Updated: As mentioned in the comments below, another issue with ICEs is water—which is incompressible—getting into the engine via the air intake.
Model S firmware Easter egg: turn a picture of your car into a submersible Lotus Esprit.
Obviously we don’t know exactly how well-sealed other parts of the Model S are, but it’s safe to assume that the battery pack—which contains lithium, which bursts into flame on contact with air or water—is fairly impenetrable. The fact that the Model S has a “bioweapon defence mode” also suggests that the cockpit at least is very well-sealed.
Tesla may have known about the Model S’s boating capabilities for a couple of years. Back in early 2015, a firmware Easter egg was discovered in the suspension settings screen that allowed you to turn the picture of a Model S into James Bond’s submersible Lotus Esprit.
Before you head down to your nearest slipway for a little dip, though, be aware that Tesla “definitely doesn’t recommend” using your Model S as a boat. I wonder if it negates your warranty…
We *def* don’t recommended this, but Model S floats well enough to turn it into a boat for short periods of time. Thrust via wheel rotation.
— Elon Musk (@elonmusk) June 19, 2016