Nuclear subs only need to dock somewhere about every six months from what I have read as they are technically capable of remaining at sea for long periods. I am sure the crew like to dock more often than that though.
As far as the subs themselves go with the first one due for delivery in about twenty years time they should not upset China too much. The world will most likely be a different place in another twenty years at current rates of change. The biggest news today should be how much Australia is paying the Froggies to break the big contract that this government signed.
