Hello everyone, My name is Robert, and I am looking to buy a Cherubini 37 cutter. Like the last guy to post on this forum, I am also an engineer, and have already rebuilt several boats. I cannot find any information on the keelbolts they used (material), or what kind of keel to hull joint was used. Are the keelbolts buried under a water tank? Has anyone had trouble with the keelbolts on these models? Any information sent would be appreciated. Thanks in advance, Robert.
Hunter Cherubini Keelbolts
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keelbolts
Not anywhere near an expert, but we have been living on (in) a 37c for nearly 20 years. The keelbolts are SS, and I believe they are J-shaped into the cast-lead keel. By my inspection, they are 3/4", and are snugged into the keel stub with nuts and washers. I have yet to hear of any problems with the joint or the bolts. They are robust. The keel on our '81 is a modified Scheel that draws just 5', and I think it would take the ground as well as any boat in her class...or out of it, for that matter. Dave
Not anywhere near an expert, but we have been living on (in) a 37c for nearly 20 years. The keelbolts are SS, and I believe they are J-shaped into the cast-lead keel. By my inspection, they are 3/4", and are snugged into the keel stub with nuts and washers. I have yet to hear of any problems with the joint or the bolts. They are robust. The keel on our '81 is a modified Scheel that draws just 5', and I think it would take the ground as well as any boat in her class...or out of it, for that matter. Dave
avalonduet got it right
When we had the boat in for some repaier from a keel strike, the yard super also made these observations: The number of keel bolts, the fiberglass layup, and the grid of glassed in frames in the Cherubini's are all well beyond toay's standards. Lack of knowledge about the material made them conservative in the 70's. So the keel is _very_ solidly attached to a very stiff hull. David Lady Lillie
When we had the boat in for some repaier from a keel strike, the yard super also made these observations: The number of keel bolts, the fiberglass layup, and the grid of glassed in frames in the Cherubini's are all well beyond toay's standards. Lack of knowledge about the material made them conservative in the 70's. So the keel is _very_ solidly attached to a very stiff hull. David Lady Lillie
So Far So Good
Thank you both for your replies. I really like the part about the glassed in frames. Do you know if the keelbolts come up through the frames? One of the problems with the Catalina 38's arose from Butler's chincy use of material. He weakened Swan's hull by removing some of the structural design around the mast and also aft around the pedestal. The result was oil canning when driven hard and a wheel that feels like it could part with the deck at any moment. The problem with stainless keelbolts, especially those that cannot be removed and checked (like in the old days) is that stainless of any grade is susceptible to having the protective passivation layer stripped off by chlorides. It is oxygen which will again create the passivation layer, but in a putrid bilge containing salt (sodium CHLORIDE) and no oxygen, stainless keelbolts could be in trouble. When talking to Catalina, they remarked how they reccomended drifting new bolts into the keel, and how they haven't lost a keel....yet! Having the bolts come up through a fibreglass frame would be a real plus, as would a boat from the Great Lakes. The all should have spent the extra money and used monel. But note that as long as the top of the keel stub is accessible, it is not too diffucult to bore and tap the keel to install new bolts. On we go, Regards, Robert.
Thank you both for your replies. I really like the part about the glassed in frames. Do you know if the keelbolts come up through the frames? One of the problems with the Catalina 38's arose from Butler's chincy use of material. He weakened Swan's hull by removing some of the structural design around the mast and also aft around the pedestal. The result was oil canning when driven hard and a wheel that feels like it could part with the deck at any moment. The problem with stainless keelbolts, especially those that cannot be removed and checked (like in the old days) is that stainless of any grade is susceptible to having the protective passivation layer stripped off by chlorides. It is oxygen which will again create the passivation layer, but in a putrid bilge containing salt (sodium CHLORIDE) and no oxygen, stainless keelbolts could be in trouble. When talking to Catalina, they remarked how they reccomended drifting new bolts into the keel, and how they haven't lost a keel....yet! Having the bolts come up through a fibreglass frame would be a real plus, as would a boat from the Great Lakes. The all should have spent the extra money and used monel. But note that as long as the top of the keel stub is accessible, it is not too diffucult to bore and tap the keel to install new bolts. On we go, Regards, Robert.
I agreee with the so far so good!
