Did not realise until I discovered this poster what the Lusitania was, but my guess was a huge boat the Germans sunk in the WW1. Britain using every tactic in the book to boost numbers in the forces at the time. Found a really interesting book about it
Was this due to lack of food and rations? Wanting the resources to go to the troops? Maybe all food was short in WW1 and people being prudent in every aspect of their lives helped the troops keep stocked up on vitals.