This made me think of other fluke hazards that people encounter on the water such as rogue waves, water spouts, whales or surfacing submarines. But the real, biggest threats to boaters I've witness are rocks, the submerged kind. Or, as one dockmaster buddy refers to them, "elephants." My brother encountered one such elephant driving my dad's boat a few years ago. The water levels on the river were extremely low and a submerged rock known only to old-timers no longer had clearance. My brother, cruising at a 30 mph clip, watched in horror as the lower unit of a 150-hp outboard sheered off in a split second. Thankfully the hull was not breached and the engine was covered under insurance.