WW2 navaids....
.....were not all that great. John Cruickshank VC once told me that he had been tasked into a "box" SE of Iceland for a very long surveillance mission in his Catalina. The cloud base was was low and very thick. No sun, no stars when it got dark, all done on DR when the forecasts were a tad "variable". At off task time they set heading for Sullom Voe in Shetland and after a long transit made landfall on the island of Benbecula. Buggah!! It was now another 4 hrs coast crawling to back to SV. And errors of that magnitude were not uncommon.
This tale was triggered after his first trip in a Nimrod where, back in dispersal the baby nav was claiming that the nav system was a tad out - the error being inside the wingspan of the aircraft after 6 hours.
The Ancient Mariner