Nothing is truly waterproof...
In the final battle, vs the titan dweevil, keep an eye on his body movements. Watching these can help you predict it's next attack. Here is the range of it's attacks:
Comedy bomb: entire circular arena
Monster pump: Entire sublevel
Shock absorber: varies(never further than arena)
Flare cannon 50-80mm in your direction(WARNING! This can hit you even if you are in the space surrounding the arena. This goes for you pikmin, too.)
Telling by this data, you get the feeling you should attack the monster pump ASAP. If it turns blue and grabs the pump off it's head, run to the other pilot NOW. While the dweevil fires giant globs of water, keep blowing your whistle throughout the attack until it stops. Since you don't have a waterproof suit, you will take damage if a blast hits you, keeping you from calling pikmin that are drowning, so keep your pilots out of the way!
Added by: mastersurgeon Jun 18th 2007, ID#7692