The only good place to anchor in Ft. Lauderdale is in Lake Sylvia. The water police occasionally hassle you there but they haven't been there the past few years. It's fine for a weekend. Lots of locals anchor there on weekends. If you want to go ashore dink down 17th St. causeway to the Southport Raw Bar.
Expect local ski-boats that use also, they love doing donuts around the small
lake, what pain in a$$.