Hi all - Its my turn to ask the group for some help. I am about to undertake the installation of new keel bolts and would love to hear anyone's opinions. I have read everything I can find on the topic, including the archives here, but am always thirsty for more information. The boat is a 1980 Catalina 25, fixed iron keel, standard rig, traditional interior. Why do we pay surveyors? Mine looked at the bilge when I bought the boat last year and declared the keel bolts, nuts and washers sound but with surface corrosion, recommended cleaning them up and recoating them with a corrosion inhibitor. Wrong. The nuts on my keel bolts are shot. The washers are shot. There is substantial corrosion, and wastage, and I can flake away parts of the nuts with a screwdriver with little effort. From what I've read and what I've heard locally, I have concluded that the best course of action is to drill into the keel from the top and insert three new threaded rods (after tapping the holes) and to then install new washers and nuts. Its the procedure itself I'm not sure of. The keel happily attached at the moment. There is no Catalina smile. No indication that the keel hull joint has ever been compromised, no indication that salt water has ever gotten into the bilge from below. There is significant material remaining to the old nuts and washers, so I don't think the keel is in any danger of falling off at the moment, but I like to be sure. So, the questions. How do you drill cast iron? I have read about tapping the holes and also about doing them oversized and using epoxy, what do you think? How many do you think I need? I'm thinking three, between the four current keel bolt locations. What size rod do you think? Do I use stainless or iron, given that I'm going into an iron keel? What am I forgetting. I am operating on a student budget, so getting the yard to do this for me is out of the question, though I might be able to have them drill the holes and I would do the rest. I am planning on laying new roving in the bilge after drilling the holes and inserting the rods, then some cloth to clean up the appearence, then the washers and nuts. What do you think of that? I'd love to get your feedback - Justin - O'day Owners' Web - This time stressing about the Cat.
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david lewis
Keel bolts in cat 25
I had a catalina 25 and it had the same problem. The keel bolts just dinintegrate. This is a horrible design (cast iron keel). First of all while the boat is pulled and resting on her keel can you unbolt one of the keelbolts? Is the stud completely shot or just the nut? Using a carbide drill you should be able to drill out the existing bolt and then retap the hole and use the same hole. This would be easier if the keel is removed first but I don't know why you couldn't do it through the bilge if the keel to hull joint is sound. If you mess up the first hole you can always go oversize and put in a screw thread insert. You should use an adequate strength stud for this. I don't know what the original equipment studs are made from but they are not very corrosion resistant. This indicates perhaps a common steel or martensitic stainless which is strong but not very corrosion resistant. This method will eliminate drilling new holes. Most screws, bolts, studs, etc. are soft enough to be machined (drilled, etc) so I'd do this before drilling more holes in your boat. You can get threaded rod very readily but check a marina to make sure you use an edequate srength material. Also anyone with a lathe can make a stud threaded on both ends if you want a pilot diameter in the center section where it goes through the hull, you might coerce a student at a school (if they still teach metal shop) to make them. good luck. you might want to ask catalina what the original bolts are made of then use something better and more corrosion resistant. Lastly coat all threads in the keel with loctite neverseize or zinc chromate primer to prevent galvanic corrosion. d
I had a catalina 25 and it had the same problem. The keel bolts just dinintegrate. This is a horrible design (cast iron keel). First of all while the boat is pulled and resting on her keel can you unbolt one of the keelbolts? Is the stud completely shot or just the nut? Using a carbide drill you should be able to drill out the existing bolt and then retap the hole and use the same hole. This would be easier if the keel is removed first but I don't know why you couldn't do it through the bilge if the keel to hull joint is sound. If you mess up the first hole you can always go oversize and put in a screw thread insert. You should use an adequate strength stud for this. I don't know what the original equipment studs are made from but they are not very corrosion resistant. This indicates perhaps a common steel or martensitic stainless which is strong but not very corrosion resistant. This method will eliminate drilling new holes. Most screws, bolts, studs, etc. are soft enough to be machined (drilled, etc) so I'd do this before drilling more holes in your boat. You can get threaded rod very readily but check a marina to make sure you use an edequate srength material. Also anyone with a lathe can make a stud threaded on both ends if you want a pilot diameter in the center section where it goes through the hull, you might coerce a student at a school (if they still teach metal shop) to make them. good luck. you might want to ask catalina what the original bolts are made of then use something better and more corrosion resistant. Lastly coat all threads in the keel with loctite neverseize or zinc chromate primer to prevent galvanic corrosion. d
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Don Evans
Have A Superb Article For You
Written by an expert in keel replacing. Just published by a reputable marine magazine. Talks about all your concerns. If you want email me and I'll fax it to you. Don
Written by an expert in keel replacing. Just published by a reputable marine magazine. Talks about all your concerns. If you want email me and I'll fax it to you. Don
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Justin - O'day Owners' Web
My Fax number is -
Don - I'd appreciate a look at that article, sounds great. I just got an efax account, so hopefully it will work. The number is 413-280-1768. Thanks again, Justin
Don - I'd appreciate a look at that article, sounds great. I just got an efax account, so hopefully it will work. The number is 413-280-1768. Thanks again, Justin
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R.W.Landau
Catalina Smile?
