In the old days...
... the RN had a procedure when the visibility was pants/scoshie/not very good, for helos returning to Mother. Normally used when the ship entered a fog bank, for example, as the helo was on finals. It was called Low Visibility Approach. This involved the aircraft engineers grabbing hold of an item called 'Smoke and Flame Float' (SFF). When the Helo Controller said so, a SFF was launched over the stern. It was every 30 seconds or so? The helo was radar vectored dead astern of Mother and flew at 50 feet radalt IMC (?) and Vmin until the crew picked up the flares, which lasted for 5 minutes or so, followed them in, and then gained visual with Mother and landed. Sorry, no pics. Too busy trying to find Mother!