A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2020 Sep 24, 09:46 -0700
I studied for O levels in 1960 in fps units. By A levels in 1962, I was studying in cgs units, and soon after it changed to mks units. However, upon arriving at Imperial to study Aero Eng, I was introduced to the wonderful ‘slug’, that mass which is accelerated at 1 ft/s2 when a force of one pound force (lbf) is exerted upon it. Now that was a unit to marvel at. We were always taught that it didn’t really matter which units you used so long as you followed values with the appropriate unit. Therefore, it came as surprise to find when teaching tech drawing, amongst other things, between 82 and 94 that in the UK by then, so long as you used mm in your drawings, you didn’t need to add the units.
In my opinion, the oddest time to change units was 1st April 1945, when Bomber Command Navigators changed from mph to knots with all the confusion that must have caused. They really did; I’ve checked a chap’s logs and charts from March and April 1945. Whilst some might think the date was appropriate, one would have thought they would have postponed the change for a couple of months until the war in Europe was over. DaveP