Bottom line is many places have significant restrictions on non-nationals working/ taking jobs from the locals... Permit
Process is generally Never one you can accomplish in a day or two and some prohibit application if you are actually in the country... you have to apply prior to arrival.
In the real world... cruisers do work for other cruisers under the table so to speak. It would be more difficult to do it outside the cruising community and you are always subject to problems if someone feels you are taking their job away from them. It is always harder to let the word get out about you desire to work when at the same time you want to limit the word getting out too far.