problem i hve now is how the hell am i gonna fix a tank in the back?
i was gonna weld a cage to the racking that would of secured the tank nicely but now i'm gonna have to look at other avernews. i used to have a berlingo it had fixing points in the back this kangoo dont seem to have although there are threads to fit bolts in that the ply board was fixed to. do you think i can get eyelets to bolt in and if so are they gonna be strong enough?
I'm glad you're going for the 400 litre tank,... realistically you couldn't go much bigger without worrying about payload,.. but 400 litres will be just enough to keep you going all day if you are careful.
As for fixing it to the van,.. think about it seriously. I know all the rubbish that Ionics have propagated about crash testing has got some people a bit worked up,.. but the general principle is right. You'll have 400KG of water right behind you. In a crash that might otherwise leave you uninjured, the tank has the potential to kill you.
Rachet straps can be strong enough,.. the problem is that the eyelet fixing points in the van aren't!
I would recommend getting a local welder/fabricator to weld up a frame,... this is a pic of one of the bast ones on the market:
Get him to bolt it through the chassis of the van with some seriously heavy duty bolts (16mm High tensile if possible) and use spreader plates where the bolt contacts the chassis. 8 or 10 bolts would be required depending on the position of the tank.
On some vans the fuel tank needs to be dropped before the chassis is properly accessible,.. but so long as you don't have to do this it shouldn't cost a whole lot. My one was built and installed for €120