Rigid Piping

[Michael O'Hara]

In another forum (not HOW) I've seen some discussions regarding replacement of sanitation hose, and there seems to be a recurring belief that rigid piping (e.g. PVC) would be best for us lake sailors since the flexing of the boat systems would be minimal (compared to ocean sailing) and the PVC would not permeate odor.Seems to me that ANY flex in the system is asking for a leak.... at least.Your thoughts?Thanks, as always!Michael O'

 

[Ed Schenck]

But a hybrid could work.

The idea was also discussed here on HOW with comments from Peggy. Long runs where you could use a straight piece of well anchored PVC would be fine. But then make final connections with flexible hose clamped to the PVC. However most boats do not have straight runs for anything to anywhere. And I know many lakes that will flex a boat.

 

[Peggie Hall/Head Mistress]

Ed's right...It has to be a combination

Hard pipe should never be directly connected to anything else "rigid"...'cuz any shock or stress--even banging the dock hard--will put stress on the connection and can crack the weaker side of it. A hairline crack in rigid PVC may not allow liquid to escape, but it certainly will allow odor to escape. And when it's connected directly to a holding tank, it's almost always the welded fitting in the tank that lets go, not the pipe that cracks. So it's necessary to "soft couple" any hard pipe with about a foot of hose to act as a shock absorber when connecting to a toilet, thru-hull, pump or tank. And, as Ed mentioned too...it's ok for long straight runs, but there aren't many of those on boats. Every bend requires inserting a radius fitting, which mean cementing a union into it...and every union becomes a 'bump' in the pipe to trap bits of solids and paper.IMO, hard pipe makes sense only on boats large enough to have 6-8' straight runs (much longer than 8' and the tank is too far from the head anyway)...not in any other circumstances.If you'll tell me what site the discussion is on, I'll be glad to drop by and answer questions.

 

[Michael O'Hara]

Thanks!

Appreciate your opinions! (As always!) The forum thread was a while back on the Pearson 28 owners site. I'm in process of re-routing piping but will use all flexible sanitation hose, no rigid PVC. I'm more "curious" than anything else, 'cause I see on other forums (not just P28's or HOW) that other folks have a lot of success with practices that I wouldn't try and that you, Peggy, have cautioned against. E.g. bladder holding tanks,Wesson Oil lubrication in the toilet bowl, etc.Thanks again for ALL your great advice!Michael O'

 

[Peggie Hall/Head Mistress]

"Success" is a relative term

It all depends on how you define it, and what you're willing to accept. To some, "no odor" only means none INSIDE the boat (their downwind neighbors may have a different opinion)...or odor reduced to a tolerable level. Some would rather pour something down the toilet once a week than take the pump apart once every two years. Most don't recognize that a toilet is gradually becoming less and less efficient, only outright failure...so "success" is defined as something that's appeared to be working THIS season. Next season or the one after may be an entirely different story, but for now it's their "sucess story"...and they prob'ly won't connect the failure with their "successful" solution to what was causing it.I tend to avoid "band aids" in favor of permanent--or at least long-term--solutions to problems...recommend preventive maintenance instead of only "fix what breaks"...solutions to problems in one part of the system that don't negatively impact the rest of the system (something else that even equipment mfrs overlook). I've found that approach not only results in fewer problems, but actually costs considerably less.