I'm looking at a C-Dory 22 that has some damage to the back end of the keel. It looks like when it was put on or off the trailer the keel may have scraped on concrete - the gelcoat is removed completely for about 2' and the mat is roughed up, as if someone had gone over it with a rasp. I'm not concerned about the cosmetics of this, it's easily repaired. But I am aware that the 22's have a balsa-cored hull. The question is, does the coring extend down into the keel itself; or is the keel solid fiberglass; or is it filled with something else like plywood or solid wood? My concern is whether water could have entered at the bottom of the keel and made its way up into the balsa coring of the surrounding hull.
What's in the keel?
- Thread starter rsudama
- Start date
I have never taken the keel of a 22 apart to know for sure, but I would think there would not be any coring in the keel. I say this based on how coring is typically done. With balsa core (which is what I believe was used in 1987-newer 22's, it typically comes in big sheets. The sheets are scored into small blocks (say 3" x 3") but they are all held together with a scrim. This is so the sheet can bend in complex curves. So you'd have a female hull mold, and I would think it would be built up with (after the gelcoat) resin and fiberglass to make the outer skin (this seems to me like it would include the tiny keel stub). Then once you had a flat outer skin, you'd lay in the coring sheet. Then perhaps some filler (depends) and then the top fiberglass/resin skin.
Besides the form factor (sheets) of typical coring, other reasons:
1) I can't see why they would go to the extra trouble to cut little pieces of core and put them in the keel stub. That's extra work/time for no particular reason. It's hard enough to make money in the boat building biz.
2) Core is generally used to make large flat surfaces more rigid. This is one reason why the C-Dory doesn't have to have big frames or stringers (although it does have the fake strakes, but those are more in the topsides). Decks on fiberglass sailboats are often cored for the same reason. But smaller areas - especially if they have inherent curves - are often not cored - they are plenty strong on their own due to their shape. So there'd be no need for core in the keel stub.
Of course production boat builders of all sorts have been known to do things that don't make sense, or cause eventual problems --- but not usually if it would cause them extra work and time.
I'll be interested to see if anyone knows for sure. I could very well be wrong and the keel stub is cored. I'm just guessing based on what I know and past experience (other boats; haven't take the keel apart in my 22)
One way you might find out: Many folks have posted photos of their boats in the mold when they were being built. You might be able to see. (But searching the photos is not all that easy.)
PS: But looky here, an album with photos of the 22's being built - nifty:
http://www.c-brats.com/modules.php?set_ ... _album.php
Here is one photo (although of course processes can change over the years) showing the core lying in the hull. You can see it is one continuous sheet of balsa. Can't see under it but as mentioned above, I doubt they were taking little pieces of balsa and stuffing them into the tiny keel (not that it wasn't a good question on your part).
PPS: On the other hand, there could potentially be a void in the keel space, and there could potentially be a gap in the glass that would allow moisture into the core. So as always, I'd say best to repair damage ASAP and also to check for moisture in the hull (as I would do on any cored boat).
Besides the form factor (sheets) of typical coring, other reasons:
1) I can't see why they would go to the extra trouble to cut little pieces of core and put them in the keel stub. That's extra work/time for no particular reason. It's hard enough to make money in the boat building biz.
2) Core is generally used to make large flat surfaces more rigid. This is one reason why the C-Dory doesn't have to have big frames or stringers (although it does have the fake strakes, but those are more in the topsides). Decks on fiberglass sailboats are often cored for the same reason. But smaller areas - especially if they have inherent curves - are often not cored - they are plenty strong on their own due to their shape. So there'd be no need for core in the keel stub.
Of course production boat builders of all sorts have been known to do things that don't make sense, or cause eventual problems --- but not usually if it would cause them extra work and time.
I'll be interested to see if anyone knows for sure. I could very well be wrong and the keel stub is cored. I'm just guessing based on what I know and past experience (other boats; haven't take the keel apart in my 22)
One way you might find out: Many folks have posted photos of their boats in the mold when they were being built. You might be able to see. (But searching the photos is not all that easy.)
PS: But looky here, an album with photos of the 22's being built - nifty:
http://www.c-brats.com/modules.php?set_ ... _album.php
Here is one photo (although of course processes can change over the years) showing the core lying in the hull. You can see it is one continuous sheet of balsa. Can't see under it but as mentioned above, I doubt they were taking little pieces of balsa and stuffing them into the tiny keel (not that it wasn't a good question on your part).
PPS: On the other hand, there could potentially be a void in the keel space, and there could potentially be a gap in the glass that would allow moisture into the core. So as always, I'd say best to repair damage ASAP and also to check for moisture in the hull (as I would do on any cored boat).
