Brass tru-hulls

I was lead to a forum where the text below was posted. If against the rules of this forum, Carl please edit or delete. Found it very interesting info that I wanted to share:



"I'm deliberately making this post in a new thread as it potentially relates to any boat built to EU RCD standards, not just to boats physically built within the EU, or to one particular brand.

Another thread draws attention to the possibility of having poor quality seacocks and through-hulls fitted to Lagoon catamarans. However, it seems the problem could be much more widespread. Further reading took me to a website with an article entitled, The Wrong Seacocks Can Sink Your Boat. In case the article ever disappears from the other website I've copied and pasted it below:"

Quote:
Cruising Association Lecture Notes:
The Wrong Seacocks Can Sink Your Boat


Another great lecture at the Cruising Association earlier this week, this time on Surveying Yachts and Small Craft with Paul Stevens, yacht surveyor, lecturer and author. Paul currently teaches at the International Boat Building Training College in Lowestoft, UK.

Did we like him? Yup. He was passionate about his topic and it’s clear he knows his stuff. He cares about getting it right and keeping people alive on yachts that are safe.

The first half* of Paul’s lecture covered a serious issue he has helped to build awareness for recently: the use of brass skin fittings below the waterline… in salt water-sailed yachts!

What’s wrong with that? Apparently everything.


So What’s Wrong With Brass Fittings?
Brass seacocks in saltwater can corrode to failure in 5 years… or less!

Dezincification
Brass fittings in fresh water – okay. But in salt water, brass (an alloy of copper and zinc) corrodes to failure. It's called dezincification. If there is any current in the water (as often happens in a marina) this can happen in less than a year.

What drives this?
Well, it costs about a quarter of the price to make a fitting out of brass...

Is this new knowledge?
Nope. Apparently the downside of using brass in this way has been known for about 90 years or more.

Why did this happen?
The new (since 1998) European Community's Recreational Craft Directive (RCD) ISO Standard 9093-1 was rewritten to require only that fittings should be corrosion resistant for 5 years. (Though who knows why they were rewritten this way??…)

Huh? Not required to last the life of the boat, you say?
Nope. Not under the current EU regs.

And if they corrode through and fail beneath the waterline my whole boat will sink??
Uh-huh. Pretty fast too.


Is there a disaster waiting to happen under my waterline?
Yacht owners need to prove to themselves that their fittings are NOT brass.

There is currently no requirement in the EU to mark on packaging what components are made of. And the packaging of valves with and without brass are nearly identical. Even many chandleries are unaware of the difference between them due to this lack of clarity. Big problem.


How to check
Got written documentation of what your fittings are made of? Old packages? Documentation from the manufacturer of your boat? Can you write the manufacturer and get this in writing? If you are buying a new boat, the builder should definitely be willing to write this down…

You can also hammer-tap test every fitting that pierces the hull below the waterline. Even if the fittings were all put in at the same time and some of those other fittings have tested okay. Fittings may have been subsequently replaced with brass. Or some brass fittings may have gotten mixed in when the boat was first built due the unclear and very similar packaging.

Brass corrosion shows as a grey pinkish putty colour. It showed up as splodges on the outside of valves and especially in the threads of valves that Paul had to show us. Does the fitting collapse when you hammer-tap it (not a guaranteed test)or break off? Not a good sign.

If you can’t prove to yourself that all your fittings are not brass, then be safe. Replace them all.

Prevention is far cheaper than calamity.


The Right Stuff: Bronze and DZR
We should be using bronze! Or products that are clearly labelled/confirmed as dezincified resistant brass (DZR). Plastic is a possible alternative, but shouldn’t be installed around heat sources – say in or near the engine box.


How to be sure you’re getting bronze or DZR
If you don’t have documented proof that it’s not brass – better to be safe and replace them all.

How do you ensure this? Here are some ways:

If the package states clearly that the product is bronze or DZR, then okay. If it does not mention what material it’s made of… then it’s brass.
If the valve shows the ‘CR’ symbol on it when you turn it over, then it’s DZR. That’s good. But you can’t necessarily see this when it’s in the package.
Another clue – bronze fittings cost 3 to 4 times more than brass ones.
Blake seacocks now use DZR only.
ISIS make a range of DZR ball valves.
New Zealand make the True Plastic Range by Lee Sanitation. Also okay.
ASAP Supplies will supply a list of what things they sell are made of.

Here’s a link to Paul’s site and articles on seacock safety and technical metals info. Here’s info on Essential Seacock Checks.

After Paul’s talk it looked like the vast majority of attendees would be down at their boat this weekend, checking for documentation and hammer-tap testing away to ensure the integrity of their fittings and the safety of their yachts.


Do you know what your seacocks are made of?

The Essential seacock checks article is from Yachting Monthly (a UK sailing magazine) and is copied below for reference:


Quote:

Essential seacock checks

Tue, 31 May 2011 | Comment on this article

How to check your boat for safe seacocks



Yachting Monthly is campaigning for tougher rules on seacocks, which currently only have to last five years, according to a European directive.

Our whistleblower surveyor Paul Stevens, 58, a founding member of British Marine Surveyors Europe, blew the lid on the directive after finding a worrying number of yachts fitted with brass seacocks designed for domestic plumbing systems, instead of the longer-lasting bronze or marine brass.

The European Community's Recreational Craft Directive (RCD) of 1988 introduced an ISO standard for through-hull fittings stating they should be corrosion-resistant for a service life of just five years.

The Cruising Association has since backed our campaign and we have been contacted by yacht owners across the world for advice on how to check their boat's seacocks.

Here is surveyor Paul Stevens' advice:

What can be done to minimise the risk?

1. If your boat is still ashore scrape the external flanges of the through hull fittings clean and examine them for pink spots and pitting (see Elan pic from first article). If this is found they are almost certainly ordinary brass and the only advice must be to replace them.
Examine all valves for numbers with CW or CZ prefixes, these are the only one that appertain to the material, and for the CR corrosion resistant logo found on genuine DZR valves. CW617N is for ordinary brass, whilst CW602N indicates DZR brass. In my experience genuine DZR valves are finished in their natural gold colour and not plated to give a silver appearance.
Lightly hit the body of the valves with a screwdriver and hammer. it hHMove the hoses back and forth to test the strength of the tails.

2. Ask the builder the following questions:

Can you please confirm that ALL the components used in the seacock assemblies are in compliance with ISO 9093-1 in terms of their corrosion resistance.

Can you please confirm the European CW designation for the materials used in ALL the components in the seacock assemblies? (Once this number is known the exact composition of the alloy and thus the component's suitability for saltwater use can be established).

I cannot emphasise enough the need to establish the material used for all components, ie the through hull, the valve, any 90 degree bends etc plus the tailpipe for the hose.

3. Disconnect all through hull fittings from anodes. There is a general consensus that a conventional bonding system may actually encourage corrosion of the fittings.
Experience shows that the most vulnerable fitting is the engine cooling water inlet and isolating this from the engine after any bonding wires have been removed is not as straightforward as it may seem. This is because most hoses used in this application are spiral wound with stainless steel wire to prevent them collapsing under suction, and this wire often provides continuity between the engine and its intake valve assembly. Test this with a simple circuit tester.

4. Fit a galvanic isolator, this should mop up any stray currents and minimise the risk of electrolytic action.

See the August issue of Yachting Monthly for the latest on our campaign, as well as an real-life story from a reader who saved his boat after devising an unusual method of stopping his yacht's broken seacock at sea.