If Montana has the Big Sky, the Coral Sea has Big Water. Ever been in water so clear it looks like you need a parachute to keep from falling straight to the bottom? You'll find it off Australia in the Coral Sea. Instead of seeing to the next ridge underwater, you see the next three. When visibility drops to 100 feet, you're having an off day. That superb visibility gets put to good use, with spirelike pinnacles and steep sloping reefs that are home to big schools of jacks and barracuda, lots of sharks, grouper, eels and the whole spectrum of reef fish. The sweeping panoramas make it hard to focus on the smaller picture, but the macroworld has the same high diversity of life. Spoilsport was designed as a live-aboard dive boat, incorporating all the features Mike Ball liked in his previous boats. The twin hulls provide space and stability, allowing for a huge dive deck with excellent walkaround room and large camera tables, a ballroomlike salon and dining area, and a sun deck large enough for volleyball. Cabin space likewise benefits from the catamaran design. Up-to-date engineering systems keep everyone comfortable with air conditioning, fresh water and all the air or nitrox you can breathe through a regulator. Most dives are made from a pair of large inflatables, which nose right up to the dive platforms for easy boarding. A special perk of the Coral Sea trip is a chance to dive the Yongala on the way back to Townsville on Queensland's coast. This historic wreck is far from any population centers on land, so few people get to see it. Sunk by a typhoon in 1911, the Yongala is a flurry of life on a vast sandy bottom. It attracts big animals by the dozens, and you're likely to see anything from turtles and mantas to sharks and enormous stingrays.