concerns about plastic seacocks

[Fred Ficarra]

OK, Almost ALL of my favorite people are on this

thread. Let's go back to our respective corners and come out with a smile. And Henk, I'm sure what you say about tires is true, BUT, Firestones' problem was Management. They suffered from old school greed. The first scandal was a textbook case. The second, well, like I said, they are old school.

 

[Tom S]

Here's somethingelse, Go to your local chandelry

and pick up a bronze Groco thru hull and then pick up a Marelon Forespar thru hull. You will notice the bronze thru hull side walls are much thinner than the Marelon. Not that the bronze is less strong, but more likely the Marelon is over engineered with thicker walls to remove the possiblity of having problems with manufacturing like Henk was mentioning.One downside I see is that the Inside Diameter of the marelon is noticably smaller (due to the thicker walls of the thru hull) and in smaller diameter thruhulls the reduced water flow might be a tad less. Most applications this wouldn't matter.

 

[John Nantz]

Comment for Tim re

Tim - re your earlier post "My only doubts about Catalina..." and how long the Marlon valves will hold up. I'd like to pass along my personal experience with Marelon and bronze for what it's worth. Way back when (in the "olden days" as my daughter calls them) all good boats had bronze valves and that's what I grew up with. Around '87 the C&C 36 that I crewed on was sinking in the San Juans and the owner asked me to fly him up there (I told this story before and it's in the archives) and the problems was a bronze thru hull that basically fell off due to corrosion. The majority of the corrosion was from the inside where it couldn't be seen. The owner was the lead Mechanical Engineer in my office and really new his stuff. This guy was detail oriented and had a flow rate curve for his engine water pump (GPM vs RPM). I know because after we installed a new bronze valve we tested it using his graph. My boat is a Hunter Legend 35, 1988, and it came from the factory with 6 Marlon valves. Needless to say I was a bit concerned about the valves when I was thinking about buying her but the years went by and no problems. Then, about 12 years or so later the one under the sink had a problem with the handle - it twisted off. I had the yard replace it and received some maintenance information that came with the new valve to read. Up until that time I had done ZERO maintenance on the valves. There was nothing in the original boat manual about specific maintenance except to "inspect for leaks frequently" (ref page IV-2 of Manual). The boat is now 15 years old and so are 5 of the 6 valves and they are all still working, albit with some maintenance now(!), and this is with the boat always in salt water. There has been virtually zero electrolysis. Statistically, given this record (15 years, no maintenance for 12, one broken handle due to lack of maintenance), I feel very confident about their reliability.Also, I took the old valve, the one that came out of the boat, and beat it first with a 20 oz framing hammer and then with a small sledge. Results: some cosmetic scratches on the "plastic". I was impressed.If I had any concerns what so ever it would be more with the radiator hose clamps that hold the hoses on and not with the valves. On the other hand, after trying to remove one of the hoses that doesn't bother me now, either!!! (that's supposed to be a joke). P.S.1. I have no financial interest or connection with either Forespar or any company related to Marelon.2. My boat manual now has two full pages (8-2/2 x 11) covering the subject valves and their maintenance.

 

[Tom S.]

John N. thats the same experience I had

Like I posted before when I got my boat, I thought about wanting to replace my "plastic" (Really I know them to be Marelon) thru-hulls.Someone who knew better than me said go to the store buy a Marelon thru (I think it was less than $10) and wack it with a hammer and try to break one. As discussed before this stuff is really tough, like your experience just nicks and scratches. I'm sure if I took a bronze thru-hull the same size and hit it as hard and as often it would have been badly dented and distorted. Just remember to get REAL Marelon thru-hulls because the problem is most chandlries carry both .

 

[Chris Burti]

Share!!!!!!!!!!!!!

Please share those two pages with us.

 

[John Nantz]

Share Problems w/ Copyrighted Information

Chris - it'd be great if I could publish the information, the two pages, but I'm positive it's copyrighted. I'm not going to dig into where I got it to check but it was either off a document that came with the Marelon valve, off a Forspar web page, or from one of their catalogs.The portion about maintenance is available at the web site via a link that was previously mentioned, either in this particular original post or another one recently at: http://forespar.com/resources/tips/MarelonLube.htmInstallation: http://forespar.com/resources/tips/MarelonThruHullSeavalveInstallation.htmPlumbing section: http://www.forespar.com/catalog/plumbing/plumbing.htmSeacock dimensions: http://www.forespar.com/catalog/plumbing/seacock.htmA lot of what I have is more-or-less covered by the above links and their paper catalog.

 

[Gord May]

My Apologies to Henk

I did not intend to imply that Henk’s motives, in questioning the specified tests, were in any way nefarious. I should have merely added the details (missing from my original post (in the interest of brevity), that I thought illuminated the questions he raised. I have, unsucessfuly, tried to delete that portion of my post.My apologies Henk - I regret the implications of my words.By way of explanation: I don’t know Henk, but understood from his post, that he had some command of the subject of materials & testing - expertise that I would have thought would provide the basis for a reasonable assumption about the methodology to be employed in meeting the specified values (when used in technical "standards"). Apparently, Henk felt that mere numbers can be misleading, unless their origins are explained. He's right.Sheepishly - my Regards,

 

[henkmeuzelaar]

No hard feelings at all, Gord !

I know all too well that analytical chemists like me can be a royal pain in the neck; never trusting any labels or manufacturer's claims. The makers of Marelon appear to have played it very close to the vest and have been careful not to make exaggerated claims. They better not or Dupont might at some point yank the Zytel supply from under their manufacturing operation. As the company with the proverbial "deep pockets" Dupont always has to be on the lookout for liability issues. When the first artificial hearts -- made largely of polyurethane -- were implanted in human patients here in Utah, Dupont decided to yank their polyurethane supply from the company making the special solutions for implantation research.The small company affected decided to buy a load of pantyhose made from the same Dupont polyurethane (i.e. Lycra Spandex), dissolve them and clean the solution up for use in artificial heart research. How do I know that? One of my most talented students spent over a year unraveling that story in the laboratory after we noticed that one of the two artificial heart chambers recovered from Dr. Barney Clark after his death had different polymer additives in it. Fortunately, this fact did not seem to have affected the clinical outcome and my student got a nice MS thesis out of it.Nah, from all the first-hand testimonies Marelon sounds like a good product. With my retirement coming up soon, though, I still need to make good on a promise to Peggy Hall to analyze the presumed witches brew made by the LectraSan devices. If anyone plans to send me some effluent from their LectraSan, please carefully double-tape the containers or I am going to have trouble with our mail delivery room ;DHave fun!Flying Dutchman

 

[Russell]

Some marelon seacocks had a design defect....

Marelon seacocks often are two or three pieces held together by stainless steel bolts. On one model, the bolts threaded directly into the marelon base. While marelon is strong, it isn't hard. As the boat jostles in waves, the stainless threads eat away at the plastic threads, until the marelon threads are stripped. Then the seacock starts to come apart. It really gets a sailor's attention to see water spraying from between the pieces of a seacock that is slowly coming apart. I don't know why I didn't think to take a picture of all the faces at the moment -- probably because mine had the same dumbfounded expression. Forespar will replace these seacocks with a newer model that has metal inserts to receive the bolts.