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PEX vs Reinforced PVC

Discussion in 'Ask All Sailors' started by Ward H, Dec 7, 2018. Add this thread to a FAQ

  1. Ward H

    Ward H

    Joined Nov 7, 2011
    1,972 posts, 281 likes
    Catalina 30 Mk III
    US Barnegat, NJ
    I have original 1/2" reinforced PVC hose for the fresh water system on my 93 C30. I'll be scrubbing clean the two water tanks and thinking I might as well replace the 1/2" hose as most of it is looking pretty funky.

    I read a little about PEX hose and wondering what the advantage was to using PEX vs reinforced PVC hose. Cost? Quality? Ease of Install?

    Any suggestions?
     


  2. Justin_NSA

    Justin_NSA

    Joined Jul 7, 2004
    5,059 posts, 915 likes
    Hunter 30T
    US Cheney, KS
    The PVC hose is probably more "bendy" than PEX. Is there a complete line of fittings to work with like PEX?
     


  3. NYSail

    NYSail

    Joined Jan 6, 2006
    1,870 posts, 126 likes
    Beneteau 423
    US Mt. Sinai, NY
    Not having read much about the application on a boat, I would think PEX would be the way to go..... In regards to the fittings, I know its not totally advisable for behind wall application, but based on the low pressure of our boat systems, the "Sharkbite" fittings they sell at HD might be nice as well.... again I have done no research on the topic, just my thoughts.

    btw Beneteau used a PEX like piping for the hot / cold water lines that I am so far very happy with.

    Greg
     


  4. rgranger

    rgranger

    Joined Jan 19, 2010
    5,617 posts, 1,267 likes
    Hunter 26
    US Smith Mountain Lake
    About 8 years ago, I replaced ALL of the copper pipe in my house with PEX.
    Love it! You need to buy the crimping tool and it is not that cheap. But with the proper crimping tool PEX is fast, easy, reliable and versatile. Got to get the tool. So if you are only doing a small job, there may be better choices. You have to do the cost/benefit analysis.
     


  5. Justin_NSA

    Justin_NSA

    Joined Jul 7, 2004
    5,059 posts, 915 likes
    Hunter 30T
    US Cheney, KS
    +1
    I have crimped all my own fittings at home and never had any problems. My Zurn set was just over $125
    [​IMG]
     


  6. dlochner

    dlochner

    Joined Jan 11, 2014
    2,816 posts, 1,205 likes
    Sabre 362
    113 US Fair Haven, NY
    If you go with reinforced hose, avoid hose barbed connections to fixtures and use standard SS supply tubes. Like these https://amzn.to/2UpRsnl Much easier to make the connections.
     


  7. Scott T-Bird

    Scott T-Bird

    Joined Oct 26, 2008
    3,571 posts, 635 likes
    Starwind 27
    US Barnegat, NJ
    I think the crimping tool is the way to go if you have a large number of fittings because the shark bite fittings are quite expensive. If you have just a few fittings, shark bite fittings will save you the expense of the crimping tool. I used the shark bite fittings and found on the suction side of the pump, the 1/2" PEX with a few 90 degree bends was a significant flow limitation. I changed the suction side out to 3/4" reinforced hose to solve that problem. I recommend PEX for the pressure side of the pump and hose for the suction side. If you need to snake the line through some bends on the suction side, you will do better with smooth curves rather than 90 degree bends and the PEX is not that flexible. Like David said, I used the flexible SS faucet connectors for connections to the pump and fixtures.
     


  8. Scott T-Bird

    Scott T-Bird

    Joined Oct 26, 2008
    3,571 posts, 635 likes
    Starwind 27
    US Barnegat, NJ
    Ward, what size are your tank fittings? I screwed up with the PEX installation at the tank when I did mine. I have a 3/4" male threaded fitting made on the tank, so when I put on 1/2" PEX I needed a reducer, and it was a significant reduction. Remember, the 1/2" PE is outside diameter. There is only about 3/8" I.D. - much less than the 1/2" hose. That's barely enough to pee through at the suction side. The pump has 1/2" fittings, so that's what suckered me into installing the 1/2" PEX originally. Combine that with 2 - 90 degree bends, and I barely had any water flow and the pump made an awful racket because it couldn't suck the water out of the tank. When I changed to 3/4" flexible hose, my problems went away. I only needed an adapter for the 3/4" hose to 1/2" faucet connection to lead into the pump.

    BTW, on the pressure side, you can buy a flexible faucet connection to thread onto the pump fitting and it has shark bite connection on the other end for the PEX pressure plumbing system. It worked very well for easily connecting PEX to the pump with a removable and adjustable lead.
     


    Last edited: Dec 7, 2018
  9. Chris Patterson

    Chris Patterson

    Joined Oct 17, 2011
    2,784 posts, 69 likes
    Ericson 29
    US Southport..
    I completely replumbed a Cheoy Lee with PEX a couple of years ago. The owner specifically wanted the quick connects, (shark bite, whatever), and I wasn’t crazy about it. No problem though, if the owner has the money, I’ll cut it in half and make it ten feet longer if he wants. Anyway.....putting it in was one of the easiest jobs I’ve ever done, and I’ve plumbed a few boats. Snap together man.
    The ends are a tad pricey, thereabouts of ten bucks apiece. He wanted the ability to take it apart and add or replace something down the road, (and after three years hes not added or replaced anything).
    But it doesn’t leak. This is an ocean going boat, just returned from a pounding going to Bermuda and back. So I’m sold I guess. I wouldn’t hesitate to use it again..
     


    rgranger likes this.
  10. Justin_NSA

    Justin_NSA

    Joined Jul 7, 2004
    5,059 posts, 915 likes
    Hunter 30T
    US Cheney, KS
    Sharkbites are magical. The same fitting can take PEX, copper, PVC and CPVC tubing. And with a simple tool will release the tubing without damage to fitting or tubing. You pay for it though. If the system design is stable, crimps are much cheaper.
     