Having purchased my 1981 37' cutter in July of 05 I was very curious about the state of the keelbolts. After several other pressing projects I took a hard look at the keelbolts. The survey didn't necessarily say anything about the condition of the bolts. After carefull observation (mine are 3/4" bolts with 1" 1/8" nuts) I was a little concerned about them. I spoke with someone from Hunter, they informed me that the bolts are 18" into the keel in a "J" shape. The keel is then fitted to the boat and sealed with West epoxy. This gentlemen had been with Hunter 20 something years and could not remember any of the 37's ever having a keel problem. He also mentioned that if I had a problem with them weeping. To remove the nut and washer (one bolt at a time) and to dremel around the bolt and to use "keel cotton" around the bolt and seal with 3m 5200. Sounds like a good solution, even though I haven't try it yet, as mine aren't weeping. Basically all I have done is clean them with a stainless steel wire brush. I am in the process of looking for something I can put on/over them to seal them from the water in the bilge. Best of Luck
Having purchased my 1981 37' cutter in July of 05 I was very curious about the state of the keelbolts. After several other pressing projects I took a hard look at the keelbolts. The survey didn't necessarily say anything about the condition of the bolts. After carefull observation (mine are 3/4" bolts with 1" 1/8" nuts) I was a little concerned about them. I spoke with someone from Hunter, they informed me that the bolts are 18" into the keel in a "J" shape. The keel is then fitted to the boat and sealed with West epoxy. This gentlemen had been with Hunter 20 something years and could not remember any of the 37's ever having a keel problem. He also mentioned that if I had a problem with them weeping. To remove the nut and washer (one bolt at a time) and to dremel around the bolt and to use "keel cotton" around the bolt and seal with 3m 5200. Sounds like a good solution, even though I haven't try it yet, as mine aren't weeping. Basically all I have done is clean them with a stainless steel wire brush. I am in the process of looking for something I can put on/over them to seal them from the water in the bilge. Best of Luck
Let us pray there are no weepers!
A weeping keelbolt in a fibreglass boat would be a sign of major problems. First of all, if the keelbolt was of stainless, and I emphasize the WAS, it would certainly be rotted. Second, the keel to stub seam would be the culprit, indicating a probably moving keel, indicating bending of what was left of the rest of the keelbolts, certainly leading to the keel dropping off the boat sooner than later. There is a reason why it isn't ofter that we hear of a keel dropping off the bottom of a boat! They don't have a prayer of coming back! Using West to seal the keel is interesting. I think 5200 would provide a better seal. If any of you are worried about your keelbolts, hammer (chisel) a fore and aft mark to the top of the bolt and then put 200 ft-lbs to the nut with a torque wrench. If the bolt twists, it is toast! You might also take the nut off before torquing it to check the threads for pitting. If you find none, put a bead of 5200 around the bolt, seal the nut threads with the best thread sealer you can buy, and THEN torque the bolt to 200 ft-lbs. I am going to talk to Hunter to see if anyone has dropped the keel to inspect. Now THAT would be interesting! Regards, Robert.
A weeping keelbolt in a fibreglass boat would be a sign of major problems. First of all, if the keelbolt was of stainless, and I emphasize the WAS, it would certainly be rotted. Second, the keel to stub seam would be the culprit, indicating a probably moving keel, indicating bending of what was left of the rest of the keelbolts, certainly leading to the keel dropping off the boat sooner than later. There is a reason why it isn't ofter that we hear of a keel dropping off the bottom of a boat! They don't have a prayer of coming back! Using West to seal the keel is interesting. I think 5200 would provide a better seal. If any of you are worried about your keelbolts, hammer (chisel) a fore and aft mark to the top of the bolt and then put 200 ft-lbs to the nut with a torque wrench. If the bolt twists, it is toast! You might also take the nut off before torquing it to check the threads for pitting. If you find none, put a bead of 5200 around the bolt, seal the nut threads with the best thread sealer you can buy, and THEN torque the bolt to 200 ft-lbs. I am going to talk to Hunter to see if anyone has dropped the keel to inspect. Now THAT would be interesting! Regards, Robert.
Slight Correction
I just checked a torque guide for a 3/4 stainless bolt, and found the low end to be at 175 ft-lbs, so you should stop there. Regards, Robert.
I just checked a torque guide for a 3/4 stainless bolt, and found the low end to be at 175 ft-lbs, so you should stop there. Regards, Robert.
