Bomber Command failure at Urft Dam.

[Bill Walker]

H2S in 1944 was not what we would call a precision targeting device today. It allowed Bomber Command to find larger cities, but nothing as small as a single dam. Target markers dropped using H2S often had errors of up to a mile, but at the time that was a big improvement over the errors of tens of miles using purely visual methods early in the war.

It was more a navigation aid than a bomb sight. Postwar refinements allowed developed versions of H2S to be used as a bomb sight, as in the runway bombing in the Falklands.

All the pictures of 617 Lancasters I can find on the web do not show an H2S fairing.