Dear all,

Thankyou for your replies to my question, they are most informative. I find it interesting that despite being such advanced 'machines', U-Boats still relied on techniques first layed out by the Babylonians.

Do you think it was possible to take a sighting via the periscope? Obviously a sextant would not have been practicable, but could a sextant have been built into the optics of the periscope? I dont see why it would have been impossible, though it might reduce the choice of stars. In the right latitude a noon-sight might have been possible?

It is interesting to note that U-Boat navigation must have been quite reliable, because wolf-pack tactics relied on U-Boats knowing where they were. If a U-Boat was a little way-out when it sighted a convoy, and that position was related to a U-Boat that was also slightly adrift, and that second U-Boat was unable to take an accurate sighting whilst moving to position of the first U-Boat, the second U-Boats could easily never find the convoy. I suppose working in the U-Boats favour is the fact that some of these convoys were huge and covered quite a lot of ocean, on the other hand the Atlantic is a big place.

Thanks again for your posts,

Andrew