Not through the frame
The role of the grid of glassed in timbers is to stiffen the bottom of the hull, and in fact, the whole hull structure. The glass between the beams is far more than capable of carrying the keel, and is a much better structure for the keel bolts. Compression loading the beams from the side would degrade the beams, and allow loosening of the keel bolts over the long term. Again, relax. After over 20 years, if the keel attachment was a problem, we would know about it! David Lady Lillie
The role of the grid of glassed in timbers is to stiffen the bottom of the hull, and in fact, the whole hull structure. The glass between the beams is far more than capable of carrying the keel, and is a much better structure for the keel bolts. Compression loading the beams from the side would degrade the beams, and allow loosening of the keel bolts over the long term. Again, relax. After over 20 years, if the keel attachment was a problem, we would know about it! David Lady Lillie
Be Careful With This
Thank you all for your replies. Hunter has responded with 132ft-lbs of torque, which is the standard torque listed for a 3/4 inch stainless bolt. Using a torque calculator with the load from the keel in the equation, the torque comes out to 186ft-lbs. Believe it or not, 3/4 inch bolts for a 7000lb keel is definetly on the light side. Note that to torque the nuts the load must be taken off them, meaning the boat must be hauled out and the keel supported. What would I do with my own boat? First of all I wouldn't even buy a fibreglass boat with weeping keelbolts. If they began weeping while I had the boat, I would have no choice but to drop the keel, inspect the bolts, and reseal it. Second, I would absolutely remove the nuts, check for pitting, seal the base of the bolt, and retorque the nut with thread sealer, one nut at a time. I would be very careful about tightening the nuts, probably stopping every 25ft-lbs after 100ft-lbs to check for twisting. The bolt should easily take 150ft-lbs, (note the max from the calculator is 258ft-lbs), without any twisting or cracking sounds coming from the stub. Third, if there were problems found, like pitting, twisting, or obviously wasted bolts, WITHOUT ANY WEEPING, I would bore and tap at least six 1 inch monel bolts into the keel. These bolts are your life! Take care of them! Regards, Robert.
Thank you all for your replies. Hunter has responded with 132ft-lbs of torque, which is the standard torque listed for a 3/4 inch stainless bolt. Using a torque calculator with the load from the keel in the equation, the torque comes out to 186ft-lbs. Believe it or not, 3/4 inch bolts for a 7000lb keel is definetly on the light side. Note that to torque the nuts the load must be taken off them, meaning the boat must be hauled out and the keel supported. What would I do with my own boat? First of all I wouldn't even buy a fibreglass boat with weeping keelbolts. If they began weeping while I had the boat, I would have no choice but to drop the keel, inspect the bolts, and reseal it. Second, I would absolutely remove the nuts, check for pitting, seal the base of the bolt, and retorque the nut with thread sealer, one nut at a time. I would be very careful about tightening the nuts, probably stopping every 25ft-lbs after 100ft-lbs to check for twisting. The bolt should easily take 150ft-lbs, (note the max from the calculator is 258ft-lbs), without any twisting or cracking sounds coming from the stub. Third, if there were problems found, like pitting, twisting, or obviously wasted bolts, WITHOUT ANY WEEPING, I would bore and tap at least six 1 inch monel bolts into the keel. These bolts are your life! Take care of them! Regards, Robert.
Sturdy
Check out the plans for the 37C and the 36 (80-82) and you will see these boats are very similar except for cutter rig and a few minor differences. Our 36 survived Katrina well landing against a pine tree and standing on the keel after the surge departed. (the pine tree graciously held on to the mast to help) She has a cosmetic joint separation at the keel stub seam. There was no visible damage to the glass below the bolts and washers. These hunters are sturdy boats.
Check out the plans for the 37C and the 36 (80-82) and you will see these boats are very similar except for cutter rig and a few minor differences. Our 36 survived Katrina well landing against a pine tree and standing on the keel after the surge departed. (the pine tree graciously held on to the mast to help) She has a cosmetic joint separation at the keel stub seam. There was no visible damage to the glass below the bolts and washers. These hunters are sturdy boats.
Need the Plans!
Hi Jim, I went to Hunter looking for plans for the 37C and was told plans or drawings are no longer available. How complete are the plans you have? Specifically what I am looking for is whether Cherubini used plywood "stuffing" inside the keel stub instead of more expensive fibreglass. There are reasons why a Swan is a Swan. Catalina did this on their (Swan mold) 38's and it was a disaster. These boats were built around the same time. Somtimes the smaller boatbuilders cut the wrong corners! If your plans are complete I would like to have a copy of them. Could you post them on this site? Could you email them to me? Let me know! Thanks, Robert.
Hi Jim, I went to Hunter looking for plans for the 37C and was told plans or drawings are no longer available. How complete are the plans you have? Specifically what I am looking for is whether Cherubini used plywood "stuffing" inside the keel stub instead of more expensive fibreglass. There are reasons why a Swan is a Swan. Catalina did this on their (Swan mold) 38's and it was a disaster. These boats were built around the same time. Somtimes the smaller boatbuilders cut the wrong corners! If your plans are complete I would like to have a copy of them. Could you post them on this site? Could you email them to me? Let me know! Thanks, Robert.
