As a new Ocean owner I have performed my own bellows tests using a hose pipe and spray gun attached to a step ladder in front of the van. Spraying a fine mist at the bellows for 30 mins followed by letting it dry for an hour produced some interesting results after I had repeated it 3 times. The aim was to try and simulate typical UK rain showers. These are my observations:
1 - The fabric leaks at the base of the vertical seams and pano zip where they join rubber seal on the roof. There are also pinholes in the fabric at these points where the stitching has been stretched. These holes looked to contribute to the water ingress.
2 - There were signs of water ingress along the whole length of the fabric where it joins the rubber seal but much worse in the corners where it’s under higher tension.
3 - Drips form through both vertical seams and both vertical pano zips. There were no signs of leaks along the top edge of the pano zips.
4 - The bottom of the window was the first place to leak at the left hand corner (looking from inside). It dripped about every 3 seconds. As the lower window seam became saturated it dripped less in the corner but profusely along the length of the seam. Even after the hose was switched off, drips continued to form for another 10 minutes, showing just how saturated the fabric had become.
5 - The horizontal seam above the window had very similar symptoms to the lower one. It started dripping on the right hand end where the fabric is doubled over and then along the whole seam.
6 - It was difficult to detect any water ingress from the window zip itself as water from the horizontal seam above ran over it.
7 - Once saturated, the bellows fabric took hours to dry. I even used the diesel heater on max but ended up lowering the roof and keeping the hatch open overnight.
In summary, I think several factors contribute to water ingress:
- Fabric tension, especially at the bottom of the bellows and particularly in the corners.
- Fabric saturation. Once saturated water will ingress at a shocking rate and will continue to do so for a while after it’s stopped raining.
- Stitching. Definitely appears to be a factor. The horizontal seam above the window shows stitching ingress, but also signs of some fabric saturation.
- Needle size. This was mentioned by
@Viktorgeorge earlier in the discussion, but looking at the small holes along then bottom edge of the bellows, this could be a factor during manufacture.
I may do some further tests next week if we have a nice dry day!