Classic British Flight Sim

For Transatlantic/long over-sea navigation, in the days before Delco Carousel INS and thereafter, I understand airliners used 1) LORAN - a system I have never quite been able to have explained clearly plus, 2) DOPPLER Radar. For the latter, I understand the navigator got a return on a graded (?) small screen and then, with tables and a flight computer (the slide rule type) could work out drift quite accurately.
Perhaps some of the 'senior' pilots on here could explain how these two systems worked in more detail.
Thanks in advance.

I remember using Loran C on Oil Tankers. Its is a US based system similar to DECCA which was used in Europe. The system works on time difference of radio signal pulses and in the bad old days positions were found on charts overlaid with a printed numbered lattice of intersectling parabolic lines. The readout from each transmitter in the area was shown on a digital display which was then marked on the corresponding lattice. I understand that nowadays the equipment will give a direct lat & long output. See this site for more details http://www.uscg.mil/d17/lorsta/tok/Loran-C.htm

Hope that helps.
Steve M