might have deploy more during the 2 weeks between the attacks.

The Luftwaffe was exhausted: extremely thinly spread, short on fuel, hadn't been told that the Tirpitz had been moved to a new Fjord, whose defences hadn't been built up. She was sunk in November 1944 as the Luftwaffe was collapsing and was short of men and machines.

Most of the III./JG 5 was at Bardufoss, 70 km south, Tirpitz had been at same place almost a month, had suffered one daytime air attack, ruined by cloudcover, 2 weeks earlier. III./JG 5 had fuel to take off on 12 Nov but because of delays missed the Lancs. So we had a big battleship achored off the nearest town, 70 km away, already a month, which had already suffered one air attack and the fighter boys didn't have a clue?

The bomb aiming was not remarkable or exceptional from the height it was conducted considering that several dozen tall boys were dropped. It was well within the capability of any competent bomb aimer from the Luftwaffe, USAAF, RAF using a Lotfe 7, Norden or SABS2. Assuming bombing from 14000ft hitting a ship with a 100ft beam represent an error of of 0.7%. An 800ft length would be impossible to miss.

LOL, so all the RAF, LW, USAAF, IJAAF and IJNAF bomb aimers who mostly missed their achored targets were incompetent? IIRC during the initial phase of the Pearl Harbor attack, the 49 Kates dropping 800 kg AP bombs almost training conditions and lower level got 7 - 8 hits (4 on Arizona, 2 on Tennessee and 1 or 2 on Maryland, not sure on the size of the second bomb that hit Maryland) and those were pre-war trained IJNAF regulars, probably as good as you ever got during the WWII. But you are right that the bombing of 9 Sqn wasn't satisfactory and so the SASO of the 5 Group wanted 'a thorough investigation' on that.

With nearly three dozen bombs dropped its surprising they didn't get more hits suggesting the heavy FLAK distracted the RAF crews somewhat.

How surprising, look my info on Fritz-X accuracy testing vs real attacks in my message on the Ju 388 thread.

Statistically it's the equal of dropping 36 marbles onto a 1cm wide model battleship from waist high. You are bound to get a hit.

Maybe the real world bombing is a bit more difficult, at it seems to be in the light of history.

No ones heavy AAA worked well at that altitude. The USN Reckoned that 80% of the aircraft it shot down were defended by 40mm bofors and 20mm oerlikon.

The main aim of the heavy AA is to force bombers higher and hinder bombers, or at least it should be.

 

[stona]

There seems to be a lack of understanding of bombing accuracy.

In the period June-August 1944, shortly before the attack on Tirpitz, 617 Squadron was achieving an average radial error from 17,000ft (just above the level of the Tirpitz attack) of 170 yards (510 ft). This in fact makes it statistically remarkable that they could hit a target measuring 824 ft by 118 ft with so few bombs.

Cheers

Steve

 

[Shortround6]

The land heavy AA was what? 88mm guns? 16000 ft was about as good as it was going to get for them. Short time of flight compared to higher altitudes. Angle for tracking not bad compared to lower altitudes, decent engament time (rounds fired while bombers are in range).

Land based and even ship based AA was not moving so effectiveness should be better than a moving ship in a seaway.

The marble analogy doesn't work well not only because it is chest high, not waist, but it doesn't allow for the time of flight/drop problem. How many seconds from release to impact? A 100 ft error in bombing altitude (0.625%) can throw the impact off. Along with other small errors.

 

[GrauGeist]

Might also point out that standing over a scale model and dropping marbles is a flawed analogy.

As SR suggested, try it from chest high - while walking

 

[Koopernic]

How surprising, look my info on Fritz-X accuracy testing vs real attacks in my message on the Ju 388 thread.

.

I have Bollinger's book on my kindle. Unsurprisingly you seem to have found (what page I can't find) the worst passible unit performance with the worst possible performance.

Bollinger also gives the success rate of the Hs 293 at 30% (page 172) which could be raised to 50% if a charitable interpretation that included near misses that caused light damage.

As far as the Fritz-X is concerned it had its greatest success by 1943 and wasn't used much for nearly a year. When it was it was next used it was over allied invasion beaches at night or in the face of stiff fighter opposition and these latter efforts drag down the result.

