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Old 01-03-2013, 14:28   #91
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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Originally Posted by s/v Jedi View Post
Well, I have one Forespar Marelon 3/4" thru-hull fitting + seacock which on MS test got to the 500 lb for only a second or so before the flange disintegrated. I will remove it with the next haul-out and replace it with the Groco flanged adapter etc. It did heldup very well over the years but then again it never saw any stress applied to it.

Same with my Vetus seastrainers. Out they go en Groco goes back in. All because of this thread
If it's this test you are referring to:

Seacock Drill & Tap - YouTube

Don't forget that there was no through-hull/skin-fitting installed, I think the total assembly with the through-hull would have easily passed.

Cheers,
JM.
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Old 01-03-2013, 14:38   #92
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Originally Posted by NahanniV View Post

If it's this test you are referring to:

Seacock Drill & Tap - YouTube

Don't forget that there was no through-hull/skin-fitting installed, I think the total assembly with the through-hull would have easily passed.

Cheers,
JM.
Yes, that may well be the case, but the flanged seacock is supposed to keep the sideloading forces off the thru-hull fitting. I also didn't like how that Marelon thru-hull fitting broke off at the mushroom head in the other test.

I still have these above waterline for which they are okay to me; others use PVC there...
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Old 01-03-2013, 17:08   #93
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

I saw the full set of tests Mainsail did, and they were interesting to me from a plastics and molding perspective. I talked to Mainsail for quite a while about the parts he was using, including ambient temperature and humidity they were in. There's a lot going on in Rob's tests that simply isn't visible.

My guess is that the mushroom head broke of because it was the weakest point on the thru-hull. That may seem obvious, because that is where it broke. But normally, all things being equal, it should have broken at the intersection of the locking nut and the thru-hull just like the bronze thru-hull did. The threads are usually the thinnest part and they're right at the fulcrum of the level arm.

So why did it break at the mushroom? The material Forespar uses, called Marelon, is simply a Dupont glass filled nylon with some rubber filler for impact resistance. Nylon elongates and since this part was old and saturated it stretched putting added stress on the mushroom/shaft area. This intersection of mushroom and shaft is molded in a sharp 90 degree angle. Not the most ideal plastic design for a potentially stressed part. Ideally the angle intersection should be slightly rounded. Hence, the failure. Also, the more moisture the greater the elongation, the greater the loss of strength.

The other issue was, as Jedi mentioned, the flanged 849 seacock failure. Again, my guess after conversing with Rob (sorry, Mainsail) is that this part was also old and well saturated. This contributed to the failure. However, the way the part came apart suggests a potential plastic flow issue that could extend through the size range. Again this is only speculation, but this is a thick section of the flange. It's possible that the gating is insufficient for the volume of material being injected. Another possibility is that the part being thick was not provided enough time to cure before being taken out of the mold. All of this could cause weakness in the part. If I were going to provide parts for the ABYC static load test, I'd make sure the seacock batch that UL picked from was carefully monitored to insure it was right up to molding spec.

NahanniV is right about the thru-hull adding strength to the fitting.
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Old 01-03-2013, 20:46   #94
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Dirkdig - You asked, "What metal do we use for thru hulls and valves?"

My experience is with US seacocks. All the US metal seacock manufacturers use bronze and some stainless steel. Regarding stainless it should be 316 stainless. It appears most people in the know (AKA experts) chose bronze over stainless.

Bronze gets a little confusing. The bronze US seacock manufacturers use is called composite bronze or 85-5-5-5. 85% copper, 5% tin, 5% lead, 5% zinc. It also goes by the name leaded red brass. And it's now most common name is Alloy 836 which comes in two ASTM categories: (a) continuous (like rod) ASTM B505, or (b) sand cast (B62).

The basic reasons the manufacturers use 85-5-5-5 is that it has good corrosion resistance, is reasonably priced and, because of the lead, is quite machinable.

In Europe, there seems to be a lot of marine parts made of DZR brass. DZR - dezincification resistant brass. It's basically brass (63% copper and 35% zinc pls a few other metals). My understanding is that the final product is put through a heat and chemical process (arsenic?) process that creates a hardened copper surface. If you decide on that material look for the DZR on the part. I believe the British Blake seacock is DZR.

I'd try and find a seacock that you're guaranteed is 85-5-5-5 or Alloy 836 through-out. And stay away from mainland Chinese metaled fittings.

Hope that that helps.

Fair winds
Thanks Watercolour,
I will order from the states if i go bronze for ball valve replacement and hose barbed ends too
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Old 02-03-2013, 00:52   #95
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

It's interesting that commercial vessels in Australia for valves under 50mm in diameter and not below the LWL by more than 230mm do not require seacocks.

Vessels under 1D, 2C and 3A Classification are not required to have metal piping valves etc whereas above that class all must have metal.

There are no test requirements for fittings no matter the class.

