sure, using the sonar man to get a rough speed estimate significantly reduces the range of possible aobs.
But in fact, greyrider, all due respect, this is broadly speaking a rehash (and a limited one at that) of what i was writing about 3 or 4 years ago.
And in any case, the USN more or less already solved the problem from the other way round(for finding speed, when AOB is known, and in reality being able to eyeball AOB is a skill that is more or less assumed to come with practice)
OK you can do it without markings on the map, whereas the thing i wrote about several years ago used markings to help the procedure.
This is the article i wrote several years ago, but it took advantage of the speed omnimeter side of the ISWAS tool:
http://www.subsim.com/radioroom/showthread.php?t=115587
it was rewritten better subsequently, can be downloaded from my ff, but in fact someone else rewrote it again even better.
But a better idea is to read the original USN document detailing the use of the ISWAS, written between the wars, when such techniqes were a staple of submarine attack doctrine, before PKs and radar appeared. Has the advantage over conventional plotting in that the operation occurs while making a normal approach.
http://www.hnsa.org/doc/attackfinder/index.htm
Still, if you want to popularise the method, that's cool with me.