So it was a pleasant day out on the water as we bypassed those two spots, pulling into Rosslyn Bay (just South of Yeppoon) late in the afternoon but still in daylight. A cracking sail, too, from memory.
We fronted up to the very nice restaurant for dinner, pretty weary indeed, and then wandered back to bed and ready for a day off.

So with nice weather and the region being open to the public, it was a great opportunity. No phone signal, no townships, no facilities and maybe just an unexploded bomb or two.
So we cruised into the anchorage, cruised around in the dinghy for a bit, and invited the crew of the only other yacht in the anchorage over for sundowners. And slept well!

The screen shot at right, from our up-until-now perfect Navionics plotting software, shows our anchor marks, planned course, and the red spot's our impact point.
Yes, we should've kept a better watch at the bow. And yes, we should've picked our way out of the bay at a slower speed.
And no, we shouldn't have trusted the chart so faithfully. Anyway, "just a scratch" as they say in the classics.
And there endeth the lesson.