Wait a minute, off topic, how the crap could Luffy be carrying the mast from the ship when Jimbei shot him in a water burst in front of the 3 Admirals at Marineford. DF users are supposed to lose strength/power/ability in water correct??? Sorry it just jumped in my head outta nowhere.
Gradually (though very fast), not instantaneously. Some are even immune to it. Aokiji for eg(Dude is Ice, he floats when he falls on water)