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Old 25-02-2013, 04:32   #46
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Originally Posted by goboatingnow View Post

well thats eliminated virtually every production boat afloat, from HR and Oyster down.

in reality a bronze tr- hull and a backing board bonded in is way more then adequate and will see you to the boats end of life.
Dave
I assume you mean a flanged adapter or a flanged seacock? If so then yes, I agree. My "support behind the valve" was meant for the current situation or replacing this without a flanged part like OP.

I have no respect for the plumbing of thru-hulls of either HR, Oyster, Contest etc. and think all EU builders should study US components and practices on this particular detail of building boats. It is clearly one of the items that US builders are better at. Let me include sea strainers to that.
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Old 25-02-2013, 04:37   #47
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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study US components and practices
You mean the "one" thats left on the planet ( and blakes)


True bolted seacocks stem from the time of timber vessels, IN modern GRP, a decent backing board glassed in and good quality try-hulls in bronze are all that are needed to make a fitting that will last the lifetime of the boat.

Not all Europeans are using brass, ( though some are using DZR brass, some are using bronze)


Dave
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Old 25-02-2013, 04:40   #48
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Originally Posted by goboatingnow View Post

You mean the "one" thats left on the planet ( and blakes)

True bolted seacocks stem from the time of timber vessels, IN modern GRP, a decent backing board glassed in and good quality try-hulls in bronze are all that are needed to make a fitting that will last the lifetime of the boat.

Not all Europeans are using brass, ( though some are using DZR brass, some are using bronze)

Dave
No I don't agree. A decent backing board glassed in is to mount the flange on.
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Old 25-02-2013, 04:46   #49
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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No I don't agree. A decent backing board glassed in is to mount the flange on.
Thats OK, All of us are expressing opinions, when I see hard facts of boats sinking thats can be traced to non flange use, Ill examine them and if necessarily re-evaluate.

The backing board is there to (a) extend the hull thickness as that lends significant strength to the tru-hull by virtue of side wall support, ( mine are nearly 3" thick), (b) provide a bigger support area for the circular nut to bear down on and to spread the compression stresses.

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Old 25-02-2013, 05:05   #50
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Originally Posted by goboatingnow View Post

Thats OK, All of us are expressing opinions, when I see hard facts of boats sinking thats can be traced to non flange use, Ill examine them and if necessarily re-evaluate.

The backing board is there to (a) extend the hull thickness as that lends significant strength to the tru-hull by virtue of side wall support, ( mine are nearly 3" thick), (b) provide a bigger support area for the circular nut to bear down on and to spread the compression stresses.

dave
I think you ought to read the MainSail blog articles too, especially about material thickness around the threads. All the trouble that can be solved with a couple of bucks extra... people should take the better and easier road more often, instead of the rougher one.
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Old 25-02-2013, 05:20   #51
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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All the trouble that can be solved with a couple of bucks extra... people should take the better and easier road more often, instead of the rougher one.
I have read them , I have my own personal experiences as well. I have the opinion of many knowledgeable people I respect, I see no particular advantage in modern GRP boats to installing tru-bolted Groco style seacocks. ( nor are they just a "few bucks"). Nor is doing the backing pad, and tru-hull, "easier" , theres not much difference in effort.

The fact is Nick that its just opinion, as well engineered versions of each , will outlast the boat. We have no conclusive facts to dispute the performance of well installed bronze tru-hulls and bronze ball valves.

what we do have is that over the years, the number of boats afloat has risen by a large number and the suppliers of tru-bolted seacocks has dwindled to two.

"No point being the best buggy whip manufacturer in the world!"

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Old 25-02-2013, 07:15   #52
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Originally Posted by goboatingnow View Post
The fact is Nick that its just opinion, as well engineered versions of each , will outlast the boat. We have no conclusive facts to dispute the performance of well installed bronze tru-hulls and bronze ball valves.
You might not have the facts, but I have seen enough failures and emergency haul-outs to be convinced of it. Must have to do with the different areas we're in.

I can't come up with pointers but believe that insurance companies have reported that most sinkings are cause by plumbing failures like discussed here, instead of any other cause of sinking incl. collision. Boats sink because of failed thru-hull fittings all the time.

I do not recommend through-bolting the flange. I recommend to tap threads into the fiberglass backing block. In my case, I don't need backing blocks because my hull is very thick (cored) and with core replaced by epoxy with high density filler, I drill holes through the inner layer of fiberglass into the epoxy, and tap threads in that.

(to all) I also read that people think it's difficult to get fiberglass backing blocks... you can buy fiberglass cloth and woven roving everywhere, even in car parts shops. A simple quick lay-up takes very little time and is so easy, can be done under the boat in a yard in a flash.
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Old 25-02-2013, 08:34   #53
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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You might not have the facts, but I have seen enough failures and emergency haul-outs to be convinced of it. Must have to do with the different areas we're in.
I dont know, seawater looks mighty similar here


Quote:
I can't come up with pointers but believe that insurance companies have reported that most sinkings are cause by plumbing failures like discussed here,
Yes but not tru-hulls, usually plumbing fixtures further up the line , or by back siphoning, Sinking does require water to come in!.

Quote:
Boats sink because of failed thru-hull fittings all the time.
hyperbole, and opinion.

