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Author Topic: Fittings below waterline  (Read 2229 times)

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John Langford

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Fittings below waterline
« on: April 16, 2016, 01:18:23 PM »

I have just had what I think is the original elbow connecting my marelon thru hull to the output hose on the macerator pump split. Fortunately I am present and looking at it whenever the valve is open so there was no problem.

BUT, in the course of replacing it I realized that it was a PVC 1" barb to 3/4" female threaded elbow connected to a short threaded BRASS coupling connected to the Marelon valve. Looking at other thruhulls I found the exactly similar arrangement for the 1" ID galley sink drain. Also the elbow connecting the 3/4 shower/reefer drain to its thru hull is unreinforced nylon. Finally the fittings connecting the raw water filter to its input and output  hoses consist of ABC PLASTIC reducers and unreinforced nylon elbows or tailpieces.

From what I understand of ABYC STANDARDS, PVC, ABS and nylon are verboten below the waterline and all of the above thru hull setups are below the waterline. But my boat had its first insurance survey recently and the surveyor said nothing about any of this.

Some questions:
Are the above arrangements common to all MK IIs?
Are my concerns about the materials used misplaced?
Has anyone else tried to redo these arrangements using marelon elbows, tailpieces and reducers?
Does anyone know if the big black raw water filter is marelon or is it a heavy plastic knockoff?
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Cheers
John
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KWKloeber

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Re: Fittings below waterline
« Reply #1 on: April 16, 2016, 02:20:07 PM »

I've posted on here before about this.

CTY is NOTORIOUS for using NON-COMPLIANT, big-box store gray, pvc fittings at critical locations below waterline.  I've seen it over and over and over and warn each customer about this -- oftentimes pvc is hidden at the sea water intake.  Some care, some don't care and never change them. The main problem w/ pvc is, it cannot withstand the side pull test and the threads deform and whammo."

One issue is, there's not Marelon available for all situations / thread / hose combinations -- and of course marine bronze is expensive -- so CTY prefers to supply us non-compliant, crap pvc.  BUT of course, "This not a design or manufacturing flaw or substandard materials or anything that CTY should be expected to stand behind and install correctly because owners can always get at them and change them themselves."  And, since other boat mfrs may do a worse job, CTY is well within it's rights to use them.  Plus the general feeling is that we love the design other aspects so well, it's not really a big deal if CTY knowingly installs a potential sinking flaw.  Hell there's always insurance.....   :twisted:

Usually these are schedule 80 pvc fittings, but (OEM) I had SCHEDULE 40 pvc on an unused 1-1/2" head thru hull.  Besides being a no-no, no-no (pvc, and Sch 40) it is an ABSOLUTE NO NO NO to use a female NPT thread (like CTY did with a sch 40 cap) on a straight thread (NPs) thru hull.  I won't go into the engineering reasons why not here -- just trust me on this DON'T DO IT.  EVER.   :!: :!: :!:

if anyone wants to correct the pvc's -- You can get to me offline if you like and I can set you up (there's many different configurations so it;s not that "standard" a fix.)

ba boom (jumping off the soapbox)

Cheers
Ken
« Last Edit: April 16, 2016, 02:20:32 PM by KWKloeber »
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Paulus

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Re: Fittings below waterline
« Reply #2 on: April 17, 2016, 04:02:54 AM »

Ken, why don't you post the correct pvc? John might not be the only one interested in this topic. John asked a legitimate question of general interest to all of us.  Let's not hijack the topic. 
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KWKloeber

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Re: Fittings below waterline
« Reply #3 on: April 17, 2016, 10:12:06 AM »

Hijack?  Bite your  tongue man!  JTSO - I think that characterization might be better worded.
The previous answer addresses the question/issue, but I'll re-post.


To wit:
Quote
Some questions:
Are the above arrangements common to all MK IIs?

CTY is NOTORIOUS for using NON-COMPLIANT, big-box store gray, pvc fittings at critical locations below waterline.

Even on newer boats.

Quote
Are my concerns about the materials used misplaced?

The main problem w/ pvc is, it cannot withstand the side pull test and the threads deform and whammo."
Usually these are schedule 80 pvc fittings, but (OEM) I had SCHEDULE 40 pvc on an unused 1-1/2" head thru hull.  Besides being a no-no, no-no (pvc, and Sch 40.) 

PVC is NON-COMPLIANT, period.

Quote
Has anyone else tried to redo these arrangements using marelon elbows, tailpieces and reducers?
Does anyone know if the big black raw water filter is marelon or is it a heavy plastic knockoff?

(there's many different configurations so it's not that "standard" a fix.)

"standard," "typical," and "usually" are not in boat manufacturers' vocabularies.  If they were, something as simple (right?) as running a cable from "A" to "B" would be "Answer C," and could by every DIY C34 owner.  That's not a criticism of manufacturing because there's oftentimes constraints during manufacturing that are unknown to the end user -- it's just reality boat owner need to deal with.

