The advantages a ssn ( nuclear ) sub has over a ssk , lends well to defending Australia, because of the vast distances .
ssk subs are slow and need to snort ( come up for air , for the engines , batteries and circulation) every 12 hours at low speeds .
At fast speed and being quiet ( using batteries) not much more than a few hours, and then would need to snort for 3-5 hours to recharge.
ssn subs can travel 1000s of k’s independent of air .
