I am also a fan of solid PVC pipe for sanitation purposes and its apparent ability to significantly decrease or eliminate "head" odors. However, my installation
of rigid PVC pipe uses supports before and after every joint and elbow
and every 12 inches (30cm) for long runs. Each support has a rubber wrapping around the pipe underneath the strap or support clamp. This allows a minimum amount of movement to mitigate shock loads and keeps the pipe from "whipping" or flexing due to boat motion.
- - Also it is important to know and follow the real gluing techniques and not the quickly procedures to ensure a full strength bond at each fitting. Just like glass plates and wine glasses, it they are properly stored and handled they will not break.
- - My philosophy on boat systems involves engineering and installing each system so that you could mentally grab the keel
of the boat, turn it upside down and shake it - and nothing would - theoretically - come loose or break. As a cruiser you will be caught out there sometime or other in some really nasty seas and winds. You will really get an up close and personal experience of what it is like to be a cork in a washing
machine. Having the insides of the boat come apart is not conducive to personal longevity.