The caster at Port Kembla usually produces 230mm thick slabs...

The caster at Port Kembla usually produces 230mm thick slabs however can be converted for a small run to make 300mm thick slabs which is used for producing the thicker end of the plate product range (>100mm thick plate). At one stage BSL were importing these 300mm slabs as it was too expensive to convert the caster over to produce a small run of the 300mm product. I don't know if that is still the case.

I'm not sure that the Port Kembla plate mill will have the capability to produce all the sizes of plates required for these subs. I believe the thicker inner hull is rolled from plate that needs to have a length equal to the diameter of the hull. The maximum mass that can be produced off the PK plate mill is around 10tonnes.