There are a number of factors that determine the maximum capacity. 1) The Captain/Operator's experience 2) the passengers/crew's experience 3) the particulars of the trip being undertaken 4) the current, anticipated and possible weather conditions 5) and lastly the size of the boat. The USCG has placed the responsibility to determine the maximum capacity in boats over 20 ft. on the shoulders of the Captain/Operator. The Captain is responsible and will be held accountable for his decision regarding maximum capacity. Regarding #1, experience, the captain must know the performance limits of the boat under different loads, should be able to foresee adverse situations and be resourceful enough to handle those while insuring the safety of the boat and occupants. On #2 the Captain must assess the experience and capabilities of the crew/passengers, obviously the more experienced the crew is and the passengers the larger the capacity, any medical issues or handicap should be noted. #3 What is the duration of the trip, how far away from land, and the types of water conditions that predominate. #4 What is the weather like, what is the forecast and what is the likelihood for it to turn foul during the duration. and #5 the size of the boat, the Captain and crew need room to move about the cockpit to safely operate the boat, If passengers need to be inside the cabin for an extended period of time it will not be pleasant for them and might induce nausea and dizziness. Also people may not sit on deck for an offshore trek. If it were me with one experienced hand I would take up to 10 for a short inland waters ride, but for a trip to Catalina I would limit the trip to 4 in a boat that size. I do value comfort and more than 4 would push the limits of me being able to move around in a comfortable manner.
