Shown here is the Type IXC boat, U-523 with her Focke Achgelis FA-330 Bachstelze (Water Wagtail) rotary-winged kite deployed ready for use.
Powered only by the forward motion of the U-boat, the pilot would ascend to around 500 ft, remaining tethered to the U-boat and in contact by telphone with the bridge. Safe only for use in southern waters where Allied ASW patrols were less active.
