Keep a roll of the ships that used to be Greek and are now flying the flag of convenience. Want to go to the Black Sea or Istanbul? You better hope your tax is all paid up, because otherwise the Greek government will seize that shiny asset you're brining into its jurisdiction as down payment. And the cartoon joke country whose flag you're flying does not have enough gunboats to escort your ship.

Or, as you note, you could just start confiscating domestically held assets until they behave.

Of course, shipping really needs to be taxed at the European level, with any shipping company that wishes to dock in any European port having to pay up the difference between European corporate tax and what they are paying in their flag of convenience country (and having to pay their crews European wages).

You can push around a small country like Greece. You can't not do business with the EU.

- Jake

Friends come and go. Enemies accumulate.