He posted this in the Magellan Meridian Yahoo! Group...
I know my Magellan Meridian Platinum (same as yours) is waterproof since I have taken it into all sort of water extremes and I also know that taking it on a water slide is the funniest thing I have ever heard someone do with a GPS.Call me crazy but I took mine on a waterslide to see how fast I went at a
mini theme park on holidays.
I dare say the 25-30kmh imersion at the end created higher pressures than a
normal dunking.
Several runs averaging 25.8 kmh and no water ingress.
I'm happy.
Dave