Normal Thru-Hull aging?

[crayiii]

I'm attaching a couple photos on a Thru-Hull that I'm curious about. Unlike the other ones, this one has a bit of white chalky stuff on it. Is this an issue?

[a64pilot]

I don’t believe so, but many will tell you that a ball valve directly on a thru hull, especially with so many threads showing isn’t the best strength wise.

I changed my waste tank thru hull the other day that was 32 yrs old. The ball valve was so seized we had to cut it off and then cut the retaining nut off by cutting it in half.
But the condition of the thru hull was excellent and in fact it’s wall thickness was thicker than the new one I installed.

However your installation there is weak, be sure nothing can pull hard laterally or anything heavy fall against them.

I guess it couldn’t hurt to clean it up and check it’s color, look for pinkish, that’s a bad color.

[sailorchic34]

Hum, that white residue might be zinc oxide from the valve dezincing a bit. The weak point of any ball valve is where the valve stem connects to the ball. With that much corrosion on the body and handle, if it were me I'd replace it. Have you checked that the ball valve closes tight. I've replace it with a real sea cock. Or at least using the garco flange and ball valve

[HopCar]

That installation really scares me. I don’t like ball valves on through hulls and I really don’t like that much thread showing. My list of broken thru-hulls that we’re installed like that is up to three now. If you’re too cheap to buy a real flanged seacock at least cut that thru-hull down until there is only about half an inch of threads exposed. That still doesn’t address the problem of mismatched threads.

[crayiii]

The boat surveyor told me it's pretty normal for production boats. It's a 2 year old Lagoon cat.

Then he said "Personally I would recommend replacing all of the brass skin fittings and valves".

[Discovery 15797]

I agree with the surveyor, and I would replace the brass with bronze fittings.

Brass is notorious for dezincification which significantly decreases the lifespan and should never be used for thru-hull fittings...especially below the waterline.

Ball valves are not necessarily bad, and have been used on boats for eons, and are commonly found on virtually all production boats.

The biggest problem I see with this particular installation (other than the fact the thru-hulls are brass) is that there are no backing plates on the inside of the hull.

Also make sure all fittings match..there are 2 types of threads NPT and NPS. You want all NPS threaded components.

https://trip.ayy.fi/wordpress/wp-con...8/Seacocks.pdf

[a64pilot]

You never said anything about brass, yes if it’s brass. Then it needs to go.
Just me, but I’d rather use Groco’s flanged adapter than the old seacock, I think it’s a superior design in that you don’t put more holes in the boat, which becomes more important with newer, thinner hulls, and it gives you the ability to change the valve without replacing the whole thru hull etc.

To use the Groco flanged adapter, you replace the thru hull of course, but also bond a backing plate to the hull, then use the adapter and ball valve.
Studs are used that screw into the packing plate as opposed to drilling holes in the hull.
I’ve been told that bronze studs are hard to source, so just cut off the head of bronze bolts.

I’ve yet to do a full install of the flanged adapters myself, but when the need occurs, it’s my plan.
My thru hulls and ball valves are 32 yrs old, and based on cutting up what should have been the worst one, I don’t think they need replacing anytime soon

[Sailmonkey]

This is what a good 3 year old through hull valve looks like.




And this is what a good 43 year old through hull looks like.



Neither one has any white on it. I suspect that, as others have said, those valves are brass, not bronze, and the zinc is leeching out.

Replace.

[Cheechako]

It is a bit white. Hard to say but may be dezincing from a brass valve. I also dont like the very tall threaded thru hull. Installer was too lazy to cut it short. It just puts leverage on the threaded section which normally have very thin material at the thread root. Maybe on the order of 1/16" thick or less. Any corrosion and ...."snap" "gush" !

[crayiii]

I took a wire brush to it and it cleaned up. It's a thru hull for the generator that was just replaced under warrantee and it looks like salt water leaked from the hose. I sprayed it with corrosion x but plan on replacing it at haul out in 6 months.

[capt jgw]

If bet the through hull is NPS (straight thread) and the valve is NPT (tapered thread. Almost everything in a regular hardware store of NPT). They are incompatible. If you screw an NPT female onto an NPS male, as this appears to be, you'll only get one or two turns of engagement. One good bump and the valve will break off. And as days earlier they all need backing plates. Not to mention the brass. The whole setup is crap, but that's the way a lot of boatbuilders do it now. It all needs to go away.

[crayiii]

I'll be honest, it really pisses me off to think about how much I spent on this vessel just to find out that the (well known) builder placed my family and my property in jeopardy. I'm currently in the Caribbean and it's going to be a while until we can haul out. Also going to be awhile before I sleep well...

[a64pilot]

I believe the French built boats thru hulls and ball valves threads match, I think the thread mismatch is a US boat thing.
However brass should never be below the water line. I'm surprised insurance companies allow it. There apparently must not be many boats sunk due to it or surely they wouldn't ?

[a64pilot]

Originally Posted by crayiii

I'll be honest, it really pisses me off to think about how much I spent on this vessel just to find out that the (well known) builder placed my family and my property in jeopardy. I'm currently in the Caribbean and it's going to be a while until we can haul out. Also going to be awhile before I sleep well...

Two years old, I wouldn't worry too much.
I think the replacement interval is five years? There is a requirement of how long they have to last, I think that may be five years, and therefore whatever is used, must be good for that long.

I'm not sure how long they have to last but am pretty sure its well longer than two years.
If there had been many failures on young boat we would have heard about it, surely.
I'd still plan on replacing, but wouldn't lose sleep over it

[crayiii]

Our morning/night (we liveaboard) routine is to inspect the bilges, that's been slacking a bit recently but we'll pick it back up.