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

[Lagoon4us]

Yes they are informative and certainly apply to how Beneteau etal fit valves however they do not reflect good practice in boatbuilding. (Read my prior post)

The washer is simply Nylon, flexible and in the form of a soft washer.

The nut i have soaking is of the same material as the skin fitting, if i had a longer jar on board i'd soak the complete length.

It will likely be 2 to 3 months before we slip in Greece so it can sit in soak no issue. I'll do the 'tap the assembly test' on Saturday, i have gear to pick up and will not be aboard tomorrow.

[Watercolor]

Minaret - Didn't mean to duplicate your video efforts. I’ve talked to Rob (Mainsail) extensively. He is a very sharp and insightful person. Knows quite a lot about boats. He readily admits that his tests aren’t perfect.

There are a couple of things Rob’s test clearly show:

1. Elongation of nylon. The 93 thru-hull is seriously bent (the result of nylon resin elongation). It is most likely seriously compromised. Elongation is not an all or nothing visual. I believe this test was done at around 50% humidity. Think of what it would be at full 100% saturation. The test with the ball valve and Groco flange is another example of elongation and swelling. The part was old and well saturated more so than the 93. My feeling is that the ball valve housing simply deformed (elongated, stretched) and the threads were soft and had swelled (similar to Lagoons test) and simply let go. And POP.

2. One of the most interesting results was the Forespar thru-hull and ball valve combination. Contrary to the beliefs of some, the weakest point should have been right where the locking nut met the threads. The length of the thru-hull is not critical, it’s the length of the lever arm that’s really important. If Mainsail had put on a real tailpiece (on either the bronze unit or the groco/Forespar unit) and mounted the test line at the end, adding an inch and cut down the thru-hull by inch the lever arm would have been the same and the shear point would have still been at the locking nut. The locking nut position is also the weakest point on the thru-hull (or should be) since it the point of the thinnest material and the hull.

The fact that it broke at the mushroom surprised me at first, but I think the weakest point of that thru-hull was the sharp 90 degree angle ( molders usually round those angles) where the shaft and mushroom meet, combined with the elongation of the thru-hull may have shifted the balance point.

Please note these were only static load tests, not impact tests. An 8 lb loose weight on a boat can do ten times the damage of a 500 lb hanging weight. I agree with Jedi those exposed threads are a disaster waiting to happen. And Murphy loves those situations.

Fair winds

[Lagoon4us]

I think all miss the point, a properly installed valve in situ cannot be loaded in this way
in real life.

A properly installed unit has the following:-
1) The valve is positioned correctly with respect to it's use.

2) The skin fitting no matter the material is trimmed to minimum length to attain a seal and subsequent rotation of the next screwed fitting be it an elbow or valve.

3) The valve body is held firm to the hull or bulkhead by (a) A clamp. (b) a saddle (c) a 'U'-bolt.

4) If in a 'Traffic' area the assembly is boxed/protected.

The above as far as i'm concerned is all a given, i started this thread with the intention of step by step installation to assist other Lagoon owners, i do feel it's been somewhat hi-jacked, not so much about the ability of 'TRUDESIGNS' product to be suitable ie a Nylon Matrix of their formulation, but of physical/actual installation.

This thread has been inundated by supposition that my installation may be defective and that quite frankly is incorrect.

[Lagoon4us]

Have you looked at the picture in post 1#? Do you see the elbows? Do you understand my intention of saddling?
Then you post the following, which in my application does not concern my installation...The length of the thru-hull is not critical, it’s the length of the lever arm that’s really important. If Mainsail had put on a real tailpiece (on either the bronze unit or the groco/Forespar unit) and mounted the test line at the end, adding an inch and cut down the thru-hull by inch the lever arm would have been the same and the shear point would have still been at the locking nut. The locking nut position is also the weakest point on the thru-hull (or should be) since it the point of the thinnest material and the hull.

IF a six foot long pipe was part of the installation, guess what???

Everything posted here regarding strength supports WHY i'm doing what i'm doing because BENETEAU do it the incorrect way, the way depicted in each video and contained in your comments.

[neilpride]

Is not the way Beneteau install the fittings, this days many builders install the trhuhulls same way, is the material.

If we dont see any report of sinking boats due a brass roted fitting could be because the owner grab the roten fitting in time to save a disaster, anyway a frozen roted brass fiting can be broken trying to open and close it, is like a hole in steel hull covered with years of scale and corrosion , when is time to sandblast you see the holes and you wonder , heck!! i cross the atlantic with holes in the hull..

You can be ok with that plastic fittings, i have in my engine room 2 big size apollo trhu valves for draining the cockpit , everytime a mechanic or a intruder try to get there always put the foot and the body weight in the valve , thats why bronze work better in some situations .. Cheers...

