Our 2011 3170DS rear pass through storage bay was sagging abit in the middle... We use the rear bay for just about everything... Easy up, folding tables, zero gravity chairs, homemade wood leveling ramps, list goes on and on.
About 3 years ago I noticed the sagging in the middle between driver side and passanger side was causing the edges to pull away some. I added two angle iron (boxed the end where it goes over frame) that goes all the way across. Tack welded to the frame. Everything sucked back up and bay has not de-formed again.
2011 Sunseeker 3170DS - 30,000 miles explored