Steel boat : stanchions all corroding, is it galvanic?

[jorxster]

Hi all, I've just bought my first yacht, a corten steel 1987 Feltz Skorpion.

One thing I've been told is all the stanchions are aluminum. They seem to be fitting into (possibly stainless?) steel fittings which are then welded to the bulwarks (a tube shape).

Almost every stanchion, shows signs of corrosion and rusting below. Is this galvanic, because of the aluminum stanchions? Or is it simply unavoidable due to the topography/shape of the metal?

I have a 3d printer, I've been thinking to create little cup shapes to encapsulate the aluminum ends inside the steel. But not sure if it'll make a difference.

Lastly, in one photo, there's a tiny hole into the bulwarks bar interior, which is hollow. I'm not sure if simply dealing with the rust, epoxy filling the hole, and filling it in is a good idea, or if I need to cut out a larger section to examine the inside + weld?
cheers,
Jordan

[tkeithlu]

I'm going to have to place a bet rather than answer with assurance. The holders and the rail appear to be stainless steel. My bet is that salt water has accummulated in those holders and is causing the steel of the hull itself to corrode. That bet is because the corrosion is iron, not aluminum, and stainless steel doesn't rust quite that way when it does at all. Putting a stop to it will involve first getting all corrosion out of there and then sealing it up to keep water out. As it's designed, water runs down the stanchion into the holder, and.....rusts.

[hpeer]

Aluminum stansions would not be a great idea, they would corrode to protect the steel. My guess is they are quite weak.

I frequently have corrosion where mild steel and stainless come into close proximity, say a bolted connection or just close. If I weld the connection the problem is far less.

BUT you will surely get a wide range of opinions here on these subjects. I am not an doert but have 2 steel boats.

Get this book and read through it. I would not hang on every word but jt is a great starting place.

https://books.google.com/books/about...d=peIEMVOvOIQC

[boatpoker]

Those certainly look like aluminum stanchions to me. Any contact with steel or stainless will corrode the aluminum. The points of contact between these two metals will most likely also cause crevice corrosion in the stainless steel.

Unless those stainless pipes have holes drilled for drainage, crevice corrosion is also likely to form due to stagnant water sitting in the pipe. SS requires oxygen to maintain the passive coating (that makes it stainless). Stagnant water is by definition de-oxygenated.

My two cents as a retired Certified Marine Corrosion tech.

[Briis]

Also from a steel boat owner: as said above I agree - definitely a galvanic corrosion, since visually it's very obvioys - the shiny pipe is a stainless steel that is welded onto mild steel hull, to my amazement. The builders obviously know very little about the galvanic table I reckon(?) This is very bad combo.

Steel boats should look like steel boats. Do not try to make them plastic- or stainless steel shiny queens look.

On a steel boat you ought to keep the connected materials the same type. Mild steel is an all out excellent enduring material, if you paint it and keep it at bay seasonally, it will last decades, a hundred-year-old steel boat is not so uncommon here in Europe with that simple care. But if you introduce it to "aliens" (materials in higher galvanic order such as brass, stainless etc) it will reject it and cry, i.e. corrosion.

I'd recommend cut out the stainless steel supporting pipes. Weld the supporting rods directly to hull (provided they are mild steel and weld with mild steel welding accordingly - the same material principle). Then clean the surface, a bit surface sand for grip, prime and paint it couple of times - and you're done for years till just minor seasonal maintenance is required.

YMMV of course.

[skipperpete]

The welds on the stainless steel look appalling, if that stainless toe rail is actually welded to the deck it will be a constant source of corrosion if it has the same poor welding as at the stanchion bases. If it’s not welded to the deck, or just stitch welded it will still be difficult to maintain. Definitely weld up that hole in the deck chine, hopefully it’s heavy wall tube. The upside with steel hulled yachts is that problem areas can simply be cut out and new plating installed by a decent steel fabricator/welder. Feltz builds pretty good hulls but I guess that the toerail was a later addition.

[hpeer]

As I said you will get a wide range of opinions.

I have mild steel and stainless welded together on both boats, I see no problem. They even make special rods for stick welding the two. Where I do have problems is with bolted connections. Like stainless hinges into mild steel. Not always, but often.

I have a stainless bar welded to the top of my toe rail, then some teak. Somewhat similar to your set up. I have no problem with the welded connection. 1987 built hull.

