The lighthouse took more than 50 years in the mid-1800’s to go from authorized to funded to constructed and even then, the boat carrying the metal structure elements sank while enroute to the island. The tide table for Sanibel Island is calculated at the lighthouse. I don’t understand tides much, because the low tide at the western end of Sanibel Island is about 30 minutes later than the low tide at the lighthouse, but the high tides are only a couple of minutes apart.