The puzzle is not at the posted coordinates - caches in Light House Park are currently not permitted.
The posted coordinated are in the water because even virtual stages are not permitted in Lighthouse Park. Go to the parking coordinate for the park and the starting point of the Lighthouse Park Adventure Lab.
You will need to go to this area and complete the Adventure Lab. Contained in the pages of the adventure lab are bread crumbs needed for the puzzle final stage.
The final is: N49 AB.CDE W123 FG.HIJ
You can validate your puzzle solution with certitude..