I would get rid of the aluminum stanchions. Go for stainless stanchions. Your life lines go through there, you don’t want them to break. Your life will depend upon them, seriously.

I suggest you drill a little hole in the stainless tubing right at the bottom to let the sockets drain.

You need to learn to weld at least a little. It is not hard. You can purchase a small inverter stick welder for about $200. Then get an auto darkening helmet and some gloves. And some standard rods, the small type for the little welder. The store can help you. Then get some scrap steel of various sizes and shapes and start sticking stuff together. Drill some holes and fill them. Watch some youtubes. You will find rust is a bitch.

When you have a little experience then use a drill with a wire brush to clean up the hole and then weld it shut. It will get a rough and lumpy. Use an angle grinder to smooth out the lumps. Fill in the voids. Then paint.

You will have reason to do this here and there as long as you have the boat. Needing to hire a welder for every little spot will break your budget and spirit.

There is nothing here you can not deal with. Just apply some gumption and forgiveness. Know you will make mistakes and that is OK. It is a damn site cheaper than a college course and you will learn more.

REMEMBER:
Perfect is the enemy of Good Enough (and a happy life).

Welcome aboard.

[jorxster]

Thanks for all the replies! appreciate it.

Yeah perfection is the enemy of good enough... and I'm a perfectionist, so that doesn't help!

[MicHughV]

As an ex-steel boat owner...you are going to be chasing rust for as long as you own the boat....it's just part of owning a steel boat......it is mostly a "nuisance" issue, as you'll get rust "stains" here and there.

What you need in your arsenal of " repair" stuff is some " ospho" or similar product, which is a rust neutralizer, a dremel tool, wire brush, some zinc paint and some one-part polyurethane paint to match the color of your hull, deck, etc.

As stated above, you can buy a "mini" welder for around $150-200 on Amazon, which will run on both 110 and 220v, learn to use it.

[hpeer]

^ 1+

Correction - you WERE a Perfectionist, now you are a sailor. LOL

Perfectionist polish their boats at the dock, sailors sail.

[MicHughV]

The real heartache with owning a steel boat is coming into port after spending weeks at sea. Endless salt spray over the bow will find the tiniest corner to grow and fester and a nice rust bloom will result somewhere....usually the stanchion or stanchion base, anchor rollers, bow pulpit, etc.

There is not much you can do to tackle rust or rust stains at sea, except look at it.....grin and bear it...

[jorxster]

Oh just thought I'd post to leave a summary on this issue.

I finally figured out all the work that it would take, to replace the stanchions with steel and get them re-rigged with steel lifelines, would end up costing me almost 4k here in NZ.

So I decided, rather I'll pull one at a time and try to electrically insulate the aluminum by painting the bottoms where they come into contact with the steel.

[boatpoker]

Originally Posted by jorxster

Oh just thought I'd post to leave a summary on this issue.

I finally figured out all the work that it would take, to replace the stanchions with steel and get them re-rigged with steel lifelines, would end up costing me almost 4k here in NZ.

So I decided, rather I'll pull one at a time and try to electrically insulate the aluminum by painting the bottoms where they come into contact with the steel.

I believe the aluminum primer paint is conductive. even if it isn't, one scratch in the finish coat and you are back to square one. That first scratch will likely be caused by the securing fastener.

[Ballsnall]

Originally Posted by jorxster

to replace the stanchions with steel and get them re-rigged with steel lifelines, would end up costing me almost 4k here in NZ.

You now own a steel boat, you need to learn how to diy. $4k to replace the staunchions sounds like $300 in materials and $3,700 in labour. The ally staunchions are dangerous and will break putting someone overboard, buy some stainless tube and replace them.

The rust in the first photo is due to crappy paint preparation not galvanic corrosion, you'll learn all about that with a steelie. The galvanic corrosion is on the aluminium stanchion.
Stainless steel welded to mild steel on boats is generally not an issue and very commonly done

[ChrisJHC]

Originally Posted by boatpoker

I believe the aluminum primer paint is conductive. even if it isn't, one scratch in the finish coat and you are back to square one. That first scratch will likely be caused by the securing fastener.

I think the original idea of printing non-conducting “cups” for the stanchions to sit in would also work as a work-around.
Then look at a permanent fix down the line.