The S&R world has changed markedly since my time. Our equipment was extremely limited , (the only non-military aid was the Automan oxygen set) so the Mk1 eyeball was the primary seach device. The method of keeping them in good working order was the daily 'beach bumble' - a 'patrol' of our coastal patch with a mental note of potential trouble spots, or possible Wx related issues. I suspect that reliance on such things as thermal imaging, (plus the ever-present bean-counters) will have dispensed with such routines. Without good quality eyes, the Station Commander of a large overseas base, in a light blue dinghy without sails or oars, at dusk, would probably have continued his uncontrolled journey in the Med! His gratitude, on being spotted and recovered, was not evident!