I agree with AW about it not taking a river crossing.
It's the tranny that I always find full of water. People talk about this oil or that oil making your tranny last longer. I think the thing that is going to make them last longer is keeping water out of the oil. A remote vent would have to help during water crossings and whatnot but I know from experience that 95% of the water that gets in there on a street bike is getting in there via the speedo cable. Shrinking electrical wire shrink insulation over the cable and boot 100% solves the problem. Same thing with carb and choke junction boxes that are constantly getting filled with grit without the same trick. It keeps them absolutely perfectly clean for a LONG time. Till you need new cables in my experience.