  11. Hello Below

    Hello Below

    Joined May 7, 2012
    541 posts, 48 likes
    Hunter e33
    CA Maple Bay, BC
    I have only had a couple of times where I needed to disconnect PEX fittings. It is one time I can honestly say "the job was easy" and really mean it.
    HOWEVER, this summer we had a leak at the input to the transom shower box. Not a failure of the PEX fitting per se, but at the threads on the cold water inlet nipple. The angle of the rigid tubing was way to tight and put undue force on the connection, and resulted in a small leak. It was then that I realized that there was no way to isolate that line (or any other water line on the boat) except to turn off the domestic water pump and therefore remove pressure throughout the whole system. I now have several End Stop fittings that will allow a portion of the system to be isolated when needed..
     


  12. LeslieTroyer

    LeslieTroyer

    Joined May 20, 2016
    2,027 posts, 777 likes
    Catalina 36 MK1
    US Everett, WA
    It’s interesting early Catalina ran reenforced pvc from the tanks to the water pump. Then transitions to PEX. I might do pex for all and put in a tank manifold valve.
     


  13. Rick D

    Rick D

    Joined Jun 14, 2008
    6,630 posts, 185 likes
    Hunter Legend 40.5
    US Long Beach, Shoreline Marina, CA
    [
    HOWEVER, this summer we had a leak at the input to the transom shower box. Not a failure of the PEX fitting per se, but at the threads on the cold water inlet nipple. The angle of the rigid tubing was way to tight and put undue force on the connection, and resulted in a small leak. It was then that I realized that there was no way to isolate that line (or any other water line on the boat) except to turn off the domestic water pump and therefore remove pressure throughout the whole system. I now have several End Stop fittings that will allow a portion of the system to be isolated when needed..[/QUOTE]
    As an aside, this is a common issue with 90's Hunters. While the angle may contribute to it, I think there is simply vibration and a mis-match of materials contributing to it. I had this happen (leakage) several times over the last 20 years, even replacing the shower assembly. The last time, I got uncomfortable with the cockpit shower not having a way to isolate the feed lines, so I purchased shut-off valves and placed them upstream from the shower. Now, I only turn on the cockpit shower when I am going to use it. Problem solved. See these valves available from ACE on-line: https://www.acehardware.com/departments/plumbing/valves/globe-valves/46854
     


    Last edited: Dec 7, 2018
  14. HMT2

    HMT2

    Joined Mar 20, 2014
    600 posts, 142 likes
    Hunter 31
    US Shoreacres, TX
    PEX is great but make sure you keep it covered. It does not handle UV well at all. (According to my plumber that ran PEX throughout my house)
     


  15. Scott T-Bird

    Scott T-Bird

    Joined Oct 26, 2008
    3,571 posts, 635 likes
    Starwind 27
    US Barnegat, NJ
    I would use this faucet connector to eliminate that hard connection that doesn't quite line up. It provides flexibility and a valve.
    https://www.amazon.com/SharkBite-24...hvlocphy=&hvtargid=pla-4583520382301870&psc=1

    If you are going to use PEX from the tank to the pump, I would use 3/4" PEX. At least it is greater than a true 1/2", not smaller. Also, I would avoid 90 degree bends and try to sweep the PEX through any turns that need to be made.
     


  16. Hello Below

    Hello Below

    Joined May 7, 2012
    541 posts, 48 likes
    Hunter e33
    CA Maple Bay, BC
    Great idea Scott, thanks. Athough many Hunters and other manufacturers use metric PEX (15mm) tubing vice the standard (1/2") I am sure there exists an equivalent item or items in metric.

    Now that is something that is going on the project list. Thanks Scott. Now I have to consider whether to use standard sizes (3/4") from the tank to the pump or stick with metric (22mm). Hmmm. The latter would give me more volume/
     


  17. Ward H

    Ward H

    Joined Nov 7, 2011
    1,972 posts, 281 likes
    Catalina 30 Mk III
    US Barnegat, NJ
    Scott, the hose barb off the tank valves is 1/2”. Not sure of the fitting size. Defender has a line called Sea Tech which sounds like PEX hose and Shark Bite fittings. Their hose chart shows the ID of the hose. Makes sense to up the size of the intake side.

    PEX sounds like a good way to go.
     


  18. LeslieTroyer

    LeslieTroyer

    Joined May 20, 2016
    2,027 posts, 777 likes
    Catalina 36 MK1
    US Everett, WA
    Personally I like copper rings vs push connections, just seems more secure.
    Les
     


  19. LeeandRick

    LeeandRick

    Joined Apr 26, 2015
    436 posts, 158 likes
    S2 26 Mid
    US Lake Havasu
    It's always amazing how a certain way to do things morphs on these forums. I've made the first comment several times and turned the whole thread in my direction. I'm replacing the fresh water system in my 44 year old boat this month and went back and forth on PEX vs what has lasted for 44 years. I'm going to boil out the fittings and replace the hose with new and will be dead by the time it needs to be replaced. It's a substantial cost and effort savings that I will spend on beer :beer:. Nothing against PEX but why reinvent the wheel. KISS!
     


  20. JanErik

    JanErik

    Joined May 4, 2018
    18 posts, 6 likes
    Catalina 25 SV
    Pon Farr US Colorado

    You don't actually need the tool to release the Sharkbite fittings, you can use a wrench and just push-in the fitting...its easy.
     


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