In EU countries, Australian do not need a visa, but are restricted to 90 days travel every 180 days. This is often called the Schengen visa. In non EU countries, you might need a visa. Turkey
requires you to have a visa before you arrive in the country. You can get it over the internet
. Some countries might issue a visa on arrival. So, if you plan to visit non-EU countries, do some research
. An Australian flagged boat might require a temporary import permit
which is good for 18 months and is renewable. I think most of "us" have not been asked to apply for this and merrily go about their Med Cruising to 3 months. The only time we have had this time checked is when we leave the EU, but this is not a certainty. Some. Non-EUs stay longer but run the risk of getting caught and then having their right to easy entry greatly restricted or even refused in future.