"Do I list my boat in the Florida State Tangible return?"
Boats are specifically excluded from ad valorem taxation by Section 1(b), Article VII of the State Constitution.
However, you might want to contact your county property appraiser (link below) for further information in the event you need to file a return for any other property you may use in connection with your business.
Note that filing a DR-405 preserves the exemption on the first $25,000 of assessed value.
See http://floridarevenue.com/dor/property/appraisers.html