> What they're really listening for now are reactor plant noises.
Which is why old timey diesel electric submarines still sometimes have the edge over modern subs. No plant noises at all if they are running silent.
This leads to some hilarity in joint naval exercises every now and then. e.g. when HNLMS Walrus managed to "sink" among others the USS Theodore Roosevelt before getting away, to great consternation of the Americans.
Which is why old timey diesel electric submarines still sometimes have the edge over modern subs. No plant noises at all if they are running silent.
This leads to some hilarity in joint naval exercises every now and then. e.g. when HNLMS Walrus managed to "sink" among others the USS Theodore Roosevelt before getting away, to great consternation of the Americans.