Keel eye bolt tapping – fail

Although it’s been great making progress on the keel, I’ve run into another issue that’s going to slow me down.  (As if I could possibly go any slower)   It’s the keel eye bolt.

Unexpectedly, the re-tapping of the keel eye bolts did not go so well.  The welder came over and brought his tap.  He oiled up and started screwing it in.

Tapping the keel

It went only so far, then stopped.

Keel tapped out

The eye bolt didn’t fit all the way.  At first I thought I might leave it like that, then $tingy Sailor suggested I might cut the threads off so it would be flush and not have any exposed threads.  This seemed reasonable, so I went out to do it.  Taking a closer look made me rethink the whole thing.

Tap looks good

Looking at one angle makes you think the tap went pretty well, but ….

Not so well

 

From the other angle you can see that there are only 3 threads on the other side.  Not near enough to trust with the weight of the keel.  It looks like there is actually some corrosion or a void so there is no metal to tap into.

So, it’s back to the drawing board.  I have a plan though.

  1. Buy a bit and tap
  2. cut a notch behind the original eye bolt location
  3. redrill, retap, put in new eye bolt flush to surface
  4. Have sandblaster do the entire keel, including hole.
  5. seal the entire thing in epoxy.
  6. Finish fairing and painting.

Here is an old picture marked up to show where the new cutout is going (red) and the current cut that was done (yellow)

proposed eye bolt location (red)

Anything I’m missing?  Any suggestions?  Will it be a problem if it doesn’t line up directly under the keel cable hole?

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11 thoughts on “Keel eye bolt tapping – fail

    • You’re right, it was a taper tap. However, that was only part of the problem. The threads are fine down one side of the hole, but then there’s only 3 on the other side due to what looks like corrosion on the side of the hole. It’s really hard to tell what’s going on in there. I can’t really get a good look.

  1. It’s hard to tell how extensive the corrosion is from the photo but it doesn’t look extreme. My suggested fixes would be (in preferred order):

    1. Drill and tap deeper and try to get the first half inch of eye bolt threaded below the corrosion and use thread sealant liberally. If that destroys the upper threads in the process or as a first alternative, drill and tap oversize, then install a helicoil insert to get back to your original diameter. Helicoils have been used for decades to repair stripped engine block bolt holes.

    2. Fill and redrill.

    3. Drill a new hole like your plan.

    Any of those will work equally well. It’s your choice.

    • Thanks for the suggestions. I’m going to go with a modified #1. What do you think about getting an oversized eyebolt online and drilling big enough hole to get to clear metal, then tapping new threads? I can get a stainless eyebolt rated at 5,000 lbs – it just won’t look like the original bolt. Would you prefer the helicoil over just trying to oversize the bolt?

  2. personally, I would get your welder to cut out and weld up the hole where the original eyebolt went. He can then tap fresh metal and everything can be as safe and sound as can be made. Much like rigging, a swing keel is not something you want to take a chance on.. it that eyebolt were to fail, the amount of damage it can cause as it falls down and swings directly into the brittle ‘glass of your boat can crack or even destroy the trunk and sink your boat.

    Please do it right

  3. Since your thinking of abandoning this freshly tapped hole, I would suggest trying JB Weld steel first ($12). This would give you more threads. Take a little bit of the putty and kneed it till it is one color and then stick it in the threaded hole and press it into the void and then quickly thread the eye bolt into place. WARNING: JB Weld Steel has a 3minute pot life. So you will need to be very quick about this. Even test a small piece of JB Weld somewhere else on the keel to wrap your brain around how fast this stuff sets up and how hard it is afterwards. My friend used JB Weld Steel to secure his bushing around the keel pin, and has been sailing that Cat 22 for over a year now without any problems. If this gets screwed up, just think, you were planning on abandoning this hole anyways.
    I personally knocked off the scale from my keel using just a hammer. Once the large chunks were off, I attached a wire brush to my angle grinder and went over the keel two~three times and applied OSFO to stop the rust. Then seal, fair, seal again. If I were to do it again, that is what I would do with the added fairing shape that $tingy Sailor provides on that blog.

    • Thanks for taking the time to help me out with a suggestion. I’m actually thinking I’ll do $tingySailor’s suggestion of drill and tap deeper. We’ll see how that goes. I’ll do a bit of research and then post what I’m planning to do before I actually make any changes.

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