440: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old.

[Lagoon4us]

Originally Posted by goboatingnow

while in theory this is correct, theres an awful lot of it floating around well in excess of 5 years.!


Dave

Yer that's very true, i guess at the end of the day you deal with possible scenarios, we all have experience of seeing de-zincafication on old brass screws hence in the bin they go.
As a few have said prior there are no internet links to the loss of a boat by these valves/fittings.

We are happy the valves we have chosen have been tested and are suitable. I will be adding a clamp to ensure side load doesn't stress the fitting.

Cheers.

[goboatingnow]

We are happy the valves we have chosen have been tested and are suitable. I will be adding a clamp to ensure side load doesn't stress the fitting.

and at the end of the day thats all that matters "We are happy"

[Watercolor]

With regard to real seacocks, not Ball valve/thru-hull combinations, I agree with Jedi, if you have to have a hole in your hull, do it right. A true flanged seacock, thru-hull and backing block are the best insurance for you and your boat.

On a bronze thru-hull, the wall thickness is about .10” and that .10” is compromised by the fact that the threads are machined (notched) as opposed to cast or molded. The seacock housing and base distribute both static load stress and the base when used with a backing block and lag bolts diminish the potential effect of impact and shear on the thru-hull.

Take a look at Mainsail’s testing on a variety of thru-hull/valve combinations. Mainsail did an excellent job at documenting his efforts and he recognizes they’re not perfect. They do, however, raise some real flags with regard to the ABYC standards we now have. Several on this thread have provided valid criticize the ISO standards.

Something many of you might not know is that the reason for Mainsail’s tests. He had a situation where a spare alternator broke loose and seriously damaged a thru-hull/ball valve unit, in particular the thru-hull. Because there is no ABYC impact test, so he used the static load test.

I feel the real questions and debate should be:

What forces (groups, etc,) have moved us from real bronze seacocks to, in the case of European standards, brass ball valves and thru-hulls? In the ABYC’ case it’s move from real seacocks to ball valves and thru-hulls. And what information was used to make those changes. Additionally, who and what influenced the standards as they now exist?

The other question is really, what are boaters willing to accept by way of testing and characteristics desired in seacocks and thru-hulls?

With bronze we have an known issue regarding corrosion, it’s easy to identify and straight forward in it’s solution. Plastics are another matter. They don’t corrode; they degrade, some plastiics more than others. And it’s not as easy to identify the degradation level. In fact, most “experts” seem to give the plastics a pass.

So with bronze, it’s simply replace ASAP. With plastics, all you really have is: (is it breaks it breaks), or what the % of degradation level is over time. What % of degradation would you find unacceptable for a plastic thru-hull on your boat? Are there other known issues like impact that should be tested and what should the criteria be? Is there a bottom line for you, like PVC thru-hulls and ball valves should not be on boats?

If it wasn’t for the insurance issue, there are quite a few boaters who would be happy with PVC. As they say, “I’ve never had a problem with PVC seacocks (ball valves) in the 20 years I’ve used them.”

I’ve always felt that Murphy and his laws were on steroids on a boat, and tried to act accordingly.

[Watercolor]

Lagoon4us - Yesterday at 1:51 you posted a comment with the reference , the first two lines were:

"Watercolour, In the Lagoon Forum there's endless rabbiting comment regarding the skin fittings that are installed by BENETEAU as the builder.

This history of vehement critique that at times went quite personal was largely the work of 'trolls' and idiots."

[Lagoon4us]

Exactly and if you were part of the prior threads/discussions you would understand where the comments came from, NOT from Lagoon owners but the armchair brigade, you missed the point totally, do you have a Lagoon or indeed a Beneteau?

The reason for this thread was to give Lagoon owners another choice, do you seriously think we haven't seen it all before? Do you believe GROCO'S are the new kid on the block that must be largely unknown to us?

Seriously if you want a discussion start a thread that specifically considers the knowledge you wish to impart.

Cheers

[NahanniV]

Originally Posted by Lagoon4us

Seriously if you want a discussion start a thread that specifically considers the knowledge you wish to impart.

Cheers

What was your intent in starting this thread ? Perhaps you should have stated the rules

It seems that you have the same concerns as me with regards to the strength of your valve assemblies. Your plan to attach the valves to the hull is one way to mitigate that issue, but I think it might be simpler if not cheaper to just choose a stronger valve/skinfitting system like a forespar 93 or other seacock.

How is your test progressing ?

Cheers,
JM

[Lagoon4us]

My intent was to share with Lagoon owners what one Lagoon owner has decided to do with regards to replacing 5 year old valves of poor original supply.

I share no such concerns with you regarding lack of strength, my methods are methods i've applied through my boatbuilding life.

The Nylon 6 component is soaking still however it seems results have been pre-empted due to temperature, it seems the soggy cardboard effect is only achieved if the waters warm.. Who would'a thunked it???

[Lagoon4us]

I soaked two items, first one is the back up washer supplied with the skin fitting it is made from pure Nylon 6 as far as i know. 'The washer is more pliable.'

