Shipping lanes off sunshine coast?

I'm sitting on King's Beach and watching huge ships heading north, turning around a bit further on and then heading south, seemingly as close in as they were heading north. Why do they do that? I assume it has to do withing shipping lanes but why the u-turn?
They would most likely be in the North West Channel when heading towards you and then turning to head out. The shipping channel is needed to avoid the sandbanks littered through Moreton Bay.
I'm sitting on King's Beach and watching huge ships.....

Was a lovely day for it Wylie. ;)

Speaking of ships..

We often play "spot the ship" as they sit off Mooloolaba waiting for their Pilot to guide them through to Brisbane. I heard that this was a necessity. I am surprised that it isn't a given up at the Barrier Reef, with the shannigans going on up there in the shipping lanes. :eek:

I am amazed at how huge they look even though they look fairly close to shore. They must be awesome up close.

Awesome is not the word I would use - they are terrifying !:eek:
Very scary to be crossing the path of one in a private boat.