Rust spots on keel

[Aldis]

Hello fellow sailors!
I am viewing a boat this weekend and the current owner sent me some pictures of the rust spots on the cast iron keel. Although the owner claims the keel joint is free from rust - in the pictures I can see some stripping antifouling there and the wet spots on one side of the keel that look like traces of moisture coming out of the joint. The boat is currently afloat so I will not be able to check it myself - all i have is the pictures taken before the antifouling was applied. I know that hiring a surveyor would be the best option but for many reasons this is not feasible at the moment. Perhaps some of you have seen something like this before and could give me some advise on how serious this might be? I am attaching the pictures - please let me know your thoughts. Cheers!

[LittleWing77]

Hi Aldis,

Here's a recent thread from JonVonOrient September 2020 with keel + rust-related questions:

My First Sailboat
https://www.cruisersforum.com/forums...at-240139.html

Pay particular attention to boatpoker's advice and link. Boatpoker is a VERY experienced surveyor and has provided good info about rusting keels.

Please ensure for your own peace of mind that this boat does not have a catastrophic keel-rust problem before you purchase this boat! (The spots depicted do look to be more superficial, but you absolutely must make sure or you'll inherit a headache.)

Good luck and Fair Winds,
LittleWing77

[MicHughV]

rust on a cast solid steel keel shouldn't present a problem....clean, seal and paint.

but the joint is another matter. it appears to my eye, I see some rust spots at the joint. it's also unusual to see a caulking bead along the exterior of this joint, suggesting that this bead was put there after the original keel connection to hide something.

steel, when it rusts, also expands, and as an example, this expansion can cause a steel re-bar to pop concrete of a concrete beam.

in the case of the hull/keel joint, this expansion needs be only wafer thin to cause a separation to allow salt water ingress into this joint and cause a problem. Caulking can hide the problem, but not fix the problem. if this situation has been there for some time, the problem will grow proportionally.

additionally, a hard grounding can also be a problem for a keel/hull joint.

buying this boat, underbody sight unseen, is not a smart move in my opinion.

getting a boat surveyed, generally also involves hauling the boat out. yes, this is pain in the butt and an additional expense that you cannot recoup, should you decide to walk from the deal. boatyards that do this, typically hold the boat in the slings and give it a quick wash so as to better see things.
you don't have to be present, but certainly have an independent (not a seller's) surveyor take a look at this boat.

as LittleWing, above, suggests, do yourself a VERY big favor and get this boat surveyed, no ifs, ands and buts about it !!!!!