View Full Version : Removing 66 yr old keel bolts...advice?

Martin Robel
06-06-2003, 12:43 AM
My seabird yawl's keelbolts are original and in questionable condition or worse. The bolts are (or WERE) galvanized iron and the wood they're in is douglas fir. The ballast keel is cast iron. I have made a preliminary attempt to remove one by cutting it in half with my 'sawzall' (through the gap between keel timbers) and trying to pry out the top half with a claw hammer (my pry bar is in storage). It just laughed at me. My next attack will involve a pipe wrench and attempting to rotate the thing, then prying on it. I did read the article about removing keel bolts in the current WB issue, but to use a jack I would have to devise a way to grab the end that does not involve unscrewing the nut which has become one with the bolt decades ago. Is there an easier way to do this?

06-06-2003, 02:54 AM
You'll find many here who share your pain. Put "removing keel bolts" (no quotes) in the search function in the upper right and you should find several helpful and humorous discussion on the subject.

Then there's our adventure:

Removing Keel Bolts (http://www.sailingwithsarah.com/removingkeelbolts.htm)

The webpage deals mainly with removing the keelbolts from the cast iron ballast keel. The deteriorated ones in the frames were hammered out through the bottom after removing the nut either by its designed means or via Sawz-all. Dave would then hammer from the top while I pulled/twisted from the bottom. Those were a cinch compared to getting the ends out of the ballast keel.

One of the best ideas I heard in one of the threads that should turn up if you do a search was the fact that if you're going to be replacing the floor anyway, it was fine to cut the floor to gain more access leverage on the offending keel bolt.

Happy pounding, pulling & swearing.

[ 06-07-2003, 10:59 PM: Message edited by: Concordia..41 ]

Andrew Craig-Bennett
06-06-2003, 01:35 PM
Er, yes, not a lot that I can add to that, but anyway...

If the nut won't play, cold chisel it off.

Use a BIG hammer - a smaller one is more likely to peen over the head of the offending bolt (same principle as using copper rivets, in reverse, so to speak)

As noted, have plenty of hard steel drifts.

I endorse the selfgrip wrench trick.

A good dose of penetrating oil may help - if only psychologically!

Good luck!

06-06-2003, 01:40 PM
I have written about my method before and if you do a search for Folkboat keel bolts it should come up.

Anyway I was replacing the floors, so I cut away some of the floor so that the bolt and nut were standing proud. I then cut a notch into a piece of angle iron and slipped it around the keel bolt, but that the nut rested on the sides of the angle iron. I then used the a jack to pull up the old keel bolt. It worked very well.

Good luck.


06-06-2003, 01:59 PM
I read that the easiest way the author had found to remove keel bolts, so much so that he ROUTINELY did so every so often in order to renew them, was to use 2 hydraulic truck jacks, one on each side of the bolt from the inside of the boat. You get the bolt free at the bottom, then you attach a sizable (he uses the handle of a huge monkey wrench) steel bar to the top of the bolt.. in his case he was able to use a screw in fitting, but you could tack weld it in.. and then jack away, one side at a time.

When metal is in tension, it gets thinner, thus the bolt would draw away from the hull, which aparently makes it much easier to remove them.

When metal is in compression, like when you are hammering it, it bulges outward so a keel bolt would tend to jam in its hole more tightly.


06-06-2003, 02:21 PM
The only other thing that I should add is that it took about 1 minute of the bolt being under tension to break free. Once it was loose I pulled it right out. I should mention that all I had to do was cut the nut off the bolt that attached inside the ballast. That way the whole bolt came out, not just the part that goes through the wood.

It also meant that I could do each bolt 1 at a time without dropping and moving that ballast around.


[ 06-06-2003, 03:22 PM: Message edited by: Noah ]

Andrew Craig-Bennett
06-06-2003, 03:35 PM
Some bolts come up and some only go down! The ones on my boat (which I have replaced twice in 19 years) have forged upset heads in the underside of the keel, so they will only drive down.

The reason for replacing them twice illustrates a huge difference between UK and US practice. In Britain, we routinely replace keelbolts, and most surveyors recommend doing this every ten years or so. If they are done thus regularly, they drive out pretty readily.

Floor to frame bolts (likewise iron in my case; the boat has wrought iron floors and an iron ballast keel) get renewed at the same time.

Martin Robel
06-07-2003, 02:04 AM
Thanks for all of the advice. I did go through and read most of the previous posts on this subject. It looks like I'll be trying the hydraulic jack method, even if it means carving away at the floors a bit. The construction is pretty robust so I think I can get away with that. I guess I was hoping someone knew of some easy solution I hadn't thought of or heard of (not including a big bon fire).