I don't know if I mentioned that we busted our mast head instruments, including the anchor light, on a bridge gong through the canals, but we did.
In Midland, Hubby went to put on the new anchor light (we'd already bought it, just hadn't gotten around to installing it). He dropped it. He dove for it, and got it, let it dry, and installed it.
So instead, everynight we put a little LED flashlight type light in a ziplock baggie, and ran it up the halyard. Worked like a charm.