Marelon Seacock fail!

[Ralph Johnstone]

Chemours, the manufacturer of Teflon did not recommend to me that I use their product so why would I say that their product failed.

Missed the part where the mfg. warned you against using teflon tape. Did they give you a reason for steering clear of teflon tape ?

 

[Hayden Watson]

Missed the part where the mfg. warned you against using teflon tape. Did they give you a reason for steering clear of teflon tape ?

Teflon did not have any comment because they were not consulted by me. I do not know if Marelon contacted them.
My point was that Teflon should not be blamed because it was not their advice.
To blame Teflon for the Forespar recommendation of their product would be akin to blaming Ralph Johnstone for failing to warm me against using plumbers tape in spite of the fact that I never asked him for his opinion prior to the installation.

 

[thinwater]

White was probably the wrong product. Should have been pink or yellow. Pink and yellow tape are thicker and better seal larger , coarse threads. More layers of white does not solve the problem. MOST DIYs use the wrong Teflon tape.
wiki re. tape
On land, in most areas, using the wrong tape is a code violation and you'll get to do it over. Certainly, you will on gas and fuel applications.

• White: used on NPT threads up to 3/8 inch
• Yellow: used on NPT threads 1/2 inch to 2 inch, often labeled "gas tape"
• Pink: used on NPT threads 1/2 inch to 2 inch, safe for potable water
• Green: oil-free PTFE used on oxygen lines and some specific medical gasses
• Gray: contains nickel, anti-seizing, anti-galling and anti-corrosion, used for stainless pipes

I use a lot more yellow than white.

 

[Hayden Watson]

White was probably the wrong product. Should have been pink or yellow. ..

And I have yellow for a gas line I needed to relocate recently.
Never know the difference between them and never saw any colors other than white and yellow until this week.
What would you suggest for a paste sealant that would work in a damp condition?

I have a collision matt in the cockpit locker and was thinking about seeing how well it might work. I will position it over the thru-hull and then open the valve with a hose to the bilge to see if it will seal up. The PO was paranoid about sinking and installed a 2000gph primary bilge pump and a secondary 4000gph mounted higher on its own switch so there is no problem with seeing if the matt will seal at least down to a trickle.

 

[Ward H]

Hayden, you mentioned you used G Flex epoxy externally, one of the reasons given was it stuck to plastic. Do you feel it will hold the thru hull well enough to allow removal of the valve?

 

[Ward H]

Poor instructions and the assumption that folks are experienced. They probably assume that most are pro installed.

I did find it interesting that the Forespar website lists the valves under Marelon/Pro Valve Series.

 

[Hayden Watson]

Hayden, you mentioned you used G Flex epoxy externally, one of the reasons given was it stuck to plastic. Do you feel it will hold the thru hull well enough to allow removal of the valve?

The 4000uv should be enough to hold the thru-hull in place. The G-flex is added insurance. The mushroom head and the gelcoat recess were both sanded with 80-grit. West system has an add showing a kayak being glued back together with G-flex.
This is the actual thru-hull that I used.
Forespar 931153V | Fisheries Supply

 

[Ralph Johnstone]

What would you suggest for a paste sealant that would work in a damp condition?

The big boys use teflon tape with a light smear of Permatex #2 for cold applications. Don't see why it wouldn't work on steam as well. How much steam do you have on your boat ?

 

[Hayden Watson]

The big boys use teflon tape with a light smear of Permatex #2 for cold applications. Don't see why it wouldn't work on steam as well. How much steam do you have on your boat ?

View attachment 199695

No steam unless the impeller comes apart or the heat exchanger plugs up.
I was referring to the fact that if I pull the seacock off while the boat is in the water with just the collision matt, there will likely be a small amount of water coming through the thru-hull so none of the fittings will be dry.

 

[Ralph Johnstone]

while the boat is in the water with just the collision matt

Never heard of a collision mat before. Very neat. If it weren't for the hefty tag, I'd get a few for the idiot power boaters around me. Don't know if they're smart enough to take the hint.

there will likely be a small amount of water coming through the thru-hull so none of the fittings will be dry.

Now it's time to get inventive if not downright nutso.

Seeing as how the thru hull is a straight thread, I would really encourage you to use a mix of both tape and paste sealant as mentioned in post #5. Any paste that's compatible with the plastic will be fine. As far as tape goes, steer clear of the coloured tapes. They are thicker than the white tape and I can tell you from installing all the steel gas lines in my house, yellow tape DOES NOT stick well to threads due to the extra thickness. Use lots of wraps and don't force it. Your work will not be seen by an inspector.

You're going to need a relatively large amount of "material" in those straight threads to effect a seal as opposed to an NPT match.


