Southco MF-97-917-41 Modella Key. The 900 series keys are used on many Southco and Modella locks. They are typically found on Sea-Ray, Bay liner, Tiara, Well craft, Chaparral, and Maxim boats, and many others. The three digit code can be found on the head of your current key or on the interior handle of your latch or lock. You'll be receiving an OEM cut key that will fit perfectly.