Aiming Errors

Photographic evidence also revealed a stark systematic error in aiming; on average aircraft were bombing some 60 yards ahead of the U-boat conning tower. Conventional thought had been that the pilot should aim in advance of the U-boat to allow for forward motion of the submarine as the bombs were falling but evidently this was being overdone. The instruction was therefore changed so that crews began aiming at the conning tower of the U-boat itself. The adoption of this policy was shown to eradicate this systematic error and it is thought that this measure alone increased U-boat sinkings by 50%.

Another improvement was the introduction of a proper bombsight, the Mark III. Previously aiming was done by the pilot using the naked eye. By introducing a proper fixed sight  calibrated for low level bombing it was hoped that accuracy could be greatly improved. The new sight was introduced in large numbers in mid-1943. This improved range accuracy to 43 yards and line to 11 yards. The improvement in range was actually not as large as was first hoped however the improvement in line was unexpected as the Mk III only improved range estimates. The line improvement was due to the fact that bomb aimer now took charge of determing the time of release leaving the pilot free to concentrate on the line. This improvement in aiming meant a steady rise in success towards the end of the war.