SailNet Community banner
1 - 3 of 3 Posts

·
Registered
Joined
·
25,128 Posts
Since the quote reads "grind keel rust to bare metal", it makes me think this is a spot repair and a complete waste of money. Once an iron keel starts to have that many issues, I think it's best to do it over.

First, it should be soda blasted down to bare metal, then immediately primed with an etching primer of some sort. The mold imperfections will then need to be refaired, then epoxy barrier coat. Then, of course, antifoulant. I had all the above done on a 54ft Jeanneau for about $5k and RI is well known to be high cost. Cure temperatures and times are critical!! Be sure the yard follows them. I needed a warranty repair done the following year on a 4sqft area.

The rust at the keel joint is what would get my attention the most. The keel flexes against the flat bottom, so rust on the outer surface of the joint is common. You want to know if sea water has breached the bedding adhesive and reached the keel bolts. Hoepfully not. As Jeff said, I'd check a few, if not all of them. You might make this a project to replace them, as you check them. I did that too, from the inside of the boat. They are a wear item.

Then, I would fair that cleaned up keel joint with 3M 5200 and don't be stingy. I good inch wide. I tried several other things over the years and this was the only one that worked.
 

·
Registered
Joined
·
25,128 Posts
Did you find corrosion on the keel bolts?
Not below the bilge. Part of my motivation was notable corrosion on the studs and nuts that were above the bilge. I was pleasantly surprised to see the threads actually hold the keel on were sound. Although, felt better to replace the rusting nuts and backing plates too.

How long after the rust appeared at the top edge of the keel did you inspect the bolts?
Quite a number of years. Rust at the top edge of an iron keel is too normal to rush to judgement, unless it's really bad.

Why does the keel joint flex?
It wouldn't take much more than a microscopic crack to allow ingress of salt water, which is also under pressure a couple feet below the surface.

Our iron keel weighed 11,000 pounds and had an athwartship section of maybe a foot? 18 inches max, by memory. When heeling to one side, that kind of lever against a flat hull is just going to open an unprotected seam. It needs to be faired and sealed. I don't know why they don't come that way from Jeanneau, as their instructions for rebedding the keel include them. Could be that local yards bed the keel and do it wrong. Perhaps to your point, you don't need to allow for super flexible sealant, as it's shouldn't move much.

My keel is iron as well. However the keel has an integral cast flange which is about 1 or more inches thick and extends forward, aft and to the sides of the keel forming a very large plate for load distributing and bearing.
I'm not really following what you have. Maybe it's like what I now have. We have a keel stub that extends below the hull. The keel is bolted to the stub and their is a groove between the two, which is designed to be filled with a flexible caulking/adhesive to take up an movement. This is different from the 90 deg seem in the OPs pic. It's a parallel seam/groove.
 
1 - 3 of 3 Posts
Top