AIRLIE BEACH: EXPERIENCE THE ULTIMATE REEF TRIP! Cruise through the stunning Whitsunday Islands and on to the outer Great Barrier Reef on board 'Seaflight', the Whitsundays' premier day cruise vessel. Experience Queensland's most innovative and spacious reef pontoon located at Knuckle Reef. Knuckle Reef Pontoon features Queensland's largest and most spectacular underwater viewing chamber and is the only reef pontoon in Australia with a giant waterslide. Explore pristine Knuckle Reef Lagoon, acclaimed as the region's most spectacular Great Barrier Reef site.