Yes, that all makes sense. Unfortunately, the bottom is painted with anti-fouling, which very commonly disrupts the function of moisture meters used for testing for water intrusion. And because of the cockpit liner it is not easily accessible from inside the hull. So as far as I can see the only way to be sure water didn't get into the core through the keel would be to take core samples in the area, or at least punch some holes in the hull and see if anything drains out ("destructive" testing).
To your point about whether the keel might be hollow, that is certainly a possibility, although it seems like they would have filled this with glass as it is a somewhat vulnerable part of the boat. I suppose I could ask the C-Dory factory how this is done currently.
To your point about whether the keel might be hollow, that is certainly a possibility, although it seems like they would have filled this with glass as it is a somewhat vulnerable part of the boat. I suppose I could ask the C-Dory factory how this is done currently.
I didn't realize you were speaking of one of the 22's with the molded cockpit liner ("permanent" flat sole). (Those came in around 2007 or so, I believe.) That does complicate it slightly as you can't check from above, and bottom paint can somewhat obscure things from below.
I'd agree that it's likely the "keel" is filled solid. I only brought up the possibility of a void to explain why I'd want to repair any issue and/or check into it as much as possible vs. just leaving it.
I did have a pair of C-Dory floorboards (these were optional flat fiberglass floorboards you could lay in the cockpit of the pre-cockpit-liner boats - which other wise just have the inside of the hull as the cockpit "sole") that had small areas of damage turn large due to long voids between sections of core that allowed a small amount of water to have "the run of the place" and damage huge areas of their coring. However it's likely they took more care with the actual hull than with a small accessory such as a floorboard.
Can you poke something into this damaged area? I don't mean destructively, but say you took a wire and fished upwards to see if the damage is just a shallow scrape, or potentially leads to a void. My guess is it won't lead to anything and all will be fine; but think how much better you'd feel knowing for sure.
While I have heard of core damage in various places (due to the usual suspects on all cored boats such as through hulls, deck penetrations, etc.), I haven't heard of anyone having hull core damage due to keel scrapes (and I'm sure many of us have had those). Not that anyone would run aground, mind you :smile but our boats do get beached quite a bit (on purpose).
Glad to have you here and looking forward to hearing about your "new" C-Dory (whether it be this one or another one) :thup You are in a beautiful boating area!
I'd agree that it's likely the "keel" is filled solid. I only brought up the possibility of a void to explain why I'd want to repair any issue and/or check into it as much as possible vs. just leaving it.
I did have a pair of C-Dory floorboards (these were optional flat fiberglass floorboards you could lay in the cockpit of the pre-cockpit-liner boats - which other wise just have the inside of the hull as the cockpit "sole") that had small areas of damage turn large due to long voids between sections of core that allowed a small amount of water to have "the run of the place" and damage huge areas of their coring. However it's likely they took more care with the actual hull than with a small accessory such as a floorboard.
Can you poke something into this damaged area? I don't mean destructively, but say you took a wire and fished upwards to see if the damage is just a shallow scrape, or potentially leads to a void. My guess is it won't lead to anything and all will be fine; but think how much better you'd feel knowing for sure.
While I have heard of core damage in various places (due to the usual suspects on all cored boats such as through hulls, deck penetrations, etc.), I haven't heard of anyone having hull core damage due to keel scrapes (and I'm sure many of us have had those). Not that anyone would run aground, mind you :smile but our boats do get beached quite a bit (on purpose).
Glad to have you here and looking forward to hearing about your "new" C-Dory (whether it be this one or another one) :thup You are in a beautiful boating area!
This 22 is a 2000, and I actually haven't seen the cockpit myself. The surveyor said that it had a flat sole that was molded in and not removable. It's possible that's not the case, if so some things could be checked from the interior.
I'm inclined to agree with you that this may not be a serious issue, I'm just looking for other educated opinions, especially from owners who may have some direct experience with keel damage of this nature. In other respects the boat appears pretty sound and has other features that I've been looking for.
I'm inclined to agree with you that this may not be a serious issue, I'm just looking for other educated opinions, especially from owners who may have some direct experience with keel damage of this nature. In other respects the boat appears pretty sound and has other features that I've been looking for.
It's possible that the 2000 22 has a custom later add in of the cockpit liner that was added in around 2007-present. For example, Triton offered one to me (for purchase) when I was there buying some other parts in 2012 (I prefer mine the way it is though for various reasons). Or a previous owner could have made some sort of cockpit sole (that would typically be removeable, but who knows).
The way the 2000 boats came, the cockpit "sole" was simply the top skin of the hull, and so followed the shape of the hull (literally you'd be standing on "the top of the bottom" of the boat). At some point (not sure when), they started offering optional molded floorboards that made the cockpit sole flat. These were a pair with a split down the middle (hence removable). They were molded and gelcoated to match the boat, with matching non-skid. They don't look built in to my eye, but maybe if something were over them, or a person was glossing over a bit....?
