The USCG charter laws in Charleston Limits the number of passengers to be carried on a vessel for hire to 6. This is why you see so many charter boats with the capacity to carry 6 people. To carry more than 6 passengers a vessel must be inspected by the USCG.
Inspected vessels are built to a higher standard than a regular vessel. They also get inspected every year for safety. Finally they have had a stability test done to make sure the number of passengers allowed on board is safe.
Why does this all matter for you?
Inspected vessels are not as common as every other boat. The cost to build, own, maintain, and operate is higher. That is where it affects you. Costs for groups over 6 passengers are more expensive than for groups of 6 or less.
Warning! The USCG is cracking down. People offering to take large groups out without an inspected vessel have been taken to jail. Don't let your group miss out on a fun day on the water by booking an illegal boat charters in Charleston.
Below is a link to an article of exactly why you need to have a licenced competent Captain and Inspected vessel for larger groups.