Frank&Mike...We have one of those and we really like it. I just went out and looked to see how it is mounted... First it is a Valterra product. I went on line to their website...you can download a catalog here
and the "EZ Hose Carriers" are shown on page 16 of the catalog. (Those in the catalog are white, but ours is black which I like better because it "disappears" visually.) They also show the two brackets that are used to mount them...one at each end. They come in various lengths...I didn't measure ours, but it is probably the 46" size and it will hold two 10' hoses. There are twist-on closures at both ends that are vented so the hose can dry out. According to the catalog the tube is 4.25" in diameter. Ours is mounted with access at the street side. One bracket is attached with metal screws at the inner edge of the curved edge of the bellypan, and the other end is attached by metal screws, one of which is in line with a number of rivets in the belly pan...I presume there's a beam under there that the belly pan is attached to...the other side opposite where it is attached in line with the rivets appears to have a plate inserted between the bracket and the belly pan ... no doubt to give it more stability where it is screwed to the bellypan. Ours is installed at a slight angle in order to avoid the exposed propane lines. We did not add ours...it was on the Bambi when we got it, but I don't see that it would be a difficult thing to do. It probably comes with instructions. By the way, a friend of ours has two or three of these and uses one or two of them for rugs, etc...they'd be good for anything that is long and narrow like fishing poles, etc... Hope this helps!