A little clarification
Hi All, That last post was kind of short so this one will clarify things. The keel to keel stub connection on any boat is the most important structural part of the boat. The stresses caused by the weight of the keel on the hull must be completely carried by the keel stub joint without the keel moving one iota. Once it starts to move, the party is over. Only the best boats have a solid fibreglass keel stub. It is time consuming to hand lay all that fibreglass and expensive. There are many options used. Catalina will tell you that plywood and balsa wood don't work. Once they rot, there is minimal strength left. Some builders pour in resin, some build in stringers and then use resin for the rest. Others now use special pressure processes which work very well. I recently inspected a keel stub connection which had been cut out of a racing sailboat. It was impressive. Eight inches of solid fibreglass supported by a grid system. Those keels are heavy and hang low. I have rebuilt a one-off Schock that used galvanized steel bolts and concrete. The boat has been sailing for 27 years without a problem. It is important to know how this part of the boat is built, and I doubt any of you will buy a sailboat again without the keel stub details. If any of you have a detail plan of the 37C, I sure would like to see it. Thanks, Robert.
Hi All, That last post was kind of short so this one will clarify things. The keel to keel stub connection on any boat is the most important structural part of the boat. The stresses caused by the weight of the keel on the hull must be completely carried by the keel stub joint without the keel moving one iota. Once it starts to move, the party is over. Only the best boats have a solid fibreglass keel stub. It is time consuming to hand lay all that fibreglass and expensive. There are many options used. Catalina will tell you that plywood and balsa wood don't work. Once they rot, there is minimal strength left. Some builders pour in resin, some build in stringers and then use resin for the rest. Others now use special pressure processes which work very well. I recently inspected a keel stub connection which had been cut out of a racing sailboat. It was impressive. Eight inches of solid fibreglass supported by a grid system. Those keels are heavy and hang low. I have rebuilt a one-off Schock that used galvanized steel bolts and concrete. The boat has been sailing for 27 years without a problem. It is important to know how this part of the boat is built, and I doubt any of you will buy a sailboat again without the keel stub details. If any of you have a detail plan of the 37C, I sure would like to see it. Thanks, Robert.
Drill and tap?
RC, What do you mean by drilling and taping into the top of the keel. You can't do that in a lead keel.
RC, What do you mean by drilling and taping into the top of the keel. You can't do that in a lead keel.
Hunter Cherubini Bolts
I purchased a Hunter Cherubini 25 1976 virtually out of the junk yard and set about restoring this hardy boat. The first thing I noticed was that there existed a 1/2" separation between the lead keel and the hull from the front of the keel to half way to the back. I asked a marina owner about it after looking at it he didn't seem too alarmed. So I set about correcting this problem. Inside the boat in the bilge were no less than 7 bolts 3 sets doubled and one in the front. I began tightening them most turned and shored up their space however the one front bolt and one of the front sets wouldn't tighten, the nuts kept on turning, a sure sign that they were stripped. At this point I had to choose whether to abandon the project altogether or remove the nuts by craking them. Because of the space and the size of the nuts including their makeup it was near to impossible to break them and replace them. I decided to add another nut and tighten as best as I could. I also added before tightening, 5200 and Marinetex in the open seam. After hauling this boat out at the end of this last successful season of sailing I half expected to find a keel with great stress damage to it, (even though I had no signs of leaking). My keel showed no signs of any stress at all, with a solid fiberglass construction particularly at that point, this boat has shown it's resilence and its "Phoenix" like qualities.
I purchased a Hunter Cherubini 25 1976 virtually out of the junk yard and set about restoring this hardy boat. The first thing I noticed was that there existed a 1/2" separation between the lead keel and the hull from the front of the keel to half way to the back. I asked a marina owner about it after looking at it he didn't seem too alarmed. So I set about correcting this problem. Inside the boat in the bilge were no less than 7 bolts 3 sets doubled and one in the front. I began tightening them most turned and shored up their space however the one front bolt and one of the front sets wouldn't tighten, the nuts kept on turning, a sure sign that they were stripped. At this point I had to choose whether to abandon the project altogether or remove the nuts by craking them. Because of the space and the size of the nuts including their makeup it was near to impossible to break them and replace them. I decided to add another nut and tighten as best as I could. I also added before tightening, 5200 and Marinetex in the open seam. After hauling this boat out at the end of this last successful season of sailing I half expected to find a keel with great stress damage to it, (even though I had no signs of leaking). My keel showed no signs of any stress at all, with a solid fiberglass construction particularly at that point, this boat has shown it's resilence and its "Phoenix" like qualities.
