TruDesign fittings

[sailingharry]

A bit of a rant, a bit of a question. I have numerous above waterline thru hulls that are badly oxidized, and need to be replaced. I also have a 3/4 Marelon where the handle is broken (old style, not fixable). So I have about $200+ in parts to order. TruDesign has a single distributor in the US -- Gemlux.


So, first, the rant. They don't actually sell "TruDesign." 100% of their product has been rebranded to Gemlux. Some (the valves) are clear. Some not so clear. For instance, they sell two 90 degree thru hull tailpieces (1.5" female thread to 1.5" hose). One I am fairly confident it is TruDesign -- it LOOKS like it. The other is also glass filled nylon, but it has NPT threads -- and TruDesign makes NO NPT threaded fittings. If you are trying to buy TruDesign, you have to be REALLY careful on the Gemlux website.


Second, an installation question. These thru hulls are naturally NPS. I really don't understand NPS. How does it seal? TruDesign talks about it. They support pipe dope or teflon tape (but don't recommend it), saying it will seal -- but how? But, they also go on to say that it doesn't make a rigid assembly, especially if you use a 90 degree outlet (I will be). They strongly recommend 5200 for installation of the thru hull as well as sealant on all threads. 5200 is obviously a HUGE red flag! Is this really the right material? Is something better? In 20 years when I need replace it again, will I seriously regret using 5200? Thoughts? I hate to admit it, but I'm kind of leaning toward 5200 -- anyone know where to buy it (just kidding -- but I've never bought it in my life!).

[peghall]

Raritan distributes TruDesign products...the link to them on the Raritan website is broken but they'll come up along with the retailers who carry them if you google "Raritan TruDesign."


--Peggie

[Bowdrie]

Originally Posted by sailingharry

For instance, they sell two 90 degree thru hull tailpieces (1.5" female thread to 1.5" hose).

Be careful with those 90 fittings.
Murphy dictates that a 90 fitting will NEVER point in the direction you want.
The only 90s that were ever worth a d**n were the bronze ones by Wilcox-Crittenden, (long discontinued,) or in the present day by Spartan Marine.
They use a swivel female thread.
https://www.spartanmarine.com/all-pr...adapters-parts
The Groco IBVF is the cat's meow for all replacement of seacocks unless you spend a fortune on the "Real Seacocks" made by Spartan.

[Toccata]

I have used Trudesign (skin fittings, ball valves and hosetails) for complete changeouts in the last 4 boats. (11m thru to 15m yachts and motorsailers, with multiple fittings.)
Great product imho. No corrosion. Note; I have always used the collars to add extra support to the skin fitting.
The local shipwrights' recommendation is a polyurethane (in our case Fixtech 15) sealant.
It "sets", but is removable. It has a bit of bulk for thread filling. It allows orientation of a loose 90 deg fitting and will hold it in place.

[sailingharry]

Originally Posted by Bowdrie

Be careful with those 90 fittings.
Murphy dictates that a 90 fitting will NEVER point in the direction you want.

This is high on the list of why TruDesign recommends 5200 for thread sealant -- you don't have to get it tight, and once cured it never moves.


They also argue that while 5200 is permanent, when and under what conditions will I ever want to move a thru hull -- and if I want to replace it, it is trash anyway so take it out with a saw.


But its 5200... I'm not sure I can do it....

[sailingharry]

Originally Posted by peghall

Raritan distributes TruDesign products...the link to them on the Raritan website is broken but they'll come up along with the retailers who carry them if you google "Raritan TruDesign."


--Peggie

Thanks Peggy. That almost helps. The Google results are a bit rambling, but at least I found a few more sites. Unfortunately, the 3/4 ball valve is all but vanished from the North American continent. I may call Raritan tomorrow, and see if a telephone helps.


Raritan claims to have an exclusive distributorship in the US, but TruDesign only lists Gem. Wonder if that's part of the problem -- a shift in distributor arrangements.

[s/v Jedi]

When you are in the US you can simply use the good Forespar series for plastic or Groco for bronze.

https://defender.com/en_us/forespar-...room-thru-hull

[stormalong]

I've used 5200 as pipe dope but if you are worried about it use 4200. Just as good for the purpose and a little easier to remove.

All of my thru hulls and seacocks are Marelon from Forespar. Great valves, zero maintenance. A few are still original in my 1985 boat. I have replaced many just because they did not have the flanged version back then and I like the added strength.

[GordMay]

Originally Posted by sailingharry

...
Second, an installation question. These thru hulls are naturally NPS. I really don't understand NPS. How does it seal? TruDesign talks about it. They support pipe dope or teflon tape (but don't recommend it), saying it will seal -- but how?...

