how does marine exhaust work?

Answer 1

same as regular exhaust. usually a vent on top or near the top of the motor. that combustion merely spins the shaft connected to the propellor. exhaust is exited through normal exhaust pipes or even underwater sometimes.

Answer 2

For boats with inboard motors or large outboard motors, the exhaust is usually vented below the waterline (this reduces the sound). Small outboard motors vent the exhaust directly into the air, and larger vessels (such as cargo and Navy ships) vent the exhaust via a stack, well above the main deck.

Answer 3

If you're wondering about the exhaust on a personal watercraft, like a jet-ski or wave-runner. The exhaust pressure spins the prop, which propels the jet-ski.