mts...two issues occur to me...but I do think you have the size right and the need for equalized guest accomodations.
1. You will need a captains license and appropriate commercial insurance. In Europe you may face a whole bunch more requirements.
2. I don't think you will be allowed to set up a charter business easily in Europe unless you are a Euro citizen. You will have to leave the EU personally due to the Schengen treaty after 90 days and stay OUT for 90 days... and the boat will need to go to a non EU country every 18 months.
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