At this time the He 177 units were suffering a minimum of 20% monthly losses and often as high as 50%. Earlier attacks by KG40 did so with strong opposition from cruisers but generally no air opposition they also used the reliable Do 217.

Tirpitz wasn't achored in steep walled fjord, the area around was rather flat for Northern Norway next to Tromso town, look photos

The Fjord was high enough to prevent early enough detection or the raiders and allow organisation of interceptors and the smokescreen while RAF planners were able to make use of the difficult terrain to minimise what radar warning time there was.

Might also point out that standing over a scale model and dropping marbles is a flawed analogy.

As SR suggested, try it from chest high - while walking

It's entirely apt, the error, in artillery terms is 7.375 mil (parts out of 1000). Good artillery operating over similar ranges would achieve 1 mil.

So long as the bomb sight and its optics is all precision made and aligned to less than 1/1000, the bomb precisely machined so that it conforms to the tables prepared earlier then the bomb will be accurate. A rifle or artillery shell has to be made with similar precision and its propellant charge also 'weighed' with precision. The fall time makes little difference except in the area of direct impingement of cross wind on the bomb. The Bombsight has already compensated for the direct drift of the aircraft before release, the major source of error. A little unexpected side wind or head wind on the way down is not going to move a dense 10,000lb pound steel bomb like a tallboy of target much over a 15-20 second fall.

If you want to fuss its equivalent of dropping a precisely made steel ball bearing of 1mm diameter from chest onto a 8cm by 12mm model Tirpitz high using a computer to open a solenoid release with the computer able to access the exact height and speed.

There seems to be a lack of understanding of bombing accuracy.

In the period June-August 1944, shortly before the attack on Tirpitz, 617 Squadron was achieving an average radial error from 17,000ft (just above the level of the Tirpitz attack) of 170 yards (510 ft). This in fact makes it statistically remarkable that they could hit a target measuring 824 ft by 118 ft with so few bombs.

Cheers

Steve

Under what precise circumstances, using armour piercing bombs or GP, in combat, at night and what target? A ships is clearly identifiable as being the target. The GEE-H (which was more or less Oboe) in the guise of its American clone micro-h when measured in use by US the Operations Research had error's measured in miles rather than the 50 meters it was capable of. This is a blind bombing system that should have eliminate all possible visual errors yet they still failed to follow the instructions. Was it bad targeting, unwieldy formations, being distracted by FLAK. Well trained crews following a well rehearsed and double checked plan used the kit properly and attacked the correct target.

 

[Juha]

I have Bollinger's book on my kindle. Unsurprisingly you seem to have found (what page I can't find) the worst passible unit performance with the worst possible performance.

Difficult to see on what you are complaining, III./KG 100 was the Fritz-X unit and I gave the the results of it. That covers both the Do 217 and He 177 periods. And you first put forward the accuracy of Fritz-X on that thread but forgot to mention that that was the accuracy during the tests not that of combat situation. As usual the first ones were considerable better than the latter. The Graph is 12.1 and is it on the page 173 in the printed book. IMHO you should also read the text right after Graph 12.4 that might bring some reality to your appraisal of the effectiveness of the guided weapons of the WWII. They were a step forward but not yet a gigantic leap forward.

The Fjord was high enough to prevent early enough detection or the raiders and allow organisation of interceptors and the smokescreen while RAF planners were able to make use of the difficult terrain to minimise what radar warning time there was.

Nix, see my previous message, the times were from the report of the Tirpitz' senior AA defence officer. The lancs were seen far away from Tirpitz and there were good early warning messages from other observation post. Something went badly wrong on the German side and it wasn't surprise that the military tribunal passed out several prison sentences.

 

[Juha]

Because it seem that some are too lazy to dig out the info on the terrain around Trömsö here is a link to a film filmed during the attack, flak bursts can also be seen.
Daylight Attack On 'tirpitz' - British Pathé

It also shows one reason why 9 Sqn, which bombed after 617, had difficulties in bomb accuracy.

