Good point and you can never be reminded of this too often. Usually when the engine won't start it happens at the worst time, like at two in the morning, a bad squall, and having to get out of someplace fast. In these circumstances it's easy to forget and keep cranking away at the engine. If the engine won't start after two or three cranks, go down below and shut off the cooling water">engine cooling water intake!
When it starts you can open it again. If you don't do this you run the risk of "hydrolocking" your engine and if it starts with water
in the cylinders it'll bend your piston rods and shear your crankshaft and god knows what else. Don't ask me how I know.