Chartering is the word that sticks out there like a sore thumb. You will need to choose and equip the boat specifically for this, and ensure that you can insure it appropriately. That won't be easy, especially on an older boat. Getting the paperwork and licences required especially overseas will be the next level of complexity. Unless you know exactly what you're doing you may have to delete that part of the plan. If you plan on doing it under the radar
then choose a boat that's cheap
enough that you don't mind it being confiscated.