 

[pbehn]

Hitting a ship with a single bomb was a fantastic achievement in accuracy. Bearing in mind bombs dropped from the same height by whole fleets of bombers were known to miss the given target completely by a wide margin I cannot see how a counter argument is put forward. Not only was the Tirpitz hit but various submarine pens bridges and the V3 launch sites were also taken out. It may annoy some that the Lancaster dropping Tall Boys and Grand slams were extremely accurate and destructive but they must live with their annoyance it is a historical fact and it wasnt chance. In three missions against the Tirpitz, operations paravane obviate and catechism Tirpitz was damaged each time. Additionally the Lutzow was crippled by a near miss and settled on the bottom.

 

[kool kitty89]

In the period June-August 1944, shortly before the attack on Tirpitz, 617 Squadron was achieving an average radial error from 17,000ft (just above the level of the Tirpitz attack) of 170 yards (510 ft). This in fact makes it statistically remarkable that they could hit a target measuring 824 ft by 118 ft with so few bombs.

Is there any information on accuracy specific to tall boy bombing? (or tall boy and grand slam?) Regardless of the other variables in the case of the Tripitz, the ballistics of those bombs should have made for significantly lower errors. (in fact, I wonder if the consistent ballistics of those bombs actually gave them an edge in precision over the guided bombs used during the war)

 

[Koopernic]

Bomb errors given in circular error probable are a gross simplification of what actually happens. Bomb fall patterns, naval shell fall patterns are far more likely to be shaped like an elongated oval shape, very elongated by 4:1. They may even be cross shaped.

The CEP appears only useful for gross statistical assessments of weapons fired from near point blank range. I've often seen Luftwaffe assessments in terms of a 60% confidence or defined as a square or rectangle. IE 50% of bombs fell within this dimension of the x ordinate and 50% within y ordinate, the kind of information you need for planning an attack on irregular shaped targets such as ships, bridges or tanks rather than calculating how much misery has been created in area targets below. In terms of the November 1944 RAF raid that hit Tirpitz with 1-2 tall boys of 29 dropped and 31 carried the run ups were so as to line up the bomb fall pattern with the highly oval shape of the Tirpitz.

Converted into a circle Tirpitz was a target nearly 100m diameter.

A basics junior (lower high school) high school physics course on error budgets should convince anyone of the high basic accuracy of these sights. There are challenges such as making sure the bomb sight levels itself to within better than say 0.1 degrees, that the basic computing mechanism that calculates speed does not degrade this and the the mechanism that automatically releases the bomb is also precise. Even the speed of the bomb release mechanism must be consistent and taken into account.

These sorts of accuracies were achievable, the USAAF based its entire doctrine around the results they had achieved in tests of the Norden, these were not faked or fudged.

The actual stress of combat introduces new realities and factors that degrade this but experience, good drill, planning, experience and air superiority could clearly restore this.

RAF aircraft dropping tallboys were effectively operating in conditions of air superiority, they were seldom intercepted or were well protected by escorts by the time the tallboys had been developed.

I imagine the tallboys aero ballistic properties were measured full scale in a wind tunnel at a variety of air pressures and velocities and that bomb trail errors were tabulated spreadsheet style by the ladies. I suspect the grandslam shared the exact shape and could use the same data as Reynolds effects would be minimal but would also fit a wind tunnel nicely.

It's worth noting that great care could have been taken with the manufacture of tallboys thus assuring tables conform with the actual bombs produced whereas the finest bomb aiming in the world would be thrown of by a batch of 500lb bombs in which the fins were canted in slightly inconsistent ways and whose weight varied.

A bomb throwing machine seems unlikely.

The better bomb sights took the human factor out, automating bomb release. The USAAF even used radio command to sequence the pattern of the bomb release across a formation from command of a lead bomber.

I have a high regard for what humans can do in "aiming" our species evolved with fire and using ballistic weapons for over 500,000 years. One only needs to see what a genetically talented world class spin bowler can do after 10 years practice. However these advanced sights took the u or elastic level,of trying out as well as reducing eventing to a precise mechanised calculation.

I expect the bombers all did individual runs but they may have use groups of smaller formations to get a pattern.

The probability of a hit reduces with the power of 5 with range a doubling of altitude reduces pk by 32.