Kind of Like an Equivalent!
Hi Sine, Thank you for the reply. Sometimes it is easier to simplify things a bit than to get carried away with a long explanation. The "new thread" for a new keel bolt is actually a cylindrical piece of stock which has been machined and threaded. They are inserted from the side of the keel after the bolt holes have been bored. They can be any lenth you desire, but two inches of thread is usually enough. In the past we have carefully measured where to bore and chisel into the side of the keel, or dropped the keel after boring and precisely marked where the new holes are (a lot more work). The keel stub has to be is pretty bad shape to drop the keel. It may be possible to use an ultrasonic sounder to locate the holes, but lead is rather dense. This may or may not work. I haven't tried it. It really isn't too difficult to place the machined stock nuts if you are careful. Do you think the Cherubini keel stub is all fibreglass? When you tightened the nuts, did they "pull" into the top of the keel stub at all? Let me know, Robert.
Hi Sine, Thank you for the reply. Sometimes it is easier to simplify things a bit than to get carried away with a long explanation. The "new thread" for a new keel bolt is actually a cylindrical piece of stock which has been machined and threaded. They are inserted from the side of the keel after the bolt holes have been bored. They can be any lenth you desire, but two inches of thread is usually enough. In the past we have carefully measured where to bore and chisel into the side of the keel, or dropped the keel after boring and precisely marked where the new holes are (a lot more work). The keel stub has to be is pretty bad shape to drop the keel. It may be possible to use an ultrasonic sounder to locate the holes, but lead is rather dense. This may or may not work. I haven't tried it. It really isn't too difficult to place the machined stock nuts if you are careful. Do you think the Cherubini keel stub is all fibreglass? When you tightened the nuts, did they "pull" into the top of the keel stub at all? Let me know, Robert.
HCKB
No, the bolts I believe may have stripped some of the nuts approx. 3 with either years of wear or a hit to the keel. The surveyor didn't see any abuse to the boat. Bolts I believe as has been expressed previously are hooked so movement thereof is quite rare. But... I ain't no tech wiz with both the jargon and makeup of these crafts.
No, the bolts I believe may have stripped some of the nuts approx. 3 with either years of wear or a hit to the keel. The surveyor didn't see any abuse to the boat. Bolts I believe as has been expressed previously are hooked so movement thereof is quite rare. But... I ain't no tech wiz with both the jargon and makeup of these crafts.
My 37C keel.
The attached picture has a line drawn at the lead to fiberglass stub connection. I believe that the stub is solid glass. When I torque the 1 1/8" nuts the bolts do not move nor do the washers compress. But the washers are quite large. My '79 has never shown any signs of separation at the keel to hull joint. However this is a fresh water boat.
The attached picture has a line drawn at the lead to fiberglass stub connection. I believe that the stub is solid glass. When I torque the 1 1/8" nuts the bolts do not move nor do the washers compress. But the washers are quite large. My '79 has never shown any signs of separation at the keel to hull joint. However this is a fresh water boat.
Nice Picture, Rudder Available?
Thanks for the picture. It is the first time I have seen the C37 keel. Do you have a shot of the rudder as well? I have seen rudders on these in two forms, one with a short detached skeg, and another with a full length skeg. A picture or two would be helpful. There are two things noticeable about this picture, first, the keel is longer than usual, and second, there is quite a bit of hull below the waterline. Both are good. This brings us to another question. I have noticed the club staysail has "pushed" the mast back farther than usual. Do you have enough rudder to hold your course when close hauled with the rail in the water? Or does the boat turn into the wind on it's own? This is a huge question, and be sure I'll read any and all responses I get. Thanks, Robert.
Thanks for the picture. It is the first time I have seen the C37 keel. Do you have a shot of the rudder as well? I have seen rudders on these in two forms, one with a short detached skeg, and another with a full length skeg. A picture or two would be helpful. There are two things noticeable about this picture, first, the keel is longer than usual, and second, there is quite a bit of hull below the waterline. Both are good. This brings us to another question. I have noticed the club staysail has "pushed" the mast back farther than usual. Do you have enough rudder to hold your course when close hauled with the rail in the water? Or does the boat turn into the wind on it's own? This is a huge question, and be sure I'll read any and all responses I get. Thanks, Robert.
pictures
i have pictures of the last haul out and if you send me your address i will email direct as the files are to large to publish here
i have pictures of the last haul out and if you send me your address i will email direct as the files are to large to publish here
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