Paper charts are a rare sight, upon Stargazer's chart table. But, in some circumstances, they possess capabilities which their digital successors do not.
One such situation is when determining the shortest course to steer, for a cross-tide passage affected by multiple tidal cycles. Drawing out a 'tidal triangle' (net tidal set along the bottom, direct line to destination one side, course to steer the other) reveals the rhumb line (shortest) course.
From that, a theoretical course over the ground may then be plotted. Which indicates where Stargazer might end up, at the end of each tidal cycle. Those three plots reveal: that we are likely to be in danger of encroaching on the Fecamp windfarm, at the end of the first east-going tide; before being set eight miles west, to the tip of the mid-Channel TSS (Traffic Seperation System), during the west-going run; and then carried back, to pass Beachy Head to port, by the end of the second east-going tide.
All grist to the real world pilotage mill for Stargazer. Now that the, all important, PaF stamp has been secured in her skipper's passport.
No comments:
Post a Comment