Did a pond crossing in a Victor once, (W to E) where all our Nav kit failed. Solar activity wiped out the OMEGA, the sea was so smooth the Doppler fed GPI wouldn't work, we were out of range of fixes for the H2S/NBC, the available NDBs and TACANs were too far away, and the audio was so poor on the ADF we couldn't even manage a Consol count. So the SODCAT representative got the sextant out and we managed to coast in 30 miles off track. I was impressed, but Shanwick weren't and we got violated!
Incidentally, this was when pond crossings required two long range Nav systems. OMEGA counted as one, the Navigator the other. One fed by electricity, the other by pies!