We’re amazed that more boats are not plumbed with ordinary PVC pipe, but then again we never thought of using it either until we bought Morgan’s Cloud 16 years ago and found that her builder had used PVC pipe for almost all of her plumbing.
Since then we have added several plumbing systems in PVC and modified existing ones.
Among the benefits are:
- Economy. PVC pipe is dirt cheap. The total at the cash register after you buy several lengths of pipe, together with the fittings and glue to go with it, comes as a surprise—a pleasant one; particularly if your last stop was a yacht supply shop (chandlery).
- Availability. Even a small corner hardware store has enough PVC plumbing fittings in stock for most jobs and the bounty in the bins of a large building supply store will let you build almost anything.
- Flexibility. No, it does not bend, or at least not much, but the amazing variety of PVC pipe fittings allows you to solve some very vexing problems surprisingly easily. Want to connect a 2” line to a 1/2” line and then T off a 1” line? A quick trip to a hardware store and a bit of ingenuity and you are done.
- Fast Assembly. With a little practice and a pipe cutter you can assemble a plumbing system amazingly quickly using PVC pipe. (You can cut the pipe with a saw, but it is time consuming and messy.)
- Long Lasting. Even good quality hose only seems to last five years or so, but PVC pipe will last decades.
- Impervious to Most Chemicals. You can flush a PVC pipe system out with muriatic (hydrochloric) acid; the quickest and, as far as I know, only effective way to get rid of the scale that builds up in head discharge lines. Don’t try that with hose.
- Impervious to Odors. You can spend a fortune on sanitation grade hose and your holding tank system will still stink, but it won’t if you use PVC pipe.
One caution: We do not recommend PVC pipe for piping that is open to the sea and below the water line where a crack could sink you.
What do you use for piping that is open to the sea and below the water line, which most of the piping on our yacht is.
We use best quality wire reinforced hose.
PVC is vulnerable to diesel and UV light.
I use it below deck and over water line for cockpit and lazarette drains but not close to the engine or bilge. (even so, I never had diesel in the bilge)
Just make sure that you use CPVC for hot water piping. Standard PVC deforms at hot water temperatures.
I would refer to the ABYC standards before installing PVC, or ISO standards if out of North america.
After numerous disapointments with Bloddy epensive whiz bang hose, we were sick and tired of our holding tank stinking, so I replumbed with Thick wall pressure rated PVC pipe. Brilliant stuff, one of the most reliable systems on our boat now. We found its difficult to find any good pipe to hose joints at the time we built our system so we made ours using a hose barb and machined the threaded end of the barb to fit the ID of a pipe joiner fitting. The normal pipe was glued into the joiner which was in turn glued onto the hose barb, it was a little cumbersome but given we used as much PVC and as little flex pipe we only had a couple of joints like this and plenty of room in that area so it wasn’t an issue for us.
We have since had issues with the holding tank itself and as such have dismantled the piping but i was so happy with the quality and reliability of the system we will be installing the same type of fittings etc on our new boat.
For those that haven’t built using PVC at does take time and one of the best tricks we found was making pencil lines between pipe and joiner so we could assemble the new piping dry ing the boat and then take it all outside and glue it together in the fresh air knowing it was all perfectly aligned, as the glue can really stink the boat out.
Great tip on the pencil lines. We do exactly the same thing. On the pipe to hose barb, we found that we could get pipe to NPT thread adapters at a plumbing supply house and then just use a Maralon or bronze seacock tail pieces. One warning on this: the grey plastic threaded hose barb fittings typically available in plumbing supply houses in the US tend to be a bit oversize on the barb end and therefore do not work with reinforced marine hose.
Our boat has plastic pipes from new 1985.
Have noticed a few that were cracked and replaced it with rubber hose.
Was leaning against one pipe and it didn´t take much to break a 30mm
pipe, and since then keep a close eye on the critical ones and prefer to replace with good quality plastic hose where vibration is of a lesser concern.
Have had a problem to clean some drain pipes and plan to use a water and sand mixture and a low pressure hi volume pump. The sand collected in the tanks can be vacuumed out. Should only have to do this at most once a year. Have used this method at home without any problems.
That’s strange. Our PVC pipe plumbing is at about the same age and we are not having any problems. What grade and schedule of PVC pipe is it?
All I know it was a Dutch built boat, the pipe color is dark grey plastic, but will have a closer look when back on board. One time the feeder cooling pipe to one generator had broken off, without my doing………I think. So it appears its character does weaken over the years. Will do some ¨tests¨ on other pipes to find out the strength. Vibrations may have some negative effect and cause some kind of ¨metal fatigue¨?