So, unless someone put in a permanent sole (which would be unusual as there are drainage issues to overcome), or they went to Washington and had a new-style cockpit liner put in after 2007 or so, whatever is there making the sole flat on a 2000 model should be liftable and you should be able to get to the top skin of the hull (and hence check for moisture in the core).
(I have a 2002, which is very similar to a 2000.)
The way the 2000 boats came, the cockpit "sole" was simply the top skin of the hull, and so followed the shape of the hull (literally you'd be standing on "the top of the bottom" of the boat). At some point (not sure when), they started offering optional molded floorboards that made the cockpit sole flat. These were a pair with a split down the middle (hence removable). They were molded and gelcoated to match the boat, with matching non-skid. They don't look built in to my eye, but maybe if something were over them, or a person was glossing over a bit....?
So, unless someone put in a permanent sole (which would be unusual as there are drainage issues to overcome), or they went to Washington and had a new-style cockpit liner put in after 2007 or so, whatever is there making the sole flat on a 2000 model should be liftable and you should be able to get to the top skin of the hull (and hence check for moisture in the core).
(I have a 2002, which is very similar to a 2000.)
The 2000 would have the inner side of the hull as the bottom of the cockpit and cabin floor. Unless there was some very unusual and serious modification of the boat. Get a photo of the cockpit floor. (If possible examine the boat yourself--often a surveyor's idea and your idea may not be the same).
I hate to say it, but all surveyors are not equal...Be sure this guy knows what he is talking about....
The removable floor option did not come along until about 2004?==but it could have been put in earlier boats easily. It is possible, but unlikely, that someone would put a removable floor on and glass it in--bad idea, and I would reject that boat. All kinds of material can collect under the "removable" floor. Even some of the factory flat solid floors have had problems with water getting into this area.
The keel is not cored. AS HomerJack suggested, this is an easy repair. Should be no core damage, or water intrusion.
I hate to say it, but all surveyors are not equal...Be sure this guy knows what he is talking about....
The removable floor option did not come along until about 2004?==but it could have been put in earlier boats easily. It is possible, but unlikely, that someone would put a removable floor on and glass it in--bad idea, and I would reject that boat. All kinds of material can collect under the "removable" floor. Even some of the factory flat solid floors have had problems with water getting into this area.
The keel is not cored. AS HomerJack suggested, this is an easy repair. Should be no core damage, or water intrusion.
If this happens to be the '2000' for sale on CL in Tacoma, there is no cockpit liner, and the bottom paint did not interfere with moisture meter measurements taken from inside. But I didn't get as far as crawling underneath to notice any keel damage. Agreed, the keel should be solid fill, at least the one on my 1990 16 was, as observed when replacing my floor.
-Mike
-Mike
AstoriaDave
New member
One to four milled glass fibers / Cabosil aka fumed silica, mixed to make a thick paste similar to peanut butter with epoxy. Trowel it on, smooth with squeegee, at partial cure sculpt with scraper, sand when cured. System Three and WEST bothnsell these fillers. The milled glass is for strength, the Cabosil for thickener. No more goop in the face.homerjack":2baeof3v said:
Dave, You do make it sound easy. Now it's just getting under the boat, and crawling around down there and then getting back out and up again :wink: :roll: :shock: :twisted:
How long would you have before that mix "goes off" and you are not able to work it anymore? Do the thickening agents have any affect on the hardening time?
Harvey
SleepyC :moon
How long would you have before that mix "goes off" and you are not able to work it anymore? Do the thickening agents have any affect on the hardening time?
Harvey
SleepyC :moon
Harvey,
I don't find much difference in the pot life with thickeners. I choose the hardener based on temperature/pot life time wanted. Generally 20 to 30 minutes pot life. Mix the epoxy before adding milled fibers/cabosil/ and high density filler. Unfortunately I have also had a fair amount of experience putting glass on bottoms--both in blister repair, and in hull/rudder/skeg and keel modifications. It is not too bad if you don't overly wet the glass. I personally prefer epoxy for these type of repairs.
Where folks can get in trouble is taking too long to get the right amount of milled fibers and carbonyl/high density filler. They keep adding in little amounts and staring. You need to add almost enough right off, and then adjust with one or two more additions...It takes more filler than one might expect.
I don't find much difference in the pot life with thickeners. I choose the hardener based on temperature/pot life time wanted. Generally 20 to 30 minutes pot life. Mix the epoxy before adding milled fibers/cabosil/ and high density filler. Unfortunately I have also had a fair amount of experience putting glass on bottoms--both in blister repair, and in hull/rudder/skeg and keel modifications. It is not too bad if you don't overly wet the glass. I personally prefer epoxy for these type of repairs.
