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Columbia 36 keel bolts

Feb 8, 2014
1,300
Columbia 36 Muskegon
This fall I bit the bullet and dropped the keel to change the bolts. Boat's now in fresh water but had spent at least 30 years in salt. The tops of the bolts were very rusty and rusty water would seep out of the hull/keel joint on haulout. Very bad signs. The PO's had attempted to seal the joint with fiberglass tape, but unless an inch or more of glass is laid on, that can't work.
The keel is lead so the greatest worry was how to replace the bolts. Most lead keels have "J" bolts cast into the lead, making them almost impossible to replace. I had read some threads here saying Columbia used a harder alloy of lead on this model allowing them to thread hanger bolts directly into the keel. Well, I found out that this is correct. There are nine 3/4" x 11" hot dip galvanized hanger bolts threaded through 4" of glass and about 5" into the lead. The part threaded into the glass and lead looks brand new, just the tops rusted off. The forward bolt where the leak was is basically gone.
When I removed the nuts I found that the bolts were rusting out from under them, and they were barely more than finger tight. Once the nuts snapped loose, they lifted right off the bolts as there was no more thread to hold them. The forward most bolt broke off when i turned the nut. I have to wonder if the keel would have stayed on another season.
I used a bolt extractor to pull the bolts and they came out without much difficulty. After grinding off the fiberglass repair attempt the travel lift came back and lifted the hull off the keel. It came apart with no resistance. Surprisingly a lot of the original sealant ( I'm assuming this was the first time the keel was dropped) was still gooey after 47 years. Appears to be 5200 or similar.
I haven't found new hanger bolts that large so I plan to use lag bolts which are available. A ten pack of 9" hot dipped 3/4" bolts for $28 plus shipping from BoltDepot.com. Stainless would run $40-50 each. Hot dipped has lasted 47 years so far where not exposed to salt water so that's what I'm planning to use. They should thread into the original holes so I will only have to redrill the one hole for the broken bolt, and since it's a ten-pack I'll add one more. I may drill the holes a bit deeper and use longer bolts for good measure.

So far this project has gone much better than I imagined, and would recommend anyone with dodgy keelbolts to give it a go.
 
Feb 8, 2014
1,300
Columbia 36 Muskegon
Holes were already tapped from the original bolts. Just screwed the new ones in. As added insurance I coated the threads with silica thickened epoxy first. I don't think they'll be coming out. The forward bolt was broken off below the surface of the lead and I couldn't extract it, so I sistered it. Drilled a new hole next to the old one, 1/2" as I recall and screwed the lag bolt in. The bolt cut it's own threads, just like you would do in wood. It's been several years now and all's good.
 
Dec 21, 2020
12
Columbia 28 Oxnard
there is a access way to an empty compartment just below the table on my c28. It s a nice circle with a screw in cover. Does anyone know what was this for?
 
Dec 21, 2020
12
Columbia 28 Oxnard
Holes were already tapped from the original bolts. Just screwed the new ones in. As added insurance I coated the threads with silica thickened epoxy first. I don't think they'll be coming out. The forward bolt was broken off below the surface of the lead and I couldn't extract it, so I sistered it. Drilled a new hole next to the old one, 1/2" as I recall and screwed the lag bolt in. The bolt cut it's own threads, just like you would do in wood. It's been several years now and all's good.
I left mine in and added, by sistering, 6 new stainless hanger bolts in. Couldn't find suitable ones so had custom ones made. I have extras if anyone needs them, let me know.
 
Oct 22, 2014
15,712
CAL 35 Cruiser moored EVERETT WA
@themotorman
Not sure if you found this detail about the Columbia 28 when your redid your keel bolts.

From: Columbia 28 Specifications

Like many older fin keel boats, some C-28 owners have had to replace corroded keel bolts. Here is some info on the bolts for this boat from a manual dated January 1972.

There are seven keel bolts. These are lag bolts installed from the top. (3/4" DIA X 9" LG LAG STUD. DRILL .656" DIA X 5" DEEP USING C-28 KEEL ATTACHMENT JIG FOR POSITIONING HOLES. USE LAG END OF STUD AS TAP TO THREAD KEEL. APPLY KEROSENE TO HOLE AND STUD DURING TAPPING OPERATION. USE CAM-TYPE STUD DRIVER. LEAVE 4" MIN. OF STUD PROTRUDING FROM TOP OF KEEL. - 7 REQUIRED.)

Also concerning the nuts: 3/4" NC HEX NUT & 3/4" ID X 2" OD PLAIN WASHER - HOT DIP GALV STEEL DRILL 13/16" DIA THRU HULL USING SAME KEEL ATTACMENT JIG FOR POSITIONING HOLES AS IS USED TO DRILL KEEL. (SEE DETAIL) - 7 PLACES
 

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