May wish to check with a LDS or two in the area, but here are some suggestions. You stated that you didn't want to drive too far, but that's a relative term. I drive 45 miles to get to the nearest town from my house, and I don't consider that far at all, meanwhile I have family that live in Rhode Island, and they can travel the distance of the State in that time. Anyway, check these shore dives out. There might be something here to interest you.
Stuart Area:
Old Schooner Wreck ... Hutchinson Island
Bathtub Reef ... Hutchinson Island
North Jetty Reef @ St. Lucie Inlet
Jupiter Area:
Blowing Rocks ... 2 miles north of Jupiter Inlet on A1A
Coral Cove Park ... 1 mile north of Jupiter Inlet on A1A
South Jupiter Island Bridge
Carlin Park ... South of the Jupiter Hilton
Delray Beach:
Freighter ... 150 yards off the South end of Delray Public Beach