Never used them myself, but I thought the sight was for unguided rockets - cue the story about K** G***s (my next-door neighbour in Hants when we were - allegedly - growing-up) and the Mansion in Malta. I'm sure someone ex-RN will be along shortly to furnish us with the details.
(John, the de-cluttering bit of SF8 is iSRD, just under the Unsharp Mask control in the sidebar on the left. You can tweak the sensitivity of the detection to get the right amount of 'fuzz' removal without loss of original image quality... but you probably knew all this already)