Crack in hull bottom

[BoatBum]

I was starting to get my 1985 Hunter 25.5 shoal draft ready for a bottom job when I noticed a crack. The crack area is about 2.5 inches in size and the material involved appears to be iron. Must be part of the keel structure. I can recall no groundings or encounters with objects in the water, so I have no idea of the potential source. Any ideas concerning repair? While the area involved is rather small, I am quite concerned over possible loss of stuctural integrity. Wouldn't be good to lose a keel!

The separation that is apparent in the photos is not as bad as it looks, but there is separation.

 

[Ed Schenck]

Need a little better description of the area. From the picture it looks like loose lead. Is it just near the joining of the bulb to the vertical?

 

[BoatBum]

For Ed

Need a little better description of the area. From the picture it looks like loose lead. Is it just near the joining of the bulb to the vertical?

The keel on this boat is cast iron. The crack is actually on the bottom of the boat a few inches laterally from the keel itself. I originally thought the bottom would be fiberglass in the area of concern, but it appears that there is a metal plate of some sort affixed to the bottom of the boat and extending a bit laterally. I should note that there has been no keel bolt leaks and the bolts themselves are checked for proper torque each year. The metal at that location was a surprise.

 

[Ed Schenck]

I understand your description but not really. My keel, which is lead, attaches to a stub. That stub is solid fiberglass. You are saying that part of your hull extending out from the stub is metal? I have to say it does look that way in your pictures. It at first glance does not look like a boat bottom, more like a keel. So I guess it must be metal. I hope someone has seen a similar problem and fixed it.

 

[BoatBum]

Me too!!! Thanks Ed.

 

[Ed Schenck]

Here's something similar: http://forums.hunter.sailboatowners.com/showthread.php?p=687468&highlight=keel . Not sure why this showed up on an H25.5 search. But this discussion about fairing caught my eye. Did Hunter fair it using some kind of "bondo" like material? Or maybe a previous owner? I guess I would break away all that was easily removed and refill. Still think someone must have seen this.

 

[BoatBum]

I don't believe the material is a fairing compound - there is some rust that is not seen very well in the photos and the material appears to be a metal. I sent a note to Hunter and hope they can get me on the right path. I am also going to pull off a sample tomorrow to get a better handle on the material. Thanks again, Ed. If it is a fairing compound, I willbe a happy camper.

 

[jtm]

let us know what you learn about the material- you can't be the only person with the experience.

 

[BoatBum]

I have learned a bit more. First, Ed's thoughts concerning fairing materials proved correct. I went to the boat, popped a magnet to the area having the cracking, and the magnet stuck to the hull. I then pulled off some of the cracked material and put the magnet on it. It did not stick. Sure does look metalic, though.

Hunter contacted me and gave me some good information. It turns out that a part of the keel, called an "ear" is present for a short distance laterally from the keel in four locations on the bottom of the boat. The ears help fix the keel to the hull. In my case,water has found its way between a layer of epoxy (fairing) that is applied to cover the keel ears. I expect it is a secondary result of a lightening strike a nember of years ago. If the ears was separated from the epoxy during that event, it was not located and repaired when the many repairs were made. In any event, the iron ear has been slowly corroding for some time. This winter the combined pressure of the iron oxide formation and freezing water finally popped the epoxy layer forming the observed cracks.

I pulled a good deal of the epoxy layer off from the cracked area. The iron ear is heavily rusted, but still appears structurally sound. I intend to remove the epoxy layer far enoung way from the cracks to find sound adhesion between the epoxy and whateveris under it at that point. Then I will feather the edge of the epoxy layer, wire brush the rusted ear, use a rust remover of some sort, put a corrosion preventer and primer on the metal, fill and fair with West System and then do the originall planned bottom job.

If I run into anything that I think others might find useful, I'll pass it on. Thanks to all, especially Ed, for the help.