Another Seacock Question - replacing through hulls and ball valves with Blakes?

[Tranona]

Of course it does, it was drawn up by manufacturers to give a minimum standard for each category, no doubt based on cost effectiveness. Items have to last only for 5 years but they don't remind owners to check them after that period.

That is simply not true. The standard was drawn up by a working party of the EBA with significant input from the UK. As noted several times in previous discussions on this subject the 5 year rule was nothing to do with manufacturers and they did not make any changes to their practice as the brass valves they had been using for years far exceeded this requirement. I suspect if the period had been set to double rgar brass would still meet it.

 

[GrahamM376]

That is simply not true. The standard was drawn up by a working party of the EBA with significant input from the UK. As noted several times in previous discussions on this subject the 5 year rule was nothing to do with manufacturers and they did not make any changes to their practice as the brass valves they had been using for years far exceeded this requirement. I suspect if the period had been set to double rgar brass would still meet it.

The EBA is just an Association and the RCD was to give manufacturers a level ball park with minimum standards of construction and stability. Many boats are built to a price which no doubt entails the minimum allowable to meet a particular category and, as components only have to last a minimum of 5 years why would they fit more expensive ones? I agree that most brass will outlast that period but others will fizz away quicker than dzr.

 

[Tranona]

The EBA is just an Association and the RCD was to give manufacturers a level ball park with minimum standards of construction and stability. Many boats are built to a price which no doubt entails the minimum allowable to meet a particular category and, as components only have to last a minimum of 5 years why would they fit more expensive ones? I agree that most brass will outlast that period but others will fizz away quicker than dzr.

What are these other types that might fizz away? Do you have examples?

The point about the RCD is that it was NOT written by the manufacturers but was an EU sponsored standard drawn up by independent experts. The notion that manufacturers wrote that requirement so that they could fit inferior products is just not so. No changes resulted from the requirement - they just carried on using the same components. Would really love to see reliable evidence of seacocks fizzing away on their own - that is without there being faulty electrics or inappropriate bonding.

This is not to say that dezincification does not happen with some brass valves - just that there is little concrete evidence that it results in sinking of vessels.

 

[GrahamM376]

What are these other types that might fizz away? Do you have examples?

I was referring to brass. Many stand the test of time but others will degrade quickly in some situations, mostly marinas with stray currents. My own choice on replacement of underwater fittings was/is TruDesign composite. People seem to have a fixation on seacocks failing whereas in most cases I have first hand knowledge of, it's the hose tails and through hull fittings which crumble away first.

 

[Zing]

You do not seem to have a clue what you are talking about. "sTrength" is largely irrelevant in this application as seacocks are under no stress being firmly clamped to the hull. Indeed even a completely dezincified brass body (rare) will maintain its integrity unless it is hit or wrenched..

This is wrong thinking and the wrong attitude to safety and the wrong appreciation of what I am saying. Strength is highly relevant. So much of what we do in improving safety is in preparing for uncommon events and here it is no different. You are implying that being hit is not going to happen, well it does happen. Objects do break loose and do fly around the bilge and heavy objects require enormous strength from the to withstand their deceleration force. That 300lb crew member who trips up and falls against the valve whilst rummaging in the bilge will need a tough seacock to withstand the force. You may also suffer a grounding and it doesn't take much to imagine the outcome. I would rather have some tough bronze rub against the rock than a toy plastic through hull. These are the sort of tests that will show a fail for plastic and a pass for bronze.

 

[Zing]

...Sometimes you just have to put your faith in the manufacturer. ..

Yes, we do it all the time, but often because we don't have a lot of choice and because the probability of his failure is astonishingly small. I'd rather not rely on faith if I didn't have to and here there is no need to as there are safer, slightly costlier alternatives. The only advantage from doing so might be to save a little money and if you go for plastic, you are not even doing that, so taking a risk for no gain. When I replace I will definitely find a bronze one.

 

[NormanS]

Yes, we do it all the time, but often because we don't have a lot of choice and because the probability of his failure is astonishingly small. I'd rather not rely on faith if I didn't have to and here there is no need to as there are safer, slightly costlier alternatives. The only advantage from doing so might be to save a little money and if you go for plastic, you are not even doing that, so taking a risk for no gain. When I replace I will definitely find a bronze one.

Just as a matter of interest, what material is your boat made of?

 

[GrahamM376]

...............The only advantage from doing so might be to save a little money and if you go for plastic, you are not even doing that, so taking a risk for no gain. When I replace I will definitely find a bronze one.

It seems you most likely haven't watched the testing videos or read the fitting instructions for TruDesign which advises using epoxy for fixing through hulls so they become integral with and as strong as a grp hull. You keep saying "plastic" which generally refers to the type fitted high above the water line for bilge or wash basin outlets and I think everyone would agree those are not suitable under water. Composite ones however have been in use for years on commercial as well as pleasure vessels and I've yet to hear of a failure - do you know of any?

 

[vyv_cox]

Yes, we do it all the time, but often because we don't have a lot of choice and because the probability of his failure is astonishingly small. I'd rather not rely on faith if I didn't have to and here there is no need to as there are safer, slightly costlier alternatives. The only advantage from doing so might be to save a little money and if you go for plastic, you are not even doing that, so taking a risk for no gain. When I replace I will definitely find a bronze one.

Having been employed in the metal producing industry I would be astonished if the base metals were not produced to specification. Your faith in bronze is admirable but you have to put just as much faith in the composition of that as you would any other metal. And even if every component was exactly to specification there is no guarantee that it all fits together correctly, for example is the ball plating likely to last ten years or three weeks? As I said before, you put your faith in suppliers and manufacturers with a proven track record.

