Somewhat OT, but we had a delayed QF flight last Friday from PER-SYD. We were booked on QF644 which was an A330 with an 1100 departure. Quite close to boarding time, the board showed a gate change, where there was another A330 being readied for flight. It turned out that the original aircraft had been on tha tarmac overnight, and when opened up, they found the whole floor of the aircraft covered in water. They tried for 3 hours to clean up the mess using wet and dry vacuum cleaners, but could not get it to a fit state for flight. They were also concerned at what other damage the water may have done that couldn’t be seen. Where on earth would that much water come from? Once onboard the alternate aircraft, we were advised that it had an engineering issue on the starboard side which took almost an hour to be resolved. Whilst we were pushing back, the Captain told us of the issues with the other aircraft, which had by then been grounded, and was being prepared for a tow to a hangar. So we departed 2 hours late, made up about half an hour during the flight, but once close to SYD, were put in a circuit and lost what we gained. Further delays occurred at the gate, and then 2 aircraft loads of baggage were allocated to the one carousel, and the bags all came down intermittenly. After arriving at 1900, we eventually left the airport at 2100. So a short 3.5 hour flight turned into along day in the saddle.