Australia's coastal surveillance

For those who think Tony Abbott's going to stop the boats, a primer by a former Admiral on the challenge of coastal surveillance.

Furthermore:

And where would you take the Sri Lankan boats back to? Would Indonesia accept them?

Armidale class patrol boats were designed to conduct boarding operations in support of immigration and fishery laws, but it's over 5000km to Sri Lanka from Australia's north west coast; the Armidale class does not have enough fuel to escort the boats back to Sri Lanka, and refueling at sea is not a viable option.

Larger ships such as the ANZAC frigates could possibly reach Sri Lanka, but depending where it started its journey, an ANZAC frigate may require a refueling ship or port visit to complete the operation. Assuming you use a refueling ship, the cost-benefit analysis of such an operation for a Sri Lankan boat carrying 200 people would be prohibitive.