We have a Sunset Creek 2008 289BHS and it was about to fall out a few years ago. A piece of 7/16 " OSB across the frame rails was all that was holding 45 gals up (375 lbs). I upgraded it with steel straps screwed in place and 5/8" plywood. I also included plastic strips between the board and tank to allow air circulation and drilled a few weep holes for condensation drainage. Even now 10 years later, I keep and eye out for sag in the underbelly. Better get a look at it before bad things happen.
"It`s not important that you know all the answers, it`s only important to know where to get all the answers" Arone Kleamyck
"...An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." Col. Jeff Cooper
Sunset Creek 298 BH