You should see the navigation in the DCR boat at the Q its pretty impressive to run full tilt in the dark.
There are two huge orange blinking "buoys" at Wachusett. They monitor water quality/ relevant meteorological conditions - for the water supply side of things. Nothing to do with fishing or navigation. I think they are big floating weather stations basically. Also, for bird control at Wachusett they shoot off these flash/bang sort of things from shore - usually around the rook area. Scares me, seems to do the same for the birds.