Originally Posted by Sailor Steve

So how come in the Torpedo Training Acadamy the stationary merchant suddenly speeds up and moves out of the way when the torpedo is coming? And it wasn't because he saw my periscope, because when I aim one just a few feet forward of his bow he cleverly knows it will miss and he doesn't move.

Yes, I'm pretty sure that merchants can indeed see the tracks from steam torpedoes. It depends on their skill level of course, so they don't always, but they can.