NPS = National Pipe Straight [parallel], per ANSI/ASME B1.20.1
Straight Pipe Threads need a gasket, or O-ring, to create a good seal.
Even taped or doped, NPS threads won't produce a pressure seal.
5200 will produce a [somewhat] pressure-tite seal, depending upon how many threads are engaged.

[Benz]

5200 is my goo of choice for nearly everything. Embrace the 52.

[sailingharry]

Originally Posted by GordMay

NPS = National Pipe Straight [parallel], per ANSI/ASME B1.20.1
Straight Pipe Threads need a gasket, or O-ring, to create a good seal.
Even taped or doped, NPS threads won't produce a pressure seal.
5200 will produce a [somewhat] pressure-tite seal, depending upon how many threads are engaged.

Indeed, Gord! That's the connundrum. All thru hulls are NPS, and they better seal tight! Now, one can argue that the seal is between the mushroom and the hull on the outside, and the valve body and the hull on the inside, and the threads don't need to seal. But at least for TruDesign, the threads are NPS on the outlet as well -- and there is no gasket or O-ring to seal. Tru-Design supports, but does not recommend pipe dope on these threads.


It gets even worse on a thru hull connected to a threaded hose fitting (I'll be using several of these). There is no place for any gasket or O-ring of any sort, and they won't touch the hull to make that a seal. So they will rely 100% on the "sealant" in the threads.


To be honest, my installation is already non-ABYC compliant. I have 7 of these that are well within the "heeled water line" and 2 more that on a bad day are under water, and none have valves. Even worse, I have 2 bilge pumps and a shower sump that discharge below the heeled water line with the high point below a common (but still somewhat extreme) heeled water line. I agree this is bad, but the solution is rather significant. It's been that way for 24 years, and I am unaware of any Sagas that have sunk for these issues.

[Ryban]

I believe indeed the TruDesign fittings rely on the the adhesive (either 5200 or sika 291) to provide sealing, and there's a requirement for how many threads need to be engaged.

TruDesign doesn't use NPT on the top of the fitting because they claim it's an unreliable way to create a seal compared to adhessive applied to NPS threads, but maybe that's only true for composite fittings, and not so much for bronze.

[sailingharry]

A small twist on the project. I figured all the above water thru hulls were crap plastic. None had visible branding. Turns out that is not so.

* I pulled the first, a 1" fitting. In pulling the hose off, the tail broke off in my hands. Got the stub out, and it has "PERKO" on it. Yeah, crap plastic. Glad to be upgrading.

* Then I went to the 1.5". No branding, but a rectangular raised spot that used to be branding. Can't get the nut off (it's in 5200, I assume). But can't break it off -- I wiggled and pulled and then put it off for another day. Then I was looking at the next boat over, and that rectangular spot says "MARELON." YAAA! That means that 3 of my 7 -- all the 1.5" ones -- are Marelon.

So, the question. Perko is crap, as I see. Marelon is good at 26 years old. Are Marelon on their last legs, and I should replace them, or is Marelon a lifetime product and unless something goes bad, they never need replacement?

I have a note into Forespar, waiting to hear their thoughts.

[s/v Jedi]

Originally Posted by sailingharry

A small twist on the project. I figured all the above water thru hulls were crap plastic. None had visible branding. Turns out that is not so.

* I pulled the first, a 1" fitting. In pulling the hose off, the tail broke off in my hands. Got the stub out, and it has "PERKO" on it. Yeah, crap plastic. Glad to be upgrading.

* Then I went to the 1.5". No branding, but a rectangular raised spot that used to be branding. Can't get the nut off (it's in 5200, I assume). But can't break it off -- I wiggled and pulled and then put it off for another day. Then I was looking at the next boat over, and that rectangular spot says "MARELON." YAAA! That means that 3 of my 7 -- all the 1.5" ones -- are Marelon.

So, the question. Perko is crap, as I see. Marelon is good at 26 years old. Are Marelon on their last legs, and I should replace them, or is Marelon a lifetime product and unless something goes bad, they never need replacement?

I have a note into Forespar, waiting to hear their thoughts.

I would replace them so you have everything new. At 26 years old, they have performed beautifully. There’s nothing bad about Marelon except that paint falls off. I think the TruDeaign fittings are a similar material; it’s simply fiber reinforced plastics.

Have you considered bronze? A Groco bronze fitting with their flanged adapter is affordable and good for life. For a wooden or fiberglass boat there’s nothing I could come up with against it.

[jcapo]

Use one of these on the NPS threads and some Rectorseal. Solves the positioning problem.

https://gemlux.com/collections/compo...-1-5-nps-black