Where folks can get in trouble is taking too long to get the right amount of milled fibers and carbonyl/high density filler. They keep adding in little amounts and staring. You need to add almost enough right off, and then adjust with one or two more additions...It takes more filler than one might expect.
And in your typically cool PNW climate, if you want a loooong working time, use the slow hardener. I've done that a time or two (when I needed a long working time and/or was out of faster hardener) and trust me, you have plenty of working time. I was wishing it would just go ahead and cure so I could get on with things!
If you have to lay glass above you (actual cloth that is), then if you "paint on" the first layer of neat epoxy and let it tack up (then mix more resin later for wetting out the cloth), that tacky coat will "grip" the cloth somewhat. It will still be in the green stage, so chemical bond.
I've also used bits of blue tape to help hold things up as they cure. Or if it's a flat surface, a board or etc. covered in packing tape (releases easily).
Still haven't found a way to make the sanding dust fall "up" though
A vacuum hose on a stick (so you can keep it right at the work area) helps a lot.
If you have to lay glass above you (actual cloth that is), then if you "paint on" the first layer of neat epoxy and let it tack up (then mix more resin later for wetting out the cloth), that tacky coat will "grip" the cloth somewhat. It will still be in the green stage, so chemical bond.
I've also used bits of blue tape to help hold things up as they cure. Or if it's a flat surface, a board or etc. covered in packing tape (releases easily).
Still haven't found a way to make the sanding dust fall "up" though
A vacuum hose on a stick (so you can keep it right at the work area) helps a lot.AstoriaDave
New member
Ugh. Know that feeling. Someone already answered on how thickeners affect pot life: they don't, EXCEPT having to mix in milled glass fibers and thickener chews up so much pot time that it seems like thickeners shorten it. As Sunbeam says, use slow hardener if you got it.hardee":nceiq0gs said:Dave, You do make it sound easy. Now it's just getting under the boat, and crawling around down there and then getting back out and up again :wink: :roll: :shock: :twisted: How long would you have before that mix "goes off" and you are not able to work it anymore? Do the thickening agents have any affect on the hardening time?
Harvey
SleepyC :moon
The other trick is to measure (e.g., WEIGH OUT) your resin and hardener onto a square of Formica or similar, using a squeegee edge to mix it up, and then add milled glass and thickener to it, mixing further until you are there. Weighing by pouring each part directly onto adjacent areas on the Formica hastens the process and minimizes the waste involved in using measuring containers. If the job is big enough to use the pumps, then that is faster.
The prime advantage of using a surface for mixing etc., is that the mix has a lot more surface area than it does in a cup or yogurt container, and dissipates the hest produced during curing ... extending pot life a lot.
More tricks in the literature from either System Three or WEST. Both are excellent, but have their corps of devotees.
To follow up with some information, I did purchase this boat and have done some initial repair to the keel (yes, I did crawl under the boat, and even in the rain). I scraped away as much of the exposed mat as needed down to solid glass and determined that the keel is NOT solid, it appears to have some kind of coring, but not balsa. This seemed like a charcoal grey slab as near as I could tel, almost like a strip of carbon fiber.
In any case, I did NOT try to use epoxy with filler as described, because I have too much experience with that sagging no matter how stiff you make it, and I don't relish having a faceful of the stuff (or of having to shore up the repair to keep the keel flat). I used Marine Tex, an epoxy putty, which as I suspected was much stiffer and stickier. I was able to force it up into the area I had cleaned out as well as shape it and smooth it off fairly well flush with the bottom of the keel. At some point I'll sand this whole area down to the glass and apply some tape to further protect it.
Thanks for all the info on this, it was very helpful.
In any case, I did NOT try to use epoxy with filler as described, because I have too much experience with that sagging no matter how stiff you make it, and I don't relish having a faceful of the stuff (or of having to shore up the repair to keep the keel flat). I used Marine Tex, an epoxy putty, which as I suspected was much stiffer and stickier. I was able to force it up into the area I had cleaned out as well as shape it and smooth it off fairly well flush with the bottom of the keel. At some point I'll sand this whole area down to the glass and apply some tape to further protect it.
Thanks for all the info on this, it was very helpful.
I think that was a controversial mod made during the Tom Latham era of the ark factory. Earlier ark owners commented that they much preferred the wood elephant stalls as they were easier to work on with normal carpentry tools while later owners appreciated the ease of clean-up.hardee":15sx47bg said:Just the parts under the elephant stalls. :wink:
Harvey
SleepyC :moon
