Bottom Discrimination is only enabled when certain transducers are connected.
The SS270W is not one of them.
The following transducers are needed to enable Bottom Discrimination:
FCV627, FCV587, BBDS1-
520-5PSD Plastic Thru-Hull Transducer, 600W (10-Pin)
520-5MSD Bronze Thru-Hull Transducer, 600W (10-Pin)
525-5PWD Plastic Transom Mount Transducer, 600W (10-Pin)
525STID-MSD Bronze Thru-Hull Multisensor with High-Speed Fairing Block, 600W
525STID-PWD Plastic Transom Mount Multisensor, 600W (10 Pin)
FCV587, BBDS1 Only- MB1100 Required) -
CA50/200-12M Bronze Thru-Hull Transducer, 1kW (No Plug)
CA50/200-1T Rubber Coated Transducer, 1kW (No Plug)