Dimensions:-
Before After
OD 52.63 52.80

ID 34.18 34.24

THICK 2.54 2.58

Second item the backing nut from the skin fitting.

Across flats (smallest of 3) 42.04 Nil change yet.

OD 52.23 " "

Thickness 13.06 " "

Cheerz......

[dirkdig]

I think i will be doing the same as Frank, his years of boatbuilding are much better than my 15 minutes of ownership.

So once again i am confused?
What metal do we use for thru hulls and valves?

[downunder]

Originally Posted by dirkdig

I think i will be doing the same as Frank, his years of boatbuilding are much better than my 15 minutes of ownership.

So once again i am confused?
What metal do we use for thru hulls and valves?

A good place to start if going metal.

Compass Marine "How To" Articles Photo Gallery by Compass Marine at pbase.com

[dirkdig]

Very informative,

[s/v Jedi]

Aha! And here we have the test for bronze fitting and valve:
(Failure at 400lb)

http://www.youtube.com/watch?v=YzKb0rm56Zk

[minaret]

Since everyone seems to be using Maine Sails tests, here is a link to the results of all these tests in one place, with his opinion on this issue. It's definitely a carefully crafted and valid opinion too.


Strength of Seacocks, Are Yours Strong Enough? - SailboatOwners.com

[Lagoon4us]

A ball valve hung off a full length skin fitting is an incident waiting to happen. However Beneteau do this as normal practice, i think the items are 'store drawn' and installed by labourers, as long as they don't leak all is acceptable in their respective QA.

Any valve needs support not only for impact but stress and unthreading/loosening by the hose itself due to movement by vibrating/shifting etc.

Any test of a threaded ball valve screwed to a skin fitting should be done with that valve mounted correctly i.e. fastened/saddled/strapped to the hull/bulkhead or whatever with the skin fitting trimmed to suit the hull thickness. The videos show an out of the box skin fitting untrimmed, however it's a wake up call for people to look and check if their valves are installed correctly. Bet not many are!

To do so other wise is not a real test of the true ability of the fitting as a metal boat will have say a 6mm thickness as against a planked timber hull which could have a 2 inch (50mm) thickness.

This hull thickness difference impacts on the length the skin fitting will hang out, resulting in increased or decreased leverage when the unit is stressed.

Whatever valves you install, do it properly, think about the 'what if's'.......

Cheers

[Watercolor]

Lagoon4us – I’m surprised that you found that much difference in only 7 days. Nylon 6 and 66 are quite hydroscopic. The 7day figure I used in my question related to a Dupont 66 product, 101. Actually, the number of days to saturation was 9, but at 73 F. That was with a thin section of material. At first I thought the temperature where you are would be higher, hence the 7 day estimate. In the Caribbean 7 days would probably be very accurate. Again, please remember that I was only asking a question, not trying to present facts.

My guess is that you’re seeing what some refer to as “blooming” of the nylon. Not sure if that’s a technical term or not. The parts were exposed to the ambient humidity, which my guess is close to 75% or 80% on your boat. So the nylon 6 part was near that level of saturation. And when you immersed it in water the outer surfaces just took on the water quickly. It might be a month before the part reaches full saturation. If you take the part out of the jar and keep it in as reasonably dry place as possibly for a couple weeks, then test it. It will likely have return to equilibrium of the ambient humidity of your boat and you’ll see it return to it’s earlier size. On a boat in salt water, the issue, according to some literature I read is that the nylon absorbs both the water and salts. The salts don’t seem to completely leach out and might cause some permanent degradation.

As I mentioned before, the key factors on how much and how quickly nylon reaches saturation are: thickness of the part, amount of humidity the part is exposed to prior to immersion, temperature, the type and treatment of the resin, and fillers like rubbers, glass beads, mica which do a lot toward reducing the moisture absorption but decrease the overall strength of the part strength. Glass fibers help decrease moisture absorption and increase strength. However, the trade of comes with the conflict between the resins elongation and the glass fibers rigidity, especially when saturated.

The other part, is it the same as the thru-hull and the valve? If it is then all bets are off, you may not see any change for months, it may take the heat of high summer to see any change, but I’m quite sure it will change. One way you might get a sense of things is to take one of the thru-hulls and screw it into the ball valve (tightly) take a metal object that will resonate, a butter knife might work. And strike the ball valve, not super hard, if it’s over 30 to 40% glass it should sound glassy. My feeling is that the glass fiber content is around 15 to 20%, especially after seeing the static load test picture Ed Griffin provided. The apparent bend in the unit, at dry as molded, is telling.

There’s a lot more to this issue. If you’re interested I’d contact TRUDESIGN and get the EMS spec sheets on the material they use for the thru-hulls. I mentioned them in an earlier post.

I’m not “anti-plastics” but I am pro-safety.

Here are the full run of videos that Mainsail produced. To me they were most informative.

Seacock Load Test #1 - YouTube

.be

Seacock Drill & Tap - YouTube

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

Forespar OEM Series 93 Seacock - ABYC Load Test - YouTube

Failed Seacock - YouTube

Drilled & Tapped Groco Flange Adapter With 3/4" Marelon Valve - YouTube