A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Jeremy C
Date: 2022 Jan 1, 12:22 -0800
Flipping plotting sheets is something we do all of the time. When we use the latitude specific plotting sheets (90x series), we routinely flip them over (they are designed that way with the southern hemisphere information in italics). We have only so many, so we flip them over and essentially plot like you suggest. These plotting sheets are secondary to ECDIS at this point, and in less than five-years, we probably won't plot on them at all as the industry and militaries move to double ECDIS navigation systems.
I know in this case the RL/GC distance is minimal, only about 8-10 miles, but that 30 min to an hour for a ship, and about 2 MT of fuel. Given the current economic and political climate between emissions and time, we are expected to take the 8 mile savings. With ECDIS and track-following autopilots, we can actually steer GC paths more accurately now as opposed to converting GC tracks to RL at 5 degrees of Longitude increments like we used to.
I have made several runs around Cape Hope from the Grand Bahamas channel and we typically run GC all the way. However the most dramatic GC run I have made is from just south of Japan to the Panama Canal. It was summer and the weather was great. IIRC it was quite the distance savings. I did the run again last January and it was RL from Japan to east of Hawaii (about 135W) due to weather and then GC to the canal.