 

[GrauGeist]

Hitting a ship with a single bomb was a fantastic achievement in accuracy. Bearing in mind bombs dropped from the same height by whole fleets of bombers were known to miss the given target completely by a wide margin I cannot see how a counter argument is put forward. Not only was the Tirpitz hit but various submarine pens bridges and the V3 launch sites were also taken out. It may annoy some that the Lancaster dropping Tall Boys and Grand slams were extremely accurate and destructive but they must live with their annoyance it is a historical fact and it wasnt chance. In three missions against the Tirpitz, operations paravane obviate and catechism Tirpitz was damaged each time. Additionally the Lutzow was crippled by a near miss and settled on the bottom.

Well, if the mission (choose whichever attempt you like) was so successful, why did it take so many attempts to take the Tirpitz out?

The terrain surrounding the Tirpitz added a high degree of difficulty whereas the mission against the dam offered a much different formula and circumstances for success.

And from my vantage point, I can't see anyone belittling the Lancaster missions or their acheivements.

 

[parsifal]

I am surprised that there is so much divergence of opinion on this Tirpitz thing

 

[Juha]

Well, if the mission (choose whichever attempt you like) was so successful, why did it take so many attempts to take the Tirpitz out?

Simply because of smoke and/or clouds. It is difficult to hit a pinpoint target which one could not see. During 29 Oct 44 raid Lancs were only a few minutes late, seeing Tirpitz during the run in but just before releasing point clouds from the west drifted over Tirpitz spoiling the attack. The problem was that it was late autumn and so the weather was what it tended to be and the Artic Night was fast approaching so RAF wasn't in position to wait a long spell of clear weather.

The terrain surrounding the Tirpitz added a high degree of difficulty whereas the mission against the dam offered a much different formula and circumstances for success.

That had profounding effect on 1942 raids and maybe also on the Alta raid because there the fjord there was rather short. But not at Tromsö because Lancs attacked along a very long fjord so they saw the target tens of miles away (and were seen). The chosen attack route allowed very early target acquaintance but means that the bombers passed the Bardufoss airbase, where 2 full Staffeln of III./JG 5 were based, by only some 15 - 20 km.

 

[stona]

I am surprised that there is so much divergence of opinion on this Tirpitz thing

The difference is really that some seem to think that with the SABS sight hitting a battleship, even stationary, was a simple thing. The SABS sight was not some miraculous instrument, in fact at the same time as 617 Sqn was achieving an average radial error of 170 yards (later improved to 125 yards), 9 Sqn was achieving an error of 195 yards with the Mk XIV sight. The difference was just 25 yards, not as great as some imagine.

I think that hitting a stationary battleship was a remarkable achievement, even given the better sight, and was the result of much time on the practice range. The Tirpitz attackers may have been operating in an era of allied air superiority but they still flew at an altitude above some of the more deadly forms of flak. The higher you fly the less accurately you bomb. The 8th AF considered this one of the most successful aspects of German flak defences.

Anybody know how many large warships, with the exception of Tirpitz, were hit by level bombers flying at 15,000 ft or above in all theatres during WW2?

Cheers

Steve

 

[Juha]

For starters RAF: BBs Scharnhorst (this is arguable, Merrick's By Day By Night says that Halis bombed from 15,000ft but Garzke, William H.; Dulin, Robert O. (1985). Battleships: Axis and Neutral Battleships in World War II says from 10,000 to 12,000 ft misidentifying the bombers as RAF B-17s and B-24s, so info is probably from a German source. But this was an exeptional feat because Halis were under heavy AA fire and numerous fighters were attacking them during the bombing. They got 3 1000lb AP hits, which all went through Sch. without exploding and two 500 lb HE hits with exploded on armoured deck. 15 Halis made the attack, one was probably shot down before bombing, 4 during the return trip. La Pallice on 24 Jul 41), Gneisenau; Pocket BBs Admiral Scheer, Lützow/Deutschland, CAs Prinz Eugen and Admiral Hipper. On 14 December 1940, a British air raid on Naples damaged Pola. Two bombs hit the ship, both amidships on the port side. The hits damaged three of the ship's boilers and caused significant flooding and a significant list to port. Pola was drydocked on 16 December for repair work that lasted until 7 February 1941. Probably by 148 Sqn Wellington ICs which made 3 attacks on Naples in December, but I'm not sure, there is surprisingly little info on this attack even if it and other British air attacks on Southern Italian ports forced the Italian fleet to move its heavy ships to Sardinia, so I have no info on the bombing altitude.

