Stainless Steel Keel corrosion

I’m new to the forum and to the NC700. We have found extensive corrosion on our keel.
• The base is severely corroded from the midpoint to the aft end (the stainless steel outer has corroded away completely).
• There are a three or four areas of crevice corrosion aligned vertically with one of the internal ribs the highest being most of the way up to the keel head
• Drilling a hole just above the foot produces a brown mush instead of shiny lead swarf.

I’d like to avoid the conclusion that I need a new keel. Does anyone have successful experience of repairing this (or of replacing the keel ) ?

Thank you .

Hmm the description looks horrid, maybe if you post some pictures you can get a more specific advice on how to tackle this issue.
Replacing a keel can be done, you need someone to copy the keel, so that means drawing the structure, defining the required weight and having it constructed. But most keel issue’s I have seen thus far on this forum require either replacing the top construction (the stainless part that connects to the lifting cable) or replacing the coating of the keel. When your ship is used in salt water the damage of corrosion may be more severe, we are mostly inland sailors :wink:
Oh and most welcome to our humble dwelling on the interweb off course!

Thank you for the reply and the welcome ! I’ll attach a couple of pictures from when the keel was still on the boat. One showing the damage to the foot (looking upwards from below) and the other an example of crevice corrosion (which follows the connection to the internal vertical rib).

The keel is with a stainless steel specialist to get a price to do exactly what you suggest - do you know if anyone else has done this (I’m hoping not to be the first…) ? However if anyone has successful experience of a repair then please let me know.

The keel box looks to be in good condition, but it may still be more cost effective to replace it.

The lower corrosion (and crevice corrosion) does look more advanced than expected, even for a saltwater boat. I’m wondering if stray currents from the earth strap to the rigging may have contributed ? We plan to fit anodes to the new keel if that’s the way we have to go.

Finally, I think the lead only fills part way up the keel. Does anyone know the overall weight, and also what the void space above the lead is filled with ?

I dont know for the new classic but my keel weighs in at 230 kilo’s as far as I know
Here is another thread on this forum with pictures of a keel repair on a new classic 700 Schade kiel New Classic 700 - Technical Matters -

Hey, my keel is also stainless steel filled with the bottom part filled with lead. I don’t think the top part is filled with anything. Air if airtight but else it will fill up with water. It is hard to tell if it empties out when hauling it out of the water as the water from the hull follows the same path.

Anodes helpt volgens mij niet tegen spleetcorrosie.
Google maar ff, maar de rvs boer weet het wel
Die kiel weegt ook volgens mij 230 kg
Boven het lood is de kiel leeg, met een kleine lekkage ergens loopt hij vol water

Stond in de laatste Zeilen een heel verhaal over kiel problemen, alleen maar vaste overigens. Maar ze meldden volgens mij ook dat RVS op de een of andere manier nog weer vatbaarder was voor spleetcorrosie.

I think it is correct that stainless steel is more susceptible to crevice corrosion - the material inside the crevice does not form a protective oxide layer so it acts as an anode “protecting” the rest of the surface. I (hope) this also means that provided the anode material is more active than the stainless steel in the crevice it should provide some protection.