Quote:
I do not recommend through-bolting the flange. I recommend to tap threads into the fiberglass backing block. In my case, I don't need backing blocks because my hull is very thick (cored) and with core replaced by epoxy with high density filler, I drill holes through the inner layer of fiberglass into the epoxy, and tap threads in that.
Thats a great method, equally a good quality bronze try-hull , with several inches of hull depth so as to provide support, a backing plate and a circular nut screwed down will never cause problems either. The evidence is all around.

cheers

Dave
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Old 25-02-2013, 08:40   #54
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

Just to add to the plastic thru hulls debate... I owned a Gemini 105Mc for about 12 years. All thru hulls and valves are plastic, the type I do not know. What I do know is that after 12 years I had no a single problem. Operated the valves on a monthly basis to remove any marine growth etc. I now own a 440 2007 model, and she has just come up to 5 years old. I checked all the thru hulls and valves prior to purchase. All appeared to be fine with the exception of one where the plastic ball seal was lightly damaged (could be felt in the movement and a slight passing when closed) so I replaced with DZR. Just my opinions:.... I do think the suggestion of sink waste going straight over board is an excellent idea. I also think a lot of the content in this thread has been overly critical to an extreme to someone who is quite simply implementing what they see as a good idea and an improvement on stock fitting. Everyone is entitled to an opinion, but the loss of verbal control here is extreme. Let’s keep is informative and concise, not War & Peace, we have Leo Tolstoy for that.
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Old 25-02-2013, 11:04   #55
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

This is a very good way to test what metal your seacocks/skin fittings or any bronze type metal for that matter. Sand/polish the metal in question and compare. Copper Alloy Forms

Nick i'm glad you see my point regarding the crap Beneteau consider acceptable.

Cheers.
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Old 26-02-2013, 09:25   #56
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

Laghoon4us – Just had to respond one last time.

1. I’d be careful with your reference to your fellow Lagoon owners (past and present) whom you call “trolls and idiots,” the famous Danish Philosopher Soren Kierkegaard observed, “Once you label me you negate me.” Maybe those Lagoon owners aren’t quite the “trolls and idiots” you suggest.
2. “What i post is largely in the Lagoon Forum, my reasons are to inspire or assist others with Lagoon's.”
Until TRUDESIGN is willing to provide you with real information, I suggested you at least provide them with the following data related to a similar glass filled nylon product, Dupont Zytel 70G13L and let them make their own decisions.

Here’s the act Dupont data sheet,
http://www.valueplastics.com/technic...nformation.pdf and here’s a summary. I hope it comes across correctly this time.

Tensile strength (TS) Flexural modulus (FM) Elongation (EL)

Dry as molded TS 17,500 psi FM 700,000 psi EL 3
50% Relative Humidity TS 12,000 psi FM 400,000 psi EL 8
% Change (DAM to 50%RH) TS 31.4% FM 42.9% EL 167%
100% Relative Humidity TS 7,500 psi FM 250,000 psi EL 11
% Change (DAM to 100%RH) FS 57.1% FM 64.3% EL 267%

3. Ironically, Ed Griffin did provide some information about the TRUDESIGN material.

a. The TRUDESIGN thru-hulls sizes 1 ¼”, 1 ½” and 2” are the only ones that met the ABUC static load test. The ½”, ¾” and 1” fittings didn’t pass. This is the same issue Forespar had with their standard 849 thru-hulls. And that information seems to be missing from the TRUDESIGN website.
b. None of the TRUDESIGN products are UL 1121 certified.
c. The picture Griffin shows of the ABYC 500 lb static load test is quite telling. It appears that this test was done at the molding facility. Most likely to simulate a “Dry as Molded” (DAM) situation. As one can see the thru-hull is bent. This is due to the characteristic of nylon to elongate, see the data above. And this is in a “Dry as Molded” situation. At full saturation (the real world of boats), the elongation factor could be at least 267% greater. In that situation, it’s most likely the thru-hull would have broken or the weight would be on the floor.

This is consistent with the Dupont data.

3. As I said before, I’d love to see someone make a good non-metal seacock and thru-hull fitting. So far I haven’t seen any solid information to prove the case for glass filled nylon. The “never heard of a problem” is not real information, simply anecdotal. Forespar has used that ploy and search of the web shows that that’s not the case for both their 849 and 93 units.

Again, good luck on your project and fair winds.
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Old 26-02-2013, 09:33   #57
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.


1. I’d be careful with your reference to your fellow Lagoon owners (past and present) whom you call “trolls and idiots,” the famous Danish Philosopher Soren Kierkegaard observed, “Once you label me you negate me.” Maybe those Lagoon owners aren’t quite the “trolls and idiots” you suggest.


End of conversation with you, i have at no time called Fellow LAGOON OWNERS any such thing, CIAO Game over.
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Old 26-02-2013, 09:46   #58
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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Nick i'm glad you see my point regarding the crap Beneteau consider acceptable.
while in theory this is correct, theres an awful lot of it floating around well in excess of 5 years.!


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Old 26-02-2013, 09:47   #59
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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Originally Posted by NahanniV View Post
Have a look at this video:

Load Testing A 3/4" Marelon Ball Valve & Thru-Hull Fitting - YouTube

I suggest you try your own test: drill a hole in the middle of a 2' square piece of plywood, attach the skin fitting, put it on the ground, screw on the elbow valve and hose adapter, then step on the end of the hose adapter.

did it break? did it bend all the way down to the plywood ? seem strong enough ?

If the skin fitting breaks burn it and see how much glass reinforcement is in it. If none take them back to the chandlery.

I really think it would be a mistake to install those plastic skin fittings as shown in your picture.

Sorry,
JM.
I'm glad someone finally put an example together on what many of us have been saying for a long time. This video is a MUST SEE!
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Old 26-02-2013, 09:52   #60
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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I'm glad someone finally put an example together on what many of us have been saying for a long time. This video is a MUST SEE!
Exactly! Still, this thread shows how many find an install like in the video absolutely acceptable and deny the thin wall around the threads as a risk. The video shows that it breaks right there.

Forespar sells the same valve as a flanged seacock. It's a shame that this wasn't tested as comparison in this video to show the difference.

Glad I got flanged adapters and flanged seacocks
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