Over kill on the boat dock lighting

I have a problem.  The persons across the river has put in a 24/7 bright light on their dock and it shines right into my bedroom window from across the river.  It is so bright   you would think that it is a search light and to me even odder is they have it on all day and night.  Yes I close the curtains half way and that helps but not when you want to sit out on the deck late at night and relax.  Any suggestions, comments are welcome...thanks