Your dealer will explain the security system, this will not be posted on line. Or a call to BCB with your hull ID number and they will explain it to you. The 3 discharges on some and i may be wrong here, but one would be for the bilge, one would be for the automatic bilge, and the third would be for the pumpout. You may or may not have the pumpout, though if it has the security package then it should come with the pumpout as this was a premium model P4 (new P4 are not premium models and have options for this, so if boat is new id check to see what options are listed on the boat). Now if you have only two discharges in the back the bilge and the auto bilge may be tied together utilizing the same hoses/discharge for the pump out of the bilge water, and the 2nd would be for the pumpout from the livewell. Someone from BCB will be along shortly to verify…