NavList:

Given what is happening in the Red Sea, it might be time to revisit those formulae for plotting great circles. Shipping movements through the Suez Canal are being disrupted by terrorist activity in the Red Sea. At least 3 oil shippers have already announced that they are re-routing tankers around southern Africa instead. 

Away from the textbook, great circle sailings happen very rarely. See the current Ocean Globe race gps tracking as an example. Across the Indian Ocean, only one yacht appeared to have followed a GC course to NZ, partly due to the need to stay north of virtual ice clearing marks. A passage needs to be very long to make the difference between GC and mercator meaningful. Weather conditions and other limits are usually the more important considerations.

However, it can still be useful to have a reasonably accurate knowledge of a GC route, not to steer one's own passage but rather to know where the shipping lanes are. The ships will follow GC courses where possible and if shipping is forced to travel further distances across oceans to avoid the Red Sea, this knowledge will become more important for sailors.