If you wish to operate your boat commercially as a full time business, or just occasionally charter it out to help cover the running cost, you must comply with the MCA Codes of Practice. There are many different Codes of Practice to cover sailing yachts, sport fishing boats, RIBs used for thrill rides, boats taking workers out to wind farms and oil rigs, etc.
In most cases this is not a particularly onerous process. If your boat was built after 1998 and CE marked, it will be compliant with the EU Recreational Craft Directive. This lays down a specification for the design and construction of the vessel, and the MCA Code makes use of many of the same standards. The additional requirements to meet the code will be mostly the provision of sensible additional safety equipment, and the marking and labelling of locations.
We can assist you with this, Medusa Marine is a nominated surveyor for MCA Code of Practice for Small Commercial Vessels, working under the auspices of the YDSA as the Certifying Authority. For full details click here