 

[macd]

Sorry, plastic is weak, as in wet lettuce weak compared to a good bronze.

I'd hate to try one of your salads.
You ought to try attacking a cheap polycarbonate motorcycle crash helmet with a 4lb hammer. It took four of us, all hefty blokes, fully half an hour of hitting it as hard as we could before it split.

 

[Tranona]

This is wrong thinking and the wrong attitude to safety and the wrong appreciation of what I am saying. Strength is highly relevant. So much of what we do in improving safety is in preparing for uncommon events and here it is no different. You are implying that being hit is not going to happen, well it does happen. Objects do break loose and do fly around the bilge and heavy objects require enormous strength from the to withstand their deceleration force. That 300lb crew member who trips up and falls against the valve whilst rummaging in the bilge will need a tough seacock to withstand the force. You may also suffer a grounding and it doesn't take much to imagine the outcome. I would rather have some tough bronze rub against the rock than a toy plastic through hull. These are the sort of tests that will show a fail for plastic and a pass for bronze.

If you are basing your argument on seacocks being hit you are not following your own advice. They should be placed where there is no chance of them being hit. Just bad design if they are vulnerable. No chance on my boat pf any of the seacocks being hit.

still stand by my statement that strength of the material of the body is of little importance - although all materials, brass, DZR, bronze and composite are more than strong enough - so no argument. As I said nearly all metal ball valves suffer from the same weakness in the spindle/ball assembly, although some of the newer ones such as Vyv mentioned do have DZR balls.

Why do you insist on using such a silly term as "toy plastic through hulls" when the two main types of composite ball valves made by Forespar and Tru Design are nothing like that. You should really find out about the material they are made of before making such silly statements.

 

[Tammany]

In the 60's they said plastic boats would never catch on as well.

 

[Zing]

I'd hate to try one of your salads.
You ought to try attacking a cheap polycarbonate motorcycle crash helmet with a 4lb hammer. It took four of us, all hefty blokes, fully half an hour of hitting it as hard as we could before it split.

Horses for courses. That's an impressive result and polycarbonate is a tough material and formed in a strong shape and great for crash helmets as it is light, but strong and tough enough for the job. If you are to withstand bullets then steel will work, whereas polycarb will not. Still, I think I would pick Kevlar in a war zone. I've got nothing against plastic in the right place. Polypropylene makes a better choice than steel in watering cans too for what it is worth.

 

[Zing]

In the 60's they said plastic boats would never catch on as well.

There are actually no plastic boats bigger than dinghies. Maybe the older ones were over half plastic, but the newer, vacuum bagged boats are mainly glass and in terms of strength all are more accurately to be considered glass boats as 90% or so of strength comes from glass. The resin just holds the glass together and waterproofs the structure.

 

[Tammany]

That's just being picky lol. Tru design now do a collar that fits round the bottom of the seacock that basically turns it into a big solid block of plastic and rated for 500lbs of side pressure with this fitted just in case someone or something is pushing on it. I used this too. I only have one seacock that feeds the engine so fitted this as a precaution but it's in a place that's protected anyways.

 

[Kukri]

Just to stir the pot, I actually do know someone whose boat sank on her mooring, in darkest Pin Mill, not so long ago, due to the failure of a closed seacock.

 

[NormanS]

Just to stir the pot, I actually do know someone whose boat sank on her mooring, in darkest Pin Mill, not so long ago, due to the failure of a closed seacock.

You can't just leave us there. What kind was it? What happened? What caused the failure?

 

[macd]

There are actually no plastic boats bigger than dinghies. Maybe the older ones were over half plastic, but the newer, vacuum bagged boats are mainly glass and in terms of strength all are more accurately to be considered glass boats as 90% or so of strength comes from glass. The resin just holds the glass together and waterproofs the structure.

So glass reinforced composites are OK?
That'd be Trudesign's description of their material, in a nutshell.

 

[Kukri]

You can't just leave us there. What kind was it? What happened? What caused the failure?

I quote Pete himself, ("Transcur") on the East Coast Forum, right here:

quote

Transcur was floating normally on Friday eve at 8:00. At the bottom of the Orwell at 1:00.

The engine intake skin fitting failed catastrophically. We had heard that there were some boats making a large wash in the Pin Mill area that afternoon evening. Likely that the Flare box, quite heavy, slipped and hit the strainer causing an unknown seriously corroded skin fitting to fail.

Very depressing, worst nightmare. We were to be crossing to Holland for three weeks on Saturday. Could have been interesting in the middle of the North Sea!!

The mess down below has to be seen to be believed.

Should be up and running again soon.

I must add a huge thanks to the 18/20 people who helped on Monday eve when she was brought to Kings yard stripping her of anything that moved, washing the removed contents.

And to the other help received over the past few days.

I suspect there will be a lot of people checking skinfittings this winter. Highly reccomended.

Recovered by Mistley Marine and a team of 5 divers.

Pete

Unquote

Pete is frighteningly competent and indeed she was up and running again soon after...

I'm just replacing "Sunbeam"'s equally nasty engine intake now. "Mirelle" when I bought her had an exhaust outlet on the waterline, there from new in 1937, which combined a steel elbow with brass gate valve and a bronze skin fitting. One day a surveyor hit it with a hammer and it fell apart. It literally crumbled into flakes of rust and cracked copper sponge (dezincified brass)

 

[NormanS]

Ah, so it wasn't the seacock at all. It was the skin fitting, hit by a loose object. Commiserations though.