It's actually a pretty easy system. All you have to remember is 39 and 25.4. For linear that is. A 40 is how you measure beer.
As Tim states, the Mendenhall Bill was passed in 1893. All the years since have seen many, many mandates and bills introduced and SI committees formed to only partial avail (dual labeling and some departments). There were conferences in the 60's, 70's, 80's, 90's and finally a petition with a whopping 25,000 signatures to mandate SI reached the Obama administration in 2013 and they issued this response: "that using the metric system was a choice to be made by individuals". The American people will never accept a metric only system and the world never stop using fossil fuels.(Unfortunately there are about 56 trillion gasoline and diesel motors and jet engines already in existence). Now that is off topic on an off topic!
Congrats to the Milliman lady biologist. OK John, now you have a built-in advisor for starting a catfish breeding business. Start digging a pond.
