ouR escaPOD mods

Standard floor live load for residential buildings is 40 lbs per square foot and the deflection design limit is 1/360 of the length. If you use those numbers and want the reinforcing beam to carry all the load (assume the existing floor does nothing at all) then a 2 x 2 x 0.083 inch square tube will do the job. 

Looks good. I'm not sure whether the side pieces are needed, but it looks good and it will be interesting to compare notes after the braces have been in for a while.

A followup to StephenH,  Installed the bar under the floor of my 179,  although my floor was not having a sagging issue,  it always seemed a bit soft,  after installing the bar it is very solid,  it was a good investment.  Simple design, measure between the frame,  the welder subtracted 1/8 inch to allow the bar to be maneuvered into place.  there was 1/4 in difference between StephenH's bar and the one for my pod and as he said  no two pods are the same! I installed it 15 in from the grey water tank support, just to the right of the left door frame.  Thankyou John Marrucci,  although you went through a fair amount of frustration with FR,  you posting has helped a great deal.