I remember reciting in school that 5½ yards = one rod, pole or perch. Therefore, it works out that there are 4 of them in a chain.
A fathom is approximately* 6 ft and a chain is 66 ft. That makes approximately 11 fathoms in a chain.
I also remember from school that there are 10 chains to a furlong and 8 furlongs in a mile.
It kinda pisses me off that I still remember all this. The memory cells that store shit like this in my brain could no doubt be put to better use remembering more important stuff.
Who came up with this shit anyway? Why would any sane person use 5½ as a multiplier?
* Some more of my brain cells are occupied remembering from a celestial navigation course I did many years ago that a fathom is 1/1000 of a nautical mile, which up until 1970 was one arc minute of a great circle, or 6076.1 ft. That makes a fathom exactly 6.0761 ft, or about 6'0⅞". I used to work with a bloke who reckoned that at 6' tall, he was exactly one fathom in height. Peing a pedantic git I had to tell him that he was ⅞" short of a fathom.
But that's not the end of the story because in 1970, the British Admiralty re-defined the nautical mile from 6076.1 ft to 6080 ft. But they left the fathom as it was so now there are 1000.642 fathoms in a nautical mile.
Clear as mud, eh? Makes me proud to come from British stock