1. Install the collision mat as best it goes.
2. If there is a female thread in the top of the valve, insert a full sized male NPT X tube adapter, just finger tight. If there is NO female thread on top, get up, go grab a beer and say "to hell with it, maybe tomorrow".
3. Install a clear vinyl tube to the adapter (so that it's above the water line).
4. Open the valve and see how the crash matt holds.
5. Remove the valve if the leakage is tolerable.
6. Ram paper towel as tight as you can down the thru hull fitting to completely stop the water flow. Nobody said this was going to be easy.
7. You can now clean and work on both dry threads to your heart's content.
8. When you put the valve back on, screw it on WITH THE PAPER STILL JAMMED INSIDE. And no I'm not on drugs.
9. Remove the external mat.
10. Put the short length of vinyl hose back on the valve (if you took it off).
11. Make a sharp hook out of wire and proceed to go down the vinyl tube and fish the paper out of the thru hull. Maybe a fish hook on a wire clothes hanger. Now we're cooking.
12. Once the paper is out, finish with the rest of the tubing.

Even if you've got too much water and can't seal the thru hull with paper, hell, work with the threads wet and who knows, it just might work. If not, save it until next haul out. It can't be worse than it was.

All we ask in return is pictures, pictures, and more pictures.

 

[Hayden Watson]

I probably would not have bought the Colision Matt but given that the PO did I have been happily hauling it around with me in hopes of never using it but in this case, I hope that I can use it. It is in interesting design with the fabric weighted so that it sinks readily and is a water tight fabric.

Thanks for the well thought out sequence. Some of them will not apply and/or will need to be modified See highlighted comment below.

Never heard of a collision mat before. Very neat. If it weren't for the hefty tag, I'd get a few for the idiot power boaters around me. Don't know if they're smart enough to take the hint.



Now it's time to get inventive if not downright nutso.

Seeing as how the thru hull is a straight thread, I would really encourage you to use a mix of both tape and paste sealant as mentioned in post #5. Any paste that's compatible with the plastic will be fine. As far as tape goes, steer clear of the coloured tapes. They are thicker than the white tape and I can tell you from installing all the steel gas lines in my house, yellow tape DOES NOT stick well to threads due to the extra thickness. Use lots of wraps and don't force it. Your work will not be seen by an inspector.

You're going to need a relatively large amount of "material" in those straight threads to effect a seal as opposed to an NPT match.


1. Install the collision mat as best it goes. Both of the problem seacocks are of course directly amidships and to port of the keel. I will need to drop it on the port side and walk the forward line around the bow to the starboard bow and the aft line around the stern to the starboard quarter. After pulling both of these tight to bring the matt close to the keel I will tighten the port side line just enough to pull the matt up against the hull.
2. If there is a female thread in the top of the valve, insert a full sized male NPT X tube adapter, just finger tight. If there is NO female thread on top, get up, go grab a beer and say "to hell with it, maybe tomorrow". There are no threads on the top of the valve. These are 90º barb seacocks.
3. Install a clear vinyl tube to the adapter (so that it's above the water line). On this step, I plan to run a vinyl tube from the barb to the bilge. In order for the matt to work, it mush purge the water between the hull and matt which puts the outside of the matt at about 1.5' of head pressure. Given that 1 ATM pressure is about 14.7-psi and from Scuba I know that 2 ATM is at 33'. Therefor, the pressure on the matt is about 0.66-psi. I plan to run the water into the bilge to see if it will seal to a reduced flow. IF that happens, then I can proceed.
4. Open the valve and see how the crash matt holds. The crash matt needs to purge water to work. If it does not seal, I will leave it to run at a reasonable rate, controled by the seacock and fiddle with the lines to try to get the matt to cover the holes and seal.
5. Remove the valve if the leakage is tolerable.
6. Ram paper towel as tight as you can down the thru hull fitting to completely stop the water flow. Nobody said this was going to be easy. I can do this to apply the sealant but not to installe the valve.
7. You can now clean and work on both dry threads to your heart's content.
8. When you put the valve back on, screw it on WITH THE PAPER STILL JAMMED INSIDE. And no I'm not on drugs. This I cannot do. The paper towel would not be able to make the tight 90º bend at the top of the valve. I tried lubing these seacocks with Marelube using a straw to reach around the elbow as explained in the Forespar instruction and it would hit the end and not amount of fiddling would get it to turn the corner. Yet another Marelon instructional fail. I ended up going to the outside and smearing a bunch into them from the outside but not sure if it did any good. I will need to pull the paper towel out just before reinstalling the valve. It will not be anywhere as scary as pulling the knot/log impeller and replacing it with a plug so that I can clean the gunk off it between dives.
9. Remove the external mat.
10. Put the short length of vinyl hose back on the valve (if you took it off).
11. Make a sharp hook out of wire and proceed to go down the vinyl tube and fish the paper out of the thru hull. Maybe a fish hook on a wire clothes hanger. Now we're cooking. With the tight bend, nothing will go around the corner.
12. Once the paper is out, finish with the rest of the tubing.

