Strapping things in van ?

How would I strap these DI vessels to side of van? Also, barrels and other stuff?

 

Might be best to build a ply box, screwed to the floor (or non slip feet on the box) that holds them nicely, put empty ones back to keep them stable till replacement ones bought.

 

cargo net ? The other option might be to run two additional straps through the handles and fasten to floor loops

 

By handles u mean holes in the metal wall and ceiling chassis?

 

handles in the water carriers

 

In addition to securing them a non slip Matt to the floor helps stop any sliding.
(As used under rugs and carpets)

 

Should I take ply floor up? Worried about water getting under there and not coming out. Could paint it as well

 

Are you worried about crash protection, or just sliding about? For the former, you really want to make sure that whatever you use can withstand about 20 x the weight of whatever it is you're trying to secure, against a forward movement.