Storage of boats outside; exceptions. No person shall be permitted to store any boat or boats outside in the General Commercial Zone. The foregoing notwithstanding, on any parcel of real property located within a General Commercial Zone and which is currently occupied for an exclusively residential use, one boat may be stored in the back yard thereof, provided that the same does not exceed 24 feet in length, is owned by, and if required, registered to, a resident of said parcel and the same is reasonably screened from view from outside the borders of said parcel and/or appropriately covered.