My father got an 18 metre 1970s-vintage yacht in 1994 or thereabouts. I remember learning to plot accurate fixes using LORAN signals and hyperbolic TD lines. Ge

My father got an 18 metre 1970s-vintage yacht in 1994 or thereabouts. I remember learning to plot accurate fixes using LORAN signals and hyperbolic TD lines. Getting good at that and coming up with (what I thought) were really clever transformations between Euclidean maps with hyperbolic curves to straight lines on a curved surface served me very well (at least in terms of intuition) when later I learnt of non-Euclidean geometries. (I also remember looking through ancient manuals and building up an intuition for troubleshooting and fixing a thermionic valve-based RADAR, at least once in high seas with almost zero visibility as howling winds and lashing rain was pushing us towards a rock face. Fun times.)