Seacock: Bronze or Marelon

[stevec195]

You may also consider using a metal through hull and valve without bonding it to the grounding plate. Obviously there will be some normal stray current that will induce corrosion-but at a rate that will exceed the owners lifetime. I too have read and heard of several boats sinking due to the through hulls being blown out by lightning, and although there are no certainties with how lightning moves, not having your through hulls bonded goes a long way to solving this problem.


Sent from my iPad using Cruisers Sailing Forum

[contrail]

The other one they market to boat builders. I couldn't find it on their website but it has a round base and seems much better made. Even though Forespar doesn't try to sell this to end users, any Forespar dealer can order one for you.

Look for Series 93 in the OEM part of the Forespar website. They are there and they are excellent. Fat handle that doesn't break, too.

[CarinaPDX]

I am a little dubious about the premise of the OP that good bronze valves are not available in Greece. High quality plated bronze valves are manufactured in Italy and are widely available in the EU. I replaced all of my seacocks in Turkey with them 10 years ago, and my only complaint is that the handles are not stainless. Other than for metal hulls I feel more comfortable with bronze than plastic, even quality nylon reinforced plastic, for the long haul. Plastic does age...

Greg

[Brigadoon]

Had bad corrosion on the ball (bronze with chrome plate) with bronze seacocks after only about 5 years in the water. Corrosion may have been partly due to stray currents in the water at the dock (Chesapeake area). Chrome plate was eaten off as seen in picture. Relative to the chrome plated balls, stainless balls are probably much better, but are also much more expensive (for no apparent reason). Have replaced the corroded thru-hulls with Marelon.

[Cheechako]

Originally Posted by Brigadoon

Had bad corrosion on the ball (bronze with chrome plate) with bronze seacocks after only about 5 years in the water. Corrosion may have been partly due to stray currents in the water at the dock (Chesapeake area). Chrome plate was eaten off as seen in picture. Relative to the chrome plated balls, stainless balls are probably much better, but are also much more expensive (for no apparent reason). Have replaced the corroded thru-hulls with Marelon.

Yeah, although Ball valve types have been accepted in recent years, they are not infallible and nothing near as good as tapered bronze proper seacocks. My guess is SS would corrode worse having wet trapped oxygen depleted areas. SS ball valves are made for industrial use. Not cheap.

[crazyoldboatguy]

There have been other discussions on CF about this issue. It is where I learned about these fittings:

Marine Products | TRUDESIGN

Available many places - maybe even in Greece

P.S. Kallitsis Hose | TRUDESIGN

[HopCar]

The Trudesign that Crazy posted is an interesting system. Their valves have straight threads so they will engage with the thru-hull properly and their collar adds extra strength to the thru-hull. Be sure to buy one of their straight thread tailpieces to go with it. It's not good to screw tapered threads into straight threads, especially in plastic.

Raritan is the US distributor for Trudesign.

[sanibel sailor]

Be aware that the ones they sell as OEM have a proprietary thread pitch, not pipe thread compatible. Nothing will work except what they supply. Not sold in stores. Cross threading can be bad for your launch timing. Don't ask, but next time I am going to figure out how to hold the valve and thread in the thru-hull part both myself at the same time.

[captmikecoin]

Originally Posted by CarinaPDX

I am a little dubious about the premise of the OP that good bronze valves are not available in Greece. High quality plated bronze valves are manufactured in Italy and are widely available in the EU. I replaced all of my seacocks in Turkey with them 10 years ago, and my only complaint is that the handles are not stainless. Other than for metal hulls I feel more comfortable with bronze than plastic, even quality nylon reinforced plastic, for the long haul. Plastic does age...

Greg

If you have any references then please let me have them. The problem here in Greece is twofold. Firstly vendors will try to sell you anything they have in stock whether it's right or not and will describe it any way they think you want to hear. Secondly all yellow metal is called bronze and most vendors don't know the difference between brass and bronze suitable for seawater use. If you reject what they offer they are not prepared to look further as they take your rejection as an insult.