USAAF: B-17s hit both Vittorio Veneto and Roma, B-24s Littorio, one hit on the No. 1 turret, turret remained operational but this was a rare hit on a BB under way in the open sea. The bombing altitude was 12,800m according to Garzke and Dulin, but that is clearly an overstatement. IJNAF Mitsubishi Nells also got one bomb hit on both HMS Repulse and HMS Prince of Wales in Dec 41 but they bombed from around 3,000 - 3,500 m. IJN CA Myoko was hit by the B-17Ds from 19th BG bombing from 7,500 m on 4 Jan 42. On 29 July 1945 IJN CA Aoba was hit by at least three 500-lb bombs that struck across the stern abaft No. 3 turret during a high-level attack by B-24s of the 7th AF

LW: BBs Warspite, Roma, Italia/Littorio hit by Fritz-Xs dropped by III./KG 100. LW used sometimes dive-bombing Ju 88s alongside level-bombing He 111s when the latter made anti-shipping attacks making it difficult to say who made the hits, e.g. during the attack on Scapa on 16 March 40 CA HMS Norfolk was hit but according to de Zeng IV, Henry L. Stankey, Douglas G. with Creek, Eddie J. (2007). Bomber Units of the Luftwaffe 1933-1945: A Reference Source. Volume 1 Ju 88As from I./KG 30 hit Norfolk and He 111s from I./KG 26 hit a cruiser, but because Norfolk was the only cruiser hit that doesn't clear the situation. Shores, Christopher with Foreman, John, Ehrengardt, Christian-Jacques, Weiss, Heinrich and Olsen, Bjorn (1991). Fledgling Eagles only says that both formations bombed and Norfolk was damaged. From what I remember, most RN cruisers hit by bombs were hit by dive-bombers.

IJNAF: On 4 Feb 1942 Mitsubishi G3M Nells from 1st Ku got one hit on the CA USS Houston which disabled
the No. 3 turret of the cruiser. Bombing height was circa 5,000 m.


I'm sure that there were some other cases.

 

[Juha]

Yeah, I originally thought of doing that, but then I still don't have its depth. The reason why I want it in the first place is because I'm trying to compare it to that of the He 277.

Didn't I give the outer depth (from the level of the fuselage floor to the outer surface of the bottom of the bomb bay doors?

 

[SpicyJuan11]

Didn't I give the outer depth (from the level of the fuselage floor to the outer surface of the bottom of the bomb bay doors?

Oh, yes you did, sorry

 

[Elmas]

Incrociatore Trieste sunk by bombs, April 10th 1943.

La Fine del Trieste e Gorizia

 

[GrauGeist]

Here's the HIJMS Hiryu under attack by B-17s during the Battle of Midway:

Also, during the First Naval Battle of Guadalcanal, the HIJMS Hiei came under attack by B-17s with no hits. It was a combination of attacks by torpoedoplanes, divebombers and naval gunfire that sank her.

 

[Koopernic]

The difference is really that some seem to think that with the SABS sight hitting a battleship, even stationary, was a simple thing. The SABS sight was not some miraculous instrument, in fact at the same time as 617 Sqn was achieving an average radial error of 170 yards (later improved to 125 yards), 9 Sqn was achieving an error of 195 yards with the Mk XIV sight. The difference was just 25 yards, not as great as some imagine.

I think that hitting a stationary battleship was a remarkable achievement, even given the better sight, and was the result of much time on the practice range. The Tirpitz attackers may have been operating in an era of allied air superiority but they still flew at an altitude above some of the more deadly forms of flak. The higher you fly the less accurately you bomb. The 8th AF considered this one of the most successful aspects of German flak defences.

Anybody know how many large warships, with the exception of Tirpitz, were hit by level bombers flying at 15,000 ft or above in all theatres during WW2?

Cheers

Steve

The distribution of bombs for a typical CEP (circular area probable) is approximately as follows.
A/ within one radius of the CEP 50%
B/ outside of one radius but within two 43%
C/ outside two radii 7%

Within one radius of the CEP the distribution of bombs in terms of area is approximately even though there is a some clustering towards the centre.

