Fluid flow through any venturi has the following effects:- Velocity increases Pressure decreases Temperature decreases. These changes can be dramatic and are real. Piston engined aircraft operated by pilots who wish to live a normal span of years select `Carb Heat' to prevent/ reduce the probability (NOT `possibility`) of carb icing. As for the moist air not being present in a boats engine room- how far away is the water? Why do the majority, if not all, cars have air intakes arranged to draw heated air? Why do clouds form? Why do aircraft often have de-icing or anti-icing equipment? How far away are aircraft from water? A darn sight further than a boats engine, I bet. Rick may have been outnumbered, but `twas only by the unaware and ignorant. The first are excusable, the second are not.