Justin, What is the catalina smile? Sorry to hear your problem. Dave's advise sounds solid, and I wouldn't mind getting that article from Don. One thing I was wondering about was how did it get that bad. Bilge water or keel/hull joint. I would consider drilling and retapping the bolts, then breaking loose and reworking the keel hull joint. It's a job but, a 272 Oday wing was done right on the trailer last spring. If you haven't talked to Calatina , you might pursue it. Were the original bolts hooked or threaded in after the keel was cast? How have they resolved this problem? I know a catalina repairman comes here to Pittsburgh once in a while and does work on the many cat's in the area. They may even make a kit to do this or would consider putting one together for you for customer relations. I know its an older boat but how many have this same problem? Dave's point about the nut being your problem and not the stud could be a work saver. good luck keep us updated r.w.landau
Justin, What is the catalina smile? Sorry to hear your problem. Dave's advise sounds solid, and I wouldn't mind getting that article from Don. One thing I was wondering about was how did it get that bad. Bilge water or keel/hull joint. I would consider drilling and retapping the bolts, then breaking loose and reworking the keel hull joint. It's a job but, a 272 Oday wing was done right on the trailer last spring. If you haven't talked to Calatina , you might pursue it. Were the original bolts hooked or threaded in after the keel was cast? How have they resolved this problem? I know a catalina repairman comes here to Pittsburgh once in a while and does work on the many cat's in the area. They may even make a kit to do this or would consider putting one together for you for customer relations. I know its an older boat but how many have this same problem? Dave's point about the nut being your problem and not the stud could be a work saver. good luck keep us updated r.w.landau
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Rob Rich
CAT 27 - Similar
Justin - Similar case here. I am also a grad student, and recently purchased a 1979 Catalina 27. My surveyor mentioned that the keel bolts were "disappearing" (corroding away), but that the bolts themselves were okay. His reasoning was that the important structural part of the bolt was covered, either by the nut or by the keel itself. Therefore, there was no access to the bolt for water and air. I trust his opinion, as he was a production manager at C&C Yachts and is accredited. He told me simply to replace the nuts within a year or so, and to get better than production standard parts. For comparison, he was much more concerned that one of the batteries was not tied down. He also showed me that Catalina smile, (which was just barely visible) and mentioned that he saw it often - but as long as it was not excessive, that it would not cause a problem. However, I am interested in that article that you requested. If you could e-mail me a copy, I would greatly appreciate it. My e-mail address is below. Thanks - and good luck. Rob robrich@austin.rr.com
Justin - Similar case here. I am also a grad student, and recently purchased a 1979 Catalina 27. My surveyor mentioned that the keel bolts were "disappearing" (corroding away), but that the bolts themselves were okay. His reasoning was that the important structural part of the bolt was covered, either by the nut or by the keel itself. Therefore, there was no access to the bolt for water and air. I trust his opinion, as he was a production manager at C&C Yachts and is accredited. He told me simply to replace the nuts within a year or so, and to get better than production standard parts. For comparison, he was much more concerned that one of the batteries was not tied down. He also showed me that Catalina smile, (which was just barely visible) and mentioned that he saw it often - but as long as it was not excessive, that it would not cause a problem. However, I am interested in that article that you requested. If you could e-mail me a copy, I would greatly appreciate it. My e-mail address is below. Thanks - and good luck. Rob robrich@austin.rr.com
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Justin - O'day Owners' Web
Thanks Rob
Check out my other reply to this thread for details on my conversation with Catalina today. Justin - O'day Owners' Web
Check out my other reply to this thread for details on my conversation with Catalina today. Justin - O'day Owners' Web
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Justin - O'day Owners' Web
Todays episode
