A bit off-topic, but where did you prefer north of the Blue Heron Bridge? Is there a dinghy dock nearby? Or are you referring to a marina?
I've never gone north of the BH Bridge, but it seems you have the clearance at low tide, so it might be worth investigating. The City of WPB has the City Docks off the downtown area closed for Sunfest, and I'm trying to finish up the new electronics on my boat, which is made a bit tougher without someplace to land the dinghy for parts!