What the hell is this!?! Rust / Corrosion Question

[eugenesdream24]

My Irwin 28 is a centerboard model. I was just cleaning up under the floor panels and cabin storage areas because I am beginning to paint and "pretty up" some of the unsightly rough fiberglass down below. Sure enough crawling around these areas for the first time I came across a terrifying discovery.

I started inspecting my centerboard SS cable which appears to be healthy enough (my rigging guy just gave it a proper safety look over) but I am finding a lot of corrosion and big chunks of rust in the well under the centerboard seacock which he told me just to clean up and remove. It is definitely old (down there hasnt been cleaned up in decades), but I am very concerned. I have a pretty big access point in my port side storage down near the centerboard cable where I found a HUGE piece that is a good 4-5" wide and 7-8" long.

The question is, where did it come from, how did it get there, and is this level of corrosion a really bad sign? I have read about corrosion of keels, cast iron or other metal hardware, but nothing like this. As far as I know my keel is lead but I cannot get into that area and this definitely did not come from that. These chunks are sitting in the fiberglass well below the centerboard cable and updated seacock, and the big chunk was just sitting in a storage area I never used. I'm shocked I never noticed it before until now. It was very well hidden from view but now that I found it I am very concerned.

The boat hull and body is absolutely clean and practically brand new on every other level. So I am flabbergasted more then anything by this odd discovery. Any thoughts or comments are appreciated.

 

[CloudDiver]

I can't tell what the hell that is either... I'd need more details on how you boat is designed/constructed as I'm not familiar with that model. The pic just looks like a slab of cast iron that was just sitting in the bilge, maybe for additional ballast? I'm also not sure what you mean by "As far as I know my hull is filled with lead".

 

[eugenesdream24]

I'm also not sure what you mean by "As far as I know my hull is filled with lead".

Lead keel is what I meant, my apologies for the bad communication on that. But obviously this is cast iron or something similar as you noted. It was not serving as any kind of ballast since it was loose and only weighs a few pounds anyway. No idea what it is either. My friend who is an older sailor with much more experience then me said he has seen worse, its just old boat stuff but it did not make me feel better.

 

[Kermit]

Thow it overboard. See how big a splash it makes. Post a video and you'll get lots of answers as to what it is (was) and what you should have done with it instead. The deeper the water the more valuable it will become.

 

[kito]

I wouldn't worry about it. Whatever it is it must not be important since it looks like it was laying loose and corroded for decades. What was above this piece? Just wondering if it fell off something.

 

[eugenesdream24]

I wouldn't worry about it. Whatever it is it must not be important since it looks like it was laying loose and corroded for decades. What was above this piece? Just wondering if it fell off something.

I thought of that but literally above it is the underneath of the cabin seats which is all fiberglass, below it was just fiberglass too and it was just sitting there. So the mystery continues but I have removed it and all of it's smaller crumbs. Now comes the ShopVac, quick scrubbing, and fresh paint. Like it never happened.

 

[woodster]

that thing looks like a brownie gone bad

 

[kloudie1]

To further obfuscate the issue, I am pretty sure that is a piece of plate carbon steel and not cast iron. The uniform layers of corrosion are indicators of rolled plate. My guess is someone may have been using it as a pad or an anvil or something??

 

[centerline]

its definitely not cast iron... cast iron doesnt flake, it will be mild steel.

it could be that some previous owner may have raced the boat and thought more ballast might help them out, so they snuck in some extra ballast...

OR.. at some point the boat may have had a bit of a list that aggravated someones sense of aesthetics, and that was their way of trimming the boat..

there are better methods for both...

 

[Benny17441]

Whatever it was, it is now trash. Throw it away and don't look back.

 

[shemandr]

I think Centerline has it: Added ballast. Can you contact the PO?

 

[CloudDiver]

Cast iron most certainly does flake because there is more than one kind of cast iron (grey, white, ductile, etc.). The type used to make pots and pans is much stronger than they the type typically used to cast keels and such, it all depends on things such as carbon content. I haven't seen nearly the number of cast keels eroded away as I have seen engine blocks and trans cases, but yes they most certainly do flake. The way that piece pictured is separating like soggy cardboard leads me to believe its cast iron and not mild steel plate, because of it porosity the moisture can weep into the whole piece rather than flaking from the outside in like steel plate would.

its definitely not cast iron... cast iron doesnt flake, it will be mild steel.

it could be that some previous owner may have raced the boat and thought more ballast might help them out, so they snuck in some extra ballast...

OR.. at some point the boat may have had a bit of a list that aggravated someones sense of aesthetics, and that was their way of trimming the boat..

there are better methods for both...

 

[kito]

My vote is it's just a piece of scrap steel plate left over by a PO doing some kind of project. A 5 x 8 piece of steel plate is easier to come by than a cast plate. Btw, I have never seen cast iron flake like that but seen plenty steel plates look exactly like that. As far as ballast....wouldn't there be more than just one 2lb piece?

 

[Ron20324]

Does it have a hole in it, like it could be used as an anchor rode kellet?

 

[centerline]

Cast iron most certainly does flake because there is more than one kind of cast iron (grey, white, ductile, etc.). The type used to make pots and pans is much stronger than they the type typically used to cast keels and such, it all depends on things such as carbon content. I haven't seen nearly the number of cast keels eroded away as I have seen engine blocks and trans cases, but yes they most certainly do flake. The way that piece pictured is separating like soggy cardboard leads me to believe its cast iron and not mild steel plate, because of it porosity the moisture can weep into the whole piece rather than flaking from the outside in like steel plate would.

not that this discussion makes any difference in all the world, except for those that want to know...
cast iron doesnt flake like the photo shows and will never flake like the photo shows, but mild steel does all the time.
and I never said cast iron doesnt corrode/erode away.
small flake or chip corrosion is possible but rare.

I work with all types of it, weld it, grind it, drill it, form it, and pour it/cast it when necessary.

there are 5 types of cast iron, and it has a much coarser granular structural makeup than does mild steel, which is why large multi-layered flaking is an impossibility with any type of it.... although, as has been shown with ductile pipe, when it is held in its shape by an outside force such as mud or clay in which it is buried, it can retain its shape and yet the iron content can completely erode away leaving only the alloys(the process of graphitization)... which can still weakly retain the original shape....

 

[Bob J.]

Thow it overboard. See how big a splash it makes. Post a video and you'll get lots of answers as to what it is (was) and what you should have done with it instead. The deeper the water the more valuable it will become.

I really like this. Made for a good laugh at the end of a lousy week.
Far as what that doodad is, no idea.

 

[Chief RA]

That is not a piece of CAST iron. Steel likely. Look up the definition of cast. Chief

 

[31seahorse]

Finding that piece of metal in a beloved boat should encourage each of us visit, inspect, clean up and organize all of those obscure places in our boat! Time for the vacuum cleaner, the scrubbing chemicals, lots of sponges and rags, and a good set of rubber gloves. I'm into a project like that even as we read.......

 

[EnginesForward]

Re: What the hell is this rust,
It looks like the swing keel steel plate that the keel of my Venture 22 which I just removed and had sand blasted. I agree that it is not cast iron and it does not look like it was caused by electrolisis. I was most likely used to protect the hull while prying or using a jack. There's an old saying in the Navy "A Sailor and Saltwater will screw up anything"!

 

[Kestle]

I think it was part of a piece of crap steel, used to nail on, ad grommets etc. A marine anvil of sorts.