Personally, I think they should put a daymark at/near the northernmost and southernmost rock of the Witches. Use a telephone pole (to handle the winter ice) and put solar-powered lights on top. I feel daymarks are good navigational aids because they are easy to see and they do not drift out of position.
Here's what they look like.
www.bizer.com/lwother/daymark5.jpg
www.bizer.com/lwother/daymark6.jpg
www.bizer.com/lwother/daymark1.jpg
www.bizer.com/lwother/daymark3.jpg
www.bizer.com/lwother/daymark4.jpg
If anyone put something this conspicuous on their shorefront property, Bizer would probably put it on the map as a navigational aid.