I'm not exactly sure if this is what you're talking about, but I recently went
out with a friend who had a trolling plate installed behind his propeller. We
went out rapidly to where he wanted to troll, and then he discovered to his
dismay that he'd forgotten to unlatch it before we left the dock. A 150 hp
outboard motor running wide open will bend the plate straight out behind the
boat and leave a permanent bend in it!