An experiment - hope it works

You were all helpful when I wanted to know about 3 way fridges, so hopefully you can help me out with this query. It's a bit more complicated than the last one :)

An idea has formed to attach storm water piping around the top of our cruiser canopy frame so that we can have shower water etc at will while away on the beach.

So far we have cut the piping down, joined them and put a 2 way tap on one side. Problem is, is that at the moment we've attached the piping(along the top inside of the canopy frame) roughly with rope to hold it up til we find something more suitable.

We have tried wire (obviously not the piddly stuff) but looked a bit risky (all up, the piping would hold roughly 40 L to 60 L of water), bought some extra thick zip ties but they fell a little too short.......thought about joining them together but a bit wary about that as well. I did think of getting clamps but am thinking that after a while they might rub through the pipe and put holes in it.

So right now, we're at a dead end. It was an experiment to begin with but now we've gone this far and the clocks ticking down the time to when we leave, I'm starting to panic a tad!

Anyone have any suggestions?