To those unfamiliar, the smile is the name given to crack that tends to develop at the keel/hull joint at the leading edge of the keel on some Catalinas. Other boats do it too; don't know what Catalina owners named the phenomenon. My boat is an early one (four years into a sixteen year run, I think). At the time my boat was built, Catalina used cast iron keels and mild steel studs and nuts. A couple of years later they went to lead keels with stainless hardware. Problem solved, except for those of us with early boats. My boat appears to have corrosion from blige water, but it would have had to have been standing for an awfully long time if so. There is no indication that water has every gotten in from below. The joint is intact and the keel sounds good when surveyed. I spoke with Catalina today. They ought to give lessons to other companies (boat and generall) about customer service. They tell me that the studs should be ok under the nuts, and that I should crack them off and check. I will do that tomorrow. I plan to do the worst one, and if the stud is ok to replace the washers and nut and do the others one by one. Wish me luck in not loosening the keel enough to knock my boat over; its in a yard surrounded by much more expensive boats. If I find that the stud is not ok, then things get more interesting. The only way the stud could be damaged below the nut is if water did get in from below at some point and traveled through the substrate. If so, the repair is more onorous. I will have to drill new holes into the keel for new bolts, then tap and insert rod. I will also have to hack out the plywood in the keelstub, and replace it with solid glass. Catalina actually suggests that this be done with the boat sitting on the keel, not with the keel removed, so that's one cost deleted. Anyone actually drilled a deep hole into cast iron? I have had posters on another board tell me to use oil, not to use oil, that it impossible, that its easy. Arg! Justin - O'day Owners' Web
To those unfamiliar, the smile is the name given to crack that tends to develop at the keel/hull joint at the leading edge of the keel on some Catalinas. Other boats do it too; don't know what Catalina owners named the phenomenon. My boat is an early one (four years into a sixteen year run, I think). At the time my boat was built, Catalina used cast iron keels and mild steel studs and nuts. A couple of years later they went to lead keels with stainless hardware. Problem solved, except for those of us with early boats. My boat appears to have corrosion from blige water, but it would have had to have been standing for an awfully long time if so. There is no indication that water has every gotten in from below. The joint is intact and the keel sounds good when surveyed. I spoke with Catalina today. They ought to give lessons to other companies (boat and generall) about customer service. They tell me that the studs should be ok under the nuts, and that I should crack them off and check. I will do that tomorrow. I plan to do the worst one, and if the stud is ok to replace the washers and nut and do the others one by one. Wish me luck in not loosening the keel enough to knock my boat over; its in a yard surrounded by much more expensive boats. If I find that the stud is not ok, then things get more interesting. The only way the stud could be damaged below the nut is if water did get in from below at some point and traveled through the substrate. If so, the repair is more onorous. I will have to drill new holes into the keel for new bolts, then tap and insert rod. I will also have to hack out the plywood in the keelstub, and replace it with solid glass. Catalina actually suggests that this be done with the boat sitting on the keel, not with the keel removed, so that's one cost deleted. Anyone actually drilled a deep hole into cast iron? I have had posters on another board tell me to use oil, not to use oil, that it impossible, that its easy. Arg! Justin - O'day Owners' Web
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david lewis
Keel Bolt Project
Machining cast iron is not a problem. Most machines are made with cast iron bases and then machined so industry has centuries of experience with this awful stuff. The bolts are just mild steel so a carbide drill should go right thru them like butter. As far as coolant or lubricants, my machinists handbook recommends a mineral oil or dry for the cast iron. As far as steel you should use a lubricant for two reasons, 1 to flush chips out and 2 to keep the tool and material cool. You don't want to start the epoxy on fire!!! Use a pecking process where you drill a little then pull it out and use a shop vac to suck out the chips then start again. Don't get too worried about the lubricant, you're not trying to make the drill last for 10,000 holes like in industry but use some type of lube! Be cautious of the studs even if they look ok after you remove the nuts. Are you using a nut splitter for that? I doubt a socket will grip the corroded edges of the nuts. There is a phenomenon in metallurgy called stress corrosion. Basically a metal under stress in the vacinity of moisture like in a thread in a wet keel will corrode and since threads are stress risers that will be the likely source of failure. I had a lower shroud through deck bolt break once on my Catalina 25, it sounded like a gunshot. A little water had gotten into the thread at deck level, otherwise the fitting looked fine