Crestliner Boat, SureMount rail Mounting of Baseplate .
Gunnel widths are typically 4 inches for Crestliner boats. If yours is more, select a proper baseplate from the dropdown list.
Note that Crestliner uses mutiple types of mountings depending on the model of your boat. So you may need to use a 90 degree bracket or one of the other brackeets with an 8.25 inch baseplate assembly