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Read between the lines.  Liability.

To cover every situation I'd need to write a 10 page TW article or a matrix of every boat thru-hull/hose/strainer/sea water/engne configuration:
     * If you have A and want to do B, then buy C.
     * But if you have D and A, then buy E.
     * Or if your boat doesn't have a strainer, do F.

Additionally, there's a wide range of owners' knowledge and abilities and interpretations, and I said before there's not one fitzall answer. Case in point -- "post the correct pvc" -- after I said PVC is non compliant.


So to publish a half-answer, or if owner-X follows half a recommendation, but not all of it, because s/he doesn't have necessary knowledge or ability that maybe owner-Y has -- might end up as a disaster.  So, I can't suggest a specific substitution that affects human health on a vessel where it's not a known one-on-one situation.  Examples - I've tried helping people who apparently couldn't get the sense of the need to remove a hose and fitting to send a pic of what was below it -- to see what was proper to replace it with.  Done -- outta there. 
Conversely, I've helped a DIY-er who spent a grand on a custom product from a top-line manufacturer, only by happenstance asking for a pic just F.M.Info -- luckily I saw that both the owner/manufacturer screwed up on a "basic, boating 101, common sense, everyone knows this", hazard --  stopped him from installing it -- and saved a bundle of cash.  (not to mention averting the human hazard.)  And as I said that was an "everyone know this" situation.  So to publish a fitzall solution for a human health hazard concern would be foolhardy and could, at best, be misinterpreted by DIYers.

There's not one sole answer -- as I said.  There's not a marleon nor marine bronze available for every situation -- but one would think there would be.  And even if there is one for a specific application, the product may be crap.  Well known national brand xyz is an example -- its supposed marine fitzal hose elbows and hose barbs (say for a sea water pump) sounds good -- fits 1/2 or 5/8 hose, bronze, NPT, nearly long enough (if you are very very careful) to be double clamped below the waterline -- so YES it works on a 5/8 intake hose -- unless, of course, you want full flow -- because flow area is like a 3/8" fitting.  Some configurations are best changing a hose size (and then maybe the pump fitting, and not just replacing a sea cock tailpiece/hosepipe.

Otherwise, my "emphasis added" was to DRIVE HOME that (even tho the forum does a great job making most known) more often owners end up missing or taking these deficiencies lightly, maybe because CTY obviously takes them lightly.  Wrong fittings can be a disaster but maybe not the worst.  At least sinking doesn't normally cause an electrical fire (and take out your neighbors as well.)

kk
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
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Paulus

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Re: Fittings below waterline
« Reply #4 on: April 17, 2016, 11:57:37 AM »

Ken, now that you had me bite my tongue and reading your post for the 2nd time.  Can I use marelon above the waterline.  Want to replace the thru hull fitting for my anchor locker?  This sometimes is in the water depending on the heel of sail.
I have replaced my galley sink thru hull with a bronze thru hull(1'1/4) so that my galley sink would drain and not plug up.(up grade a few years back. 
Thanks, Paul
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KWKloeber

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Re: Fittings below waterline
« Reply #5 on: April 17, 2016, 12:02:52 PM »

Ken, now that you had me bite my tongue and reading your post for the 2nd time.  Can I use marelon above the waterline.  Want to replace the thru hull fitting for my anchor locker?  This sometimes is in the water depending on the heel of sail.
I have replaced my galley sink thru hull with a bronze thru hull(1'1/4) so that my galley sink would drain and not plug up.(up grade a few years back. 
Thanks, Paul

Theoretically yes.  But it's best to pics  - There might not be a marleon that's available for the size or configuration.  There might be another alternative that works as well. -- are you talking replace the thru hull or just the hose fitting above - size and type - what's there?

Ken
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Paulus

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Re: Fittings below waterline
« Reply #6 on: April 17, 2016, 12:50:25 PM »

I want to replace the thru hull, the hose and the small fitting inside the anchor locker. 
Paul
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KWKloeber

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Re: Fittings below waterline
« Reply #7 on: April 17, 2016, 01:02:23 PM »

I want to replace the thru hull, the hose and the small fitting inside the anchor locker. 
Paul

I don't remember what's inside a C-34 locker.  Need pics, hose size, straight or 90, thru hull size, etc.  bla bla bla.


thx
Ken
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Ron Hill

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Re: Fittings below waterline
« Reply #8 on: April 17, 2016, 02:42:15 PM »

Paul : I believe that the anchor well thru hull is a 1/2" barbed fitting.  I got one (marelon) at Boat US a few years back when they were a chandlery (so they are made). 

A thought
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Paulus

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Re: Fittings below waterline
« Reply #9 on: April 17, 2016, 03:49:05 PM »

Spring as arrived here in Michigan.  I will check it out on Tuesday.
Thanks, Paul
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