This tower is very close to the library at Semaphore, it's on a hill right across the road from a park and the beach. I figured out fairly quickly (and some time ago) that it wasn't a lighthouse. But until today I didn't know what it is. Turns out it's a time ball tower (geocaching can be educational, who knew?) that mariners could observe to get an accurate time at 1pm each day.
Also, I've met all three resolution goals for the month already. Looks like I'm set to exceed some, if not all, of them.