I have a 2007 250 SLX with what I call the radar arch. There is a company that makes a telescoping cover that attaches underneath the radar arch and it will extend a good 6' or so. I've seen it with power and with a hand crank. Both work well. This is the link to a YouTube video of one in action. The owner is of the boat is in the comments. Hopefully he can help. https://www.youtube.com/watch?v=CSw4cFcYrKM