the whole point of my post about builders van etc etc, wasnt a specific weight of things, bags of cement etc etc, it was to illustrate that alot of people drive around with items unsecured that will kill you
the plumbers who have a gas bottle in the back, if that hits you in the back , your dead
the pallet of paper from the printers, the pallet of bricks, the list goes on and on
once you get above a certain weight , your dead
now we are not talking of not securing your tank, that would be just stupid, BUT that doesnt mean its not doable to secure the tank yourself Or a engineering firm
now i have done mine like this ( its a 400 L LAYFLAT TANK )and as i have said, i have had a guy who makes roll cages for racing cars look at it, he laughed and said how much overkill it was
3 ( or 4 ) heavy duty ( we will say 5 T ) straps , 2 from side to side, the other 1 ( or 2 ) in a X front to back (taking in and through the baffle ), 12.9 rated bolts through the chassis rail ( they will have holes in them, use them holes ) fixing LORRY TIE DOWN PLATES / EYES and as big as possible spreader plates