As a gladstone local I can offer some help.
The barge trip is expensive to run the tinnie trailer over. The 6m glass boat will get you to the island with all your gear very easily.
Solar panels and a fridge is a must for keeping 5days worth of fish.
No petrol generators or fires allowed. Gas cooking only.
The mutton birds are not too bad. Just have a good solid food container and keep everything packed up when your not around.
The access in and out is best done on smaller tides. So keep the dates scheduled around the neap tides. Leaving the boat in the water is a preferred option and just walk back to shore. Snorkelling gear is helpful to wrap the anchor chain around a bombie for nighttime anchoring.
It's worth a call to the barge company for any future school camps being booked on the island. Obviously avoid them.
But generally you should have the island deserted.
The big boat will need 150km of fuel just to get out and back. So work out your consumption loaded up with gear and take extra for the day trips to close reefs/shoals.
Another option for the boat to be beached is a well positioned piece of carpet under the keel on the sand. At half tide etc.
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