Never heard of it?? I've always thought of it as a famous story; the only time an actual warship was tricked and sunk by a glorified merchant.
On the other hand, it may be because of my fascination with the previous war's HMAS
Sydney, which tracked and sank the infamous German light cruiser SMS
Emden.
http://www.worldwar1.co.uk/emden.html
The adventures of SMS
Emden and the stolen schooner
Ayesha would make an amazing movie.