Even if you've got too much water and can't seal the thru hull with paper, hell, work with the threads wet and who knows, it just might work. If not, save it until next haul out. It can't be worse than it was. Papillon has been out of the water exactly 4 times in the 23-years I have owned her. Not looking forward to a $300 haulout just to seal a stupid thru-hull so that I can enjoy my new perfectly dry LastDrop dripless packing.

All we ask in return is pictures, pictures, and more pictures.

 

[Ralph Johnstone]

I am finally understanding why you're so pissed with Marelon. I've never worked on a thru-hull on my own boat but finally appreciate that yours has a straight thread. Not having looked that carefully at your discussion of the thread type, I incorrectly assumed that because it had a flange, it would have an NPT thread like other bronze thru hulls with flanges.

Now that I have NPT out of my head, I would say that using teflon tape only on a straight thread is a recipe for disaster.

I limited my criticism of Forespar to their Marelon division because I have no beef with the rest of Forespar, just the Marelon tech and their written instructions.

The individuals responsible for the verbal and written statements regarding the use of teflon tape on straight threads need their collective asses kicked around the block at least once. I emphasize these were individual people who did not do their jobs and instead chose to quote inaccurate information to the public. Check with the professionals and see what they use for sealing NPT fittings on cold service. Then get their opinion on sealing straight threads on cold service.

Regarding the your current valve with the attached 90° hose fitting, that leaves me asking "why". Use a female NPT thread on top. It's downstream of the valve. Fix it if it leaks. All the attached fitting does is make it that much harder to get the valve handle and the hose fitting going in the required direction.

Hayden, this is not my problem and yet I find myself completely pissed with the load of crap you've been dealt whether written or verbal. I also find myself concerned that others will adhere to their inaccurate instructions. If I were to find myself in your position, I would demand the replacement of your present valve with one that fits your current thru-hull fitting and has a female NPT hole in the other end. This will allow you to proceed with the PROPER resealing of your straight threads or have them supply the money to pay for the haul out to do the repairs on the hard.

After hearing of your problem there is no way that I would ever consider purchasing any Marelon product. If ever questioned about Marelon products, I will be sure to mention the incompetence of their technical advisors.

 

[Hayden Watson]

I am finally understanding why you're so pissed with Marelon. ...

I do not figure that there is any way that they will do anything to make me whole. My hope in this thread has always been to bring the problems of the "approved mounting instructions" to the attention of others in our community so that through my pain, others can avoide pain of their own.

 

[Ralph Johnstone]

I do not figure that there is any way that they will do anything to make me whole.

I think you would do well to advise them of your disappointment in their lack of technical knowledge and send them the URL of this page. They can step up to the plate and show the world that they are prepared to back their customers or let you suffer from their mistakes. Good or bad, you will be reporting here what kind of an organization Marelon is when the mistake is theirs. What is Forespar's thoughts on this.


I don't think too many companies welcome criticism like this on the web.

 

[Hayden Watson]

So far, the tech email has been silent since I launched.

 

[jssailem]

Not surprised.
Send them a link to this thread. They are probably not enlightened as to the number of boat owners who may find this thread and decide the Marelon product line is not a good solution to their needs.

They will see their market share decline and blame it on things they see such as supply chain or marketing.

All the while the problem is internal .

 

[cagreen75]

After reading this entire thread I have to say that is important to know how these threads work. A quick google search for buttress threads will reveal how these threads are formed. They are cut with a taper on one side of each thread and a 90-degree angle on the other side of the thread, unlike a pipe thread that has the same angle cut on both sides of each thread. Buttress threads are not tapered like a pipe thread. When pipe threads are put together the tapered thread gets tighter and tighter the more it is tightened. Buttruss threads are not tapered and only seal when they are tightened down at which point the threads bind against each other over the entire length of the thread. Buttruss threads actually have a much larger sealing surface than pipe threads because they typically have a much longer thread. When a sealant is generously applied it tends to be carried along the entire thread and does not really seal until the threaded parts are pushed away from each other when the joint is tensioned to proper torque. When that happens the sealant is forced into the opposing thread over the entire length of the thread. Theoretically, the seal should be superior to a pipe thread joint. I'm not sure what went wrong in this case but I certainly hope that with all the feedback in this thread that Forespar will revise their instruction sheet to help installers understand how the buttress threads work and how to properly install the devices that they sell with them.
As an aside note, I have just ordered four of the series 93 Marelon valves for our Catalina 30. My plan is to fiberglass around the hole without closing it and before the resin sets push an appropriately sized tapered plug into the hole to create the taper needed for the flush fitting.
By the way, I never use just Teflon tape; it always gets backed up with pipe dope. Wish me luck!