Our vessels are not Commercial so we can do better than this standard, the standard is USL which is the base standard accepted by AMSA.

Cheers
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Old 11-06-2013, 04:00   #96
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Hi Frank,

About to do the same with our 440,
Any big reason to go stainless hose joiners instead of the trudesign ones?

Thanks Peter
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Old 11-06-2013, 04:12   #97
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

If you are looking at the engine ones you have to weld spigot on to get the size needed, check out and you'll see what i mean.

Hey something to check on yours, ours is a three cabin version and the port-side aft cabin sewage outlet is forward of the seawater inlet for the toilet so if you are at sea or in isolated anchorage where you leave the outlet open and waste goes directly to sea it actually re-circulates!!!!

Dumb as dogshit these designers! Check yours, next time we slip i intend 'T' piecing the front portside toilet water inlet and blanking the aft one, both crappers will never be used at same time.

Viv would complain of brown water coming into the bowl, the raw water filter for the toilet was full of corn and wheat (don't know why we bother eating that stuff) so for days after you strain through a pooied filter!!!!

Pretty basic stuff
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Old 11-06-2013, 04:59   #98
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Was just thinking about the barbed ends being stainless v's the plastic ones?

The recycling of brown water is an issue, i never got the benifit of eating corn either.
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Old 11-06-2013, 05:09   #99
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

Choices were made based on what was available at the time, the engine hose to the filter is quite large.

Surprisingly the ball valves i removed that had been in salt all their life are in perfectly good working order so much for the intelligent condemnation by the 'know it alls'???

Cheers and good luck.
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Old 11-06-2013, 05:15   #100
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Mine still work ok too,but look poor extenally in spots.

Doing the bottom shortly so i figure on replacing the valves at the same time.
Enjoy Europe its freezing in Melbourne.
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Old 11-06-2013, 05:19   #101
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

Thanks it's 33c here the Lithiums are charged by 1pm then maintain the boat's draw from then on.

The nylon seacocks haven't expanded since being immersed so i can still get into our cabin ok and i haven't needed to use them for a cleat or kedge off so no side loads have occurred.... All sweet!

Oh yer and Corfu and Paxoi are quite nice too

Cheers Frank
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Old 11-08-2013, 03:01   #102
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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Attached pictures of the complete kit of valves needed to be replaced as part of maintenance on a Lagoon 440.

At 5 years old i want to know the ball valves are in very good condition hence the effort.

Total cost for all shown is around AUD 600:00.

I chose Kiwi 'TRUDESIGN' units they are IMCI Certified ISO 9093-2. Material is Glass re-inforced Nylon 6.

I had to make a 316#SS Adaptor for the engine cooling (VOLVO) as the pipe jumps up in size to accomodate the filters.

Also i've included 3 more valves to convert the sinks in the bathrooms to drain straight overboard instead of going through the shower drain, pump filter and pump on it's journey. It's just dumb to waste valuable amps to drain a sink that's above the LWL!!

We will slip in Greece and install there.

Cheers.
Hi,
I have a 440 and would like to replace all the thru hulls as the boat is now 6 years old, could you email me the complete list you purchased with the sizes and types you used and where you to source from, much appreciated.
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Old 11-08-2013, 08:14   #103
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

Hey Huggi i bought the Tru-design valves through http://www.biasboating.com.au/Search...?mfg=TruDesign

I have no list at hand as all that is back in Australia and i'm in the Cyclades at present.

Cheers Frank
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Old 14-08-2013, 01:45   #104
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

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Hey Huggi i bought the Tru-design valves through http://www.biasboating.com.au/Search...?mfg=TruDesign

I have no list at hand as all that is back in Australia and i'm in the Cyclades at present.

Cheers Frank
Hi Frank, Thanks for getting back, I am after the head outlet valves as these seem to be needing replacement, any chance you could take a look at yours as I am in UK at the moment and my boat is in St Lucia and cannot find out the size, or would the shop in Aus still have the list.
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Old 14-08-2013, 02:03   #105
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Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

Our holding tank outlets were in very good condition, they are a form of plastic seacock of brand that i do not know of.

They are a 90deg skin fitting with a valve incorporated.

The raw water supply valves to the sink and toilets were of brass/bronze construction they were simple ball valves, the skin fittings were bronze of proper construction.

No BIAS is a mail order company, i added valves to drain the sinks in the heads directly over the side in lieu of draining to the shower sump. Also we have 'chilled water' air-con that required valves that you probably don't have likewise the de-sal inlets.

Each boat is fitted with different valves according to the original purchasers order so really every boat differs. The raw water inlet for the engines is through the leg so there's only a valve on each motor to cut supply.

You should be able to get anything delivered to St Lucia that you need once you confirm what you need, i can measure the sink valves, engine supply and toilet inlet but the rest could be any size they saw fit for your boat.

Cheers let me know.
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