The distribution is Rayleigh (two dimensional Gaussian) ie the normal curve. Form a statistical mathematical point of view it would have been nicer for the CEP to be defined as the radius which contains 63% of hits. I've seen that the Germans at least defined the accuracy of their FLAK radars in this way.

Accuracy degrades as per a cube law though I've heard it claimed that the probability of a hit in naval artillery is according to a power of 5 law. I am not convinced, I can see how a square law applies to ballistic fall of an side ways deviation of a projectile which accelerates and thus integrates according to a square law.

Hence a 10% increase in bombing altitude would increase CEP by 33% or 50% depending on which law you believe is the truth and apply.

The Lancasters that attacked the Tirpitz bombed from between 12500ft and 16000ft. The former is likely what achieved the hits.

If we assume 617 squadron achieved 170yards/150meter CEP at 17000ft they would achieve significantly better at 16000ft and dramatically better at 12000ft.

But take the example of 32 bombs with a CEP of 170yard/150meters, 617's assumed CEP at 17000ft, and noting that each 50% reduction in radius would have 25% of the bombs.
A 16 bombs would be within 150m
B 4 bombs within 75m
C 1 bomb within 37.5m. Suggesting a high probability of a hit, greater than 50%, since the radius with an area equal to Tirpitz was around 45m.

These radii could be reduced about 6.5% for 16000ft as compared to 17000ft.

Using the cube law bombing at 12500ft as opposed to 17000ft should double accuracy but using a conservative linear approximation reduce CEP 12500ft/17000ft x 170yards = 125yards/112meters.

Lets run our calculation again, for 32 bombs dropped from 12500ft with a CEP of 112 meters.
A/ 16 bombs would fall within 112 meters
B/ 4 bombs would fall within 56 meters
C/ 1 bomb would fall within 27 meters, the Tirpitz can be assumed to have an area with a radius of 45 meters on the basis of its area.

If we consider the slight clustering effect and that the improvement between 17000ft and 12500ft was probably due to a cube law then the odds look quite good.

It's worth noting that the raid was a repeat of another 32 bomber raid conducted in October 1944 in the same fjord so in effect about 60 bombs were dropped.

*************

Early bombsights simply were set at an angle according to tables and didn't use optics but use a tongue and V similar to a traditional rifle, the RAF initially preferred this for night use. They contained elementary mechanical elements to help the course to be set in the presence of estimated wind etc. If the aircraft was jostled or its angle of attack varied then the bombsight could go off by a few degrees that could equal hundreds of meters.

The first major improvement in bombsights seems to have been the introduction of gyroscopically stabilised optics. Quite oddly it seems the RAF tried a computing bombsight without a gyroscopically levelled platform in the ABS I and so did the Luftwaffe with the Lotfe 7A, it would seem pointless to carry out accurate calculations from such an unstable datum. Once stabilised, using a pendulum that was averaged out by gyroscopes there was a stable datum.

The difference between the Mk.14 bombsight and the SABS IIB was that the Mk.14 simply told the bomb aimer/pilot where the bombs were going to land, even in a slight dive and while manoeuvring, the sight also helped the bomb aimer set a course to run over the target. The wind drift or estimated target motion had to be estimated and manually entered so it was no good against a moving ship if bomb fall time was a factor or stiff winds. Meteorological aircraft and master bombers probably provided this information.

The SABS IIB was similar to the Norden and Lotfe 7. It added a function in which the ground or targets relative motion could be tracked. Effectively a mechanism (tachograph ?) tracked a fixed spot on the ground on the basis of altitude of the aircraft and target as well as the aircrafts true air speed.

The bombardier then adjusted some variable speed drives and this adjustment is in fact the wind drift (or in the case of a moving ship its velocity vector). The sight now put out actual ground speed and the magnitude of the cross, head wind.

We know the bomb trail, we know how long it will take to hit the 'ground' and it is now possible to come up with an aiming solution.

Navies had been doing it for decades (Dreyer tables, the more advanced Pollen system) and it had been done in FLAK predictors.

As far as attacking a ship is concerned it would make little difference if it was stationary or moving to a wind correct bombsight. So long as it moved in a straight line as merchant ships did.