[Watercolor]

I look forward to seeing pictures of your final installation.

Fair winds.

[Lagoon4us]

Cheers we are booked in Greece for end of May.

[Watercolor]

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

[Lagoon4us]

Quite amusing for those who have followed this thread, when i took over our Cat a year ago i read of so many criticisms of the way Beneteau/Lagoon did things and as a retired boatbuilder i naturally wanted our boat to be safe and correct in it's engineering.

When i joined the Forum i noticed a tendency for the old 'MONO Vs CAT' arguments with inane comment regarding other peoples choice of boats, at times in fun but at times PM's were being sent with distasteful comment. So much argument, quite often the moderators closed the thread.
It's interesting that not a single Multi Hull Sailor in the above post's wielding criticism!

Something the above 'posters' should clearly understand (the sewage holding tanks being the exception.) is that a 'bog standard Lagoon' has no seacocks!!!! I'll repeat HAS NO SEACOCKS


The engines (at least the Volvo's we have) draw their water up through the alloy leg and there is a BRASS valve leading to the plastic strainer. I defy anyone to fit a GROCO here!!!!

And why would you ever want to fit a valve of dissimilar metal to a 'Cast aluminium' Leg is beyond me? Beneteau have and that's why I'm replacing it with a composite. If the prior posters owned a Lagoon they would know this.

Only if you fit a 'De-sal', Genset or water maker do you come into needing skin fittings or valves. And a majority of Lagoon's do not have that luxury as they are charter boats..

Now let's continue with my thread in the light it was intended 'FOR LAGOON OWNERS'.

[Watercolor]

Lagoon4us - I'm interested in understanding what you suggest is the uniqueness of the Lagoon catamarans regarding thru-hulls, seacocks and ball valves. But first I feel I should comment on your statement, "When i joined the Forum i noticed a tendency for the old 'MONO Vs CAT' arguments with inane comment regarding other peoples choice of boats, at times in fun but at times PM's were being sent with distasteful comment."

First, the title of the thread is: "Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old." SInce I'm interested in learning more about cruisers perceptions about seacocks, ball valves, thru-hulls, both metal and plastic I decided to get involved. Had you said, "For Lagoon Owners" only, I still would have been interested in seeing what was so special about the Lagoons. This is after all the "Cruisers Forum", not the sailboat forum, the trawler forum, or the catamaran forum.

Second, I can't think of anyone on this thread that said anything negative about catamarans, Lagoon or otherwise. In all the time I've been on this forum I can't remember a time when there was a negative comment raised about catamarans. Not one.

Third, as for myself, I'd love to have owned a cat. However, my wife of 43 years is also an avid sailor and loves monohulls. So even though I tried, monohulls it was. Not that she disliked them, she simple preferred the sounds, motion and familiarity of the monohull.

I understand the issues of dissimilar metals and that sometimes, on a boat, unusual space constraints require special considerations. That I clearly get.

However, your comment, "(the sewage holding tanks being the exception.) is that a 'bog standard Lagoon' has no seacocks!!!! I'll repeat HAS NO SEACOCKS." I'm having a little trouble with. I understand that a straight production Lagoon, for what ever reason, uses a combination thru-hull and ball valve. And that the waste system uses a seacock.

My questions are: Is there any reason for that combination being the sole option for a Lagoon? (metal and unique space issues aside) I noticed the pictures submitted by Dirkdig and they seem to suggest that a proper seacock with an elbow tailpiece would work just fine in those locations. Your comments.

Also, is there a special reason why you would suggest that the waste system alone was a candidate for a proper thru-hull/seacock combination? Additionally, is it possible for someone buying a new Lagoon to special order (at a price)
the boat with US seacocks?

FYI - Sadly, the ABYC has chosen to, on it's own, redefine the term seacock to include a thru-hull and ball valve combination. However, when I refer to a seacock I'm talking about a valve (ball or cone) that has a bolted flange that attaches directly to the boat or backing plate and solid housing that accepts the thru-hull completely into the housing.

[Lagoon4us]

First, the title of the thread is: "Re: Replacing Skin Fittings And Ball-valves The Boat's 5 Years Old." SInce I'm interested in learning more about cruisers perceptions about seacocks, ball valves, thru-hulls, both metal and plastic I decided to get involved. Had you said, "For Lagoon Owners" only, I still would have been interested in seeing what was so special about the Lagoons. This is after all the "Cruisers Forum", not the sailboat forum, the trawler forum, or the catamaran forum.That's correct this is an open Forum the thread is in sub-headings 440 - Lagoon hence identifies the group

Second, I can't think of anyone on this thread that said anything negative about catamarans, Lagoon or otherwise. In all the time I've been on this forum I can't remember a time when there was a negative comment raised about catamarans. Not one. Mmmmm ok maybe you've not been active in a thread when it's come to the fore, possibly with you not owning a Cat you simply haven't noticed

Third, as for myself, I'd love to have owned a cat. However, my wife of 43 years is also an avid sailor and loves monohulls. So even though I tried, monohulls it was. Not that she disliked them, she simple preferred the sounds, motion and familiarity of the monohull.That's exact opposite for us i've built many round bilge ally and steel mono's then i built a Cat and my wife demanded it was Cat's from then on. There's a lot to be said about the feel of a mono when in the 'slot', the feedback is unmatched.

