assuming that you have a waist pump, you should be able to put the tank between the current dump valve and the pump. If you have the room it should not be a big deal. Just make sure you buy all of the correct waist equipment and fittings.
thats a big boat with plenty of room.It may have a tank already that has been bypassed.I would search around inside the boat first.Most boats that size have a tank built in from the factory.If it does not ,it will be easy to find the room for it. charlie