Has an armed merchant ever...

[Arclight]

Originally Posted by Quillan

USS Grunion

They found the wreckage recently, and it was supposedly sunk by a hit from a deck gun on a troop transport.

Edit - fixed link. Must have doubled-tapped the CTRL+V keys when pasting the URL into the link. Oops, it's Monday.

Well, most people agree a shell hit may have been a contributing factor, but not decisive. It's still impossible to conclude that it was in fact the Kano Maru that sank Grunion.
http://ussgrunion.com/blog/attack-analysis/
http://www.999info.net/Grunion/HypothesisReport.pdf