I understand the issues of dissimilar metals and that sometimes, on a boat, unusual space constraints require special considerations. That I clearly get. And if you look at the 'Brass' ball valve that Dirkdig posted Lagoon/Beneteau put the same valve on the engines 'hard connected' ie metal to metal!!!

However, your comment, "(the sewage holding tanks being the exception.) is that a 'bog standard Lagoon' has no seacocks!!!! I'll repeat HAS NO SEACOCKS." I'm having a little trouble with. I understand that a straight production Lagoon, for what ever reason, uses a combination thru-hull and ball valve. And that the waste system uses a seacock. Sorry, sadly the term 'Seacock' now means a skin fitting screwed to a ball valve, further comment below.

My questions are: Is there any reason for that combination being the sole option for a Lagoon? (metal and unique space issues aside) I noticed the pictures submitted by Dirkdig and they seem to suggest that a proper seacock with an elbow tailpiece would work just fine in those locations. Your comments. The only thru hulls on a 'bog standard' is the three or four waste tank outlets, the numbers vary as to what cabin layout you go for.

Also, is there a special reason why you would suggest that the waste system alone was a candidate for a proper thru-hull/seacock combination? Additionally, is it possible for someone buying a new Lagoon to special order (at a price)
the boat with US seacocks? No Lagoon will only fit options listed in their brochure, any deviation is done by contractors after handover, organised by the customer and payed for by the customer.

FYI - Sadly, the ABYC has chosen to, on it's own, redefine the term seacock to include a thru-hull and ball valve combination. However, when I refer to a seacock I'm talking about a valve (ball or cone) that has a bolted flange that attaches directly to the boat or backing plate and solid housing that accepts the thru-hull completely into the housing.We both have the same opinion regarding terminology, now the pic's Dirkdig posted are very typical of the fitment of thru-hulls to Lagoons BUT the picture will be of an 'extra' that's been optimised at order ie A generator, a watermaker, air-conditioning or salt water deck wash etc.
Remembering the engines feed water via internal galleries through the legs.

Cheers i hope this answers the points raised, also three of the units i pictured were for converting the sinks in the heads to free drain by gravity rather than the dumb draining to the shower pump.

As the project moves on i'll post progress pic's. As i pointed out this is to assist Lagoon owners to get rid of the rubbish valves that are in no way (in my opinion) correct.

The sewage valves are normally closed and appear to be of good (plastic) construction, these valves would suit a Marelon/Groco design unit for the compactness in a very tight area.

[Watercolor]

Lagoon4us - Thanks for the response. I have to ponder your responses. The changes that these standards organization have created are mystifying and conflicting. Definitely it has created some confusion, false assumptions and down right misinformation to boaters. For example, why would they (ISO, ABYC) use a, "dry as molded" parameter for seacocks, thru-hulls and ball valves that live in a water saturated environment and when different plastics react differently to water. Sadly, when asked neither ISO or ABYC have a clue. An interesting way to create a standard.

This is an interesting and critical topic and that I've been following for awhile. Just this last week I decided to write about it. In the process I will be contacting TRUDESIGN again regarding the EMS data and if you're interested I'll pass what ever I get on.

I appreciate your candor and input.

Fair winds

[s/v Jedi]

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

[micah719]

Sadly, when asked neither ISO or ABYC have a clue. An interesting way to create a standard.

Cynical spectators may suspect money has an interest in it.

[Lagoon4us]

That's all good, i'm most interested in your results.

Something i find quite strange on these tests is a standard should, as part of the prelim brief say "Once fitted in situ should be able to withstand a force of 'x' kg's" etc.

A bolted 'Seacock'/Valve should be bolted, a skin fitting if it has a ball valve fitted is NOT a 'Seacock' it's an 'assembly' and that assembly because it differs from the traditional Seacock needs to be supported not simply hang in the air.. It won't be long till you see Nylex hose between Skin fitting and Ball Valve...

Charter vessels i've built to the USL Code have all had sea-chests with flanged bolted ball valves on them for each take off with a larger ball valve bolted to a welded spigot (to the skin). At no time would we consider using a ball valve without mechanical support to the hull or B/head....

Sad how standards have been lowered.

Cheers.