but under a microscope it was apparent it had started corroding at the root of the thread and had progressed to the point that when a heavy load was placed on it the stress on the reduced area exceeded the ultimate strength and it failed. Quite an exciting experience but a quick tack relieved the load on the mast and all was aok. The replacement fitting by the way was a significantly larger size than the original equipment requiring drilling out the deck hole. At least I didn't lose the mast. Anyway check out the keel bolts well when you get the nuts off. If ok , new nuts with some anti seize compound and bedding compound should get you back in business. Why do they want you to dig out the plywood in the bilge? Is it rotted? This sounds like a pretty massive project but not too hard. the problem will be getting tools in there to grind out the GRP and the plywood, it is an oddball shaped area. I've seen a tool on TV called a rotozip (available at hardware stores) that might be useful for this if you can get bits long enough. good luck dave
Machining cast iron is not a problem. Most machines are made with cast iron bases and then machined so industry has centuries of experience with this awful stuff. The bolts are just mild steel so a carbide drill should go right thru them like butter. As far as coolant or lubricants, my machinists handbook recommends a mineral oil or dry for the cast iron. As far as steel you should use a lubricant for two reasons, 1 to flush chips out and 2 to keep the tool and material cool. You don't want to start the epoxy on fire!!! Use a pecking process where you drill a little then pull it out and use a shop vac to suck out the chips then start again. Don't get too worried about the lubricant, you're not trying to make the drill last for 10,000 holes like in industry but use some type of lube! Be cautious of the studs even if they look ok after you remove the nuts. Are you using a nut splitter for that? I doubt a socket will grip the corroded edges of the nuts. There is a phenomenon in metallurgy called stress corrosion. Basically a metal under stress in the vacinity of moisture like in a thread in a wet keel will corrode and since threads are stress risers that will be the likely source of failure. I had a lower shroud through deck bolt break once on my Catalina 25, it sounded like a gunshot. A little water had gotten into the thread at deck level, otherwise the fitting looked fine but under a microscope it was apparent it had started corroding at the root of the thread and had progressed to the point that when a heavy load was placed on it the stress on the reduced area exceeded the ultimate strength and it failed. Quite an exciting experience but a quick tack relieved the load on the mast and all was aok. The replacement fitting by the way was a significantly larger size than the original equipment requiring drilling out the deck hole. At least I didn't lose the mast. Anyway check out the keel bolts well when you get the nuts off. If ok , new nuts with some anti seize compound and bedding compound should get you back in business. Why do they want you to dig out the plywood in the bilge? Is it rotted? This sounds like a pretty massive project but not too hard. the problem will be getting tools in there to grind out the GRP and the plywood, it is an oddball shaped area. I've seen a tool on TV called a rotozip (available at hardware stores) that might be useful for this if you can get bits long enough. good luck dave
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Don Evans
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R.W.Landau
Don, scanner?
Don, If you have a scanner, my e-mail address is rwlandau@aol.com. My fax setup is screwie. thanks Don r.w.landau
Don, If you have a scanner, my e-mail address is rwlandau@aol.com. My fax setup is screwie. thanks Don r.w.landau
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Justin - O'day Owners' Web
Got it! Thanks. RW - I have them as jpegs . . .
that I can send to you. I'll try to send them. We'll see if my mailserver is ok with the file sizes. Love my efax. Justin
that I can send to you. I'll try to send them. We'll see if my mailserver is ok with the file sizes. Love my efax. Justin
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john renfro
drill
hi justin, if you start drilling holes be sure you , as david suggests, peck at it. at some point the drill will take off and cut like magic but if you don't stop and remove the chips, they will pack up in the flutes in the drill and you will snap the bit off leaving it in the hole and you can't drill out a drill bit. good luck john
hi justin, if you start drilling holes be sure you , as david suggests, peck at it. at some point the drill will take off and cut like magic but if you don't stop and remove the chips, they will pack up in the flutes in the drill and you will snap the bit off leaving it in the hole and you can't drill out a drill bit. good luck john
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