It's very difficult trying to get good quality components here in Greece and the yard mechanic has never heard of bronze seacocks being available here.

I've ordered from the US for now but will need more next year so any info on local availability would be useful.

Mike

[NathAnodyne]

Originally Posted by Cheechako

Bronze. Never Marelon for me. Been there, done that.

But why?

[sanibel sailor]

Despite all the tech and hype, it is still plastic and breaks much more easily than metal.

[crazyoldboatguy]

Originally Posted by sanibel sailor

Despite all the tech and hype, it is still plastic and breaks much more easily than metal.

I am using Tru Design reinforced fiberglass fittings. ABYC approved for use below the waterline. My depth transducer doesn’t come with that - it’s 316 SS.

[Cheechako]

Originally Posted by NathAnodyne

But why?

Handles broke off, seacocks wont turn. My guess is the plastic material is not stable enough to stay perfectly round on the mating parts? So they turn hard. Also, one little area of the shaft the handle turns is tiny.
People say "oh you have to cycle them regularly" . No I don't. The Japanese call it "Poka Yoke": making things so they work regardless of what idiot is using it!

Go to West marine, pickup a 1.5 or large one like that. Try to turn it. Brand new they are very hard to turn.

The basic material is killer tough. it's the details they seem to get wrong. The "weakest link in a chain" etc. I think if they cared a major redesign with that material would be killer.

[daletournier]

Originally Posted by Cheechako

Handles broke off, seacocks wont turn. My guess is the plastic material is not stable enough to stay perfectly round on the mating parts? So they turn hard. Also, one little area of the shaft the handle turns is tiny.
People say "oh you have to cycle them regularly" . No I don't. The Japanese call it "Poka Yoke": making things so they work regardless of what idiot is using it!

Go to West marine, pickup a 1.5 or large one like that. Try to turn it. Brand new they are very hard to turn.

The basic material is killer tough. it's the details they seem to get wrong. The "weakest link in a chain" etc. I think if they cared a major redesign with that material would be killer.

Mine are 18 years old and turn fine.

[MicHughV]

I had bronze thru-hulls on a previous boat. Boat was about 15 years old. Every one of them leaked.
That tapered plug inside the valve body had pitted....electrolysis the likely culprit. ???.
I'm not sure...I had two large bronze grounding plates on the hull for a ham/ssb ground and I never could visibly tell whether or not either one of them had deteriorated.

In addition, whenever I parked the boat, be it at anchor or at a dock, I would throw a sacrificial zinc fish" over the side which was tied into the boat's grounding system. The wear on this sacrificial " fish" was noticeable.
There could have been stray voltage from other boats or even the dock power system.
But even closing the bonze valve, water would work it's way around the tapered plug.

At a haul-out I pulled each tapered plug and spent many hours trying to sand those tapered plugs smooth. When I re-inserted the plugs I made sure to slather them with a good quality waterproof grease and gave each nut an extra few tightening increments.

It was all in vain, the thru-hulls leaked as before. Off course, I could not effectively clean the valve body itself, though I tried, and likely the valve body had pitted as well as the tapered plug.

The whole thing was an exercise in futility and at a subsequent haulout, at great expense and effort I removed all the bronze fittings and replaced them with marelon, a plastic thru-hull.

The leaking stopped ! Off course, I could have replaced the old bronze valves with new bronze valves, but decided the plastic would likely give me better protection, and yes, it was the cheaper option.

Interestingly, all the bronze valves were tied into a grounding system, which consisted of a grounding wire tied into one of the bronze thru-hull fittings.
Whether this was part of the problem, I cannot say, but whatever was eating one thru-hull was also eating all the others.

Modern plastics have come a long way and I would not hesitate to recommend the marelon variety of thru'hulls. Those things are built bulletproof imo.

Subsequent to their installation, I never had not had a single problem with them.

Off course, to each his own. One can read any number of " opinions" on this subject and this is simply my opinion.