Two hundred kilometres off the coast of northwestern Australia,
a rigging crew is about to start the day.
We are up to mooring leg number eight.
Don't become complacent.
We're halfway through it, we'll get the next eight done safely.
But this is no ordinary day at the office,
because they are about to moor the largest floating facility ever built.
Look, it is absolutely fantastic.
I've had about four or five years, I've been thinking about the mooring system,
so to now actually be here, pulling these things in, fantastic!
I am absolutely stoked, honestly.
At 660,000 tonnes when fully loaded,
Prelude weighs six times more
than the largest aircraft carriers in the world,
and it will operate in an area known for extreme weather conditions.
The need for this mooring system to work is critical.
We could hit the cyclones and this mooring system will hold us in place.
To do that, the project team has created
one of the strongest mooring systems ever built.
Deep inside Prelude is the turret
that allows the facility to rotate, or weathervane.
Beneath Prelude, one of the largest chains in the world,
nearly 25,000 links
attached to mooring piles drilled deep into the ocean floor.
Now the team is preparing to connect chain number eight,
making Prelude officially storm-safe.
What's incredible about this is they'll be pulling in one or two links
that they've already predetermined during the pre-lay,
which is quite an incredible feat of engineering and installation.
The operation to moor Prelude begins
with the rigging team making the steep descent into the bowels of the turret.
Outside, three tugs are holding Prelude in position.
The crew on the Deep Orient has retrieved the mooring line.
On Prelude, a giant winch is standing by to haul in the chain,
and the engineers are ready to monitor each and every move.
Everything is in place.
All positioned, ready to go, so it's now up to the team onboard to finish the job.
- Yellow winch pay in, easy. - Yes, pay in five metres.
This is the main event,
we are pulling in the chains one by one and connecting them off.
This is the culmination of years of planning
to bring this to a head - awesome, absolutely awesome.
Remezel winch, copy.
What loads have we got on the winch at the moment?
Slowly but surely, the winch hauls in the chain.
Winch, good to go another four metres. Pay in four metres.
Yeah mate, coming up.
And it begins to emerge...
You can probably see the yellow socket,
just over the side here.
That bang you just heard, are as the chain comes through the chain connector,
the engineers are looking for a particular link
and that's when they know they've pulled the chain into the right length,
and that is what then holds us in place to the seabed.
A final turn of the winch...
...and the last link locks into place.
Dive control, turret.
Copy.
Confirm, please, that the golden links are sitting nicely.
- Yep, that's correct. - Yeah, understood.
We're clear to release the load.
All stop on the main winch.
That's all stopped, mate, all stopped.
And with the eighth mooring line connected,
Prelude is storm-safe.
- Landed. - Making history.
So this is one of the 16 mooring lines
that will secure the Prelude facility to the seabed
for the next 25 years.
This is number eight, so we're not going anywhere.
This is fantastic!
Great job, thank you very much.