That is the pipe-hose adapter I use.
There is nothing wrong with PVC/ABS pipe on a boat, and it is a much better choice than hose for sanitation purposes. Those who think that boat builders do not use it, must think that all of the larger boats are plumbed with miles of Trident hose snaking through them, and over several levels?
The problem on smaller boats is they don't have many straight runs, or ability to get PVC pipe to run through them without cutting a lot of access. But if you can use it, even in sections connected with hose, it is far superior, much, much cheaper, resists calcification, and available in even the remotest places for replacement/repair.
Of course a PVC pipe installation needs to be supported. It needs this in houses too. Even hose needs to be supported, because if it is allowed to dip, it will pool sewage in it. As for cracking, etc, just go to any of the Caribbean islands and look at the miles of PVC pipe running along the ground in full tropic sunshine without issue. But flexing isn't the damaging thing people make it out to be. Go ahead and grab a section of PVC pipe and start flexing it 1/4" for a year and see what happens. PVC runs on boats are not flexing themselves into circles and loops - they are just vibrating a bit at the most. Since all fixed ends necessarily have a section of hose connecting them to pipe, any movement is not really translated into the pipe anyway. It isn't even translated into the pipe-hose fitting.
I've plumbed two of our boats with PVC for sanitation from toilet to tank and have never had any issue with it. These were catamarans with long runs that went through several bulkheads and required several bends. The PVC has outlasted all hose and has never permeated or calcified.
Mark
