If this is the boat from where you intend to conduct your business (as per your other thread) then the licencing may not be as simple as the above answers suggest.
On C&RT waters, for example, you will need commercial insurance, a commercial Safety certificate (as you have paying customers coming aboard) and a commercial boat licence.
I do not know what requirements for 'commercial operations' licencing the other navigation authorities will have.
If you are intending to operate the business from within a marina, you will need to check if they allow business to be run from the boat - many do not ! (car parking issues, 'strangers' wandering around the marina etc etc)