This may be a re-hash of old news, but I found MikePorterinMD's (Shelly-IV) cutaway section photos to be absolutely fascinating. Not sure how he came up with the sections. These photos confirm to me at least 2 critical points: 1. The strength of the CD22 is absolutely dependent on the quality of layup and construction, and 2. It is vital that all core penetrations be properly sealed and kept to a minimum. I knew our boats' strength came more from design than from being overbuilt, but seeing these images hammers it home. Thanks to Mike for the useful information. Mike.
CD 22 Cutaway Photos
- Thread starter westward
- Start date
mikeporterinmd
New member
You're welcome! They were taken at Cutter Marine. Now that Cutter no longer sells C-Dory, I'm really glad I took those when I did!
If anyone wants them, I have high resolution versions I can email.
Yup, the boat is built as one solid piece. Kinda prefer it over the traditional stringer system. Particularly after what happened to the Searay. (Searay didn't seal a hole and a stringer rotted.)
Mike
If anyone wants them, I have high resolution versions I can email.
Yup, the boat is built as one solid piece. Kinda prefer it over the traditional stringer system. Particularly after what happened to the Searay. (Searay didn't seal a hole and a stringer rotted.)
Mike
Christopher-Robyn
New member
Mike:
I would really appreciate a set of the high resolution cutaway photos! They will come in handy as a reference before making any future repairs or mods. Thanks!
Paul K
I would really appreciate a set of the high resolution cutaway photos! They will come in handy as a reference before making any future repairs or mods. Thanks!
Paul K
Captains Cat
New member
Warren, at least on a 22, they can learn where the core is and where it isn't! About how thick things are, before they cut and where/how to mount stuff to the hull.
It's probably the same technique on all their hulls but it would be nice to see other models. Anyone want to offer to cut their boats up to show us? :shock:
Not me...
Charlie
It's probably the same technique on all their hulls but it would be nice to see other models. Anyone want to offer to cut their boats up to show us? :shock:
Not me...
Charlie
Christopher-Robyn
New member
Mike:
Still waiting to receive the high resolution cut-away photos you offered! Any problems?
Paul K
Still waiting to receive the high resolution cut-away photos you offered! Any problems?
Paul K
Rob & Karen
New member
Mike,
I would like to receive a set of the high resolution photos as well. Thanks.
Rob
I would like to receive a set of the high resolution photos as well. Thanks.
Rob
marvin4239
New member
Doryman":vfzh0k94 said:
I saw a cut out of the roof of a 25 at Wefing that they were installing and AC on and it appeared to be the same as the roof of the cutout. Cored but not the same thickness as the bottom. Don't have a clue about the rest of a 25 but I would think it would be the same construction technique.
Various models have at least different roof core structure. I belive that this 22 has no core in the center of the roof. Our Tom Cat has about a 1" core in the center of the roof--but no core (could have thin coremat) in the outer parts of the roof. On the other hand, our CD 25 has no core in the center of the roof--and seems to have core on the side parts of the roof.
The aft bulkhead on the Tom Cat is cored, as is the wall of the head on inboard and foreward bulkheads.
The aft bulkhead on the Tom Cat is cored, as is the wall of the head on inboard and foreward bulkheads.
mikeporterinmd
New member
Christopher-Robyn":2xcs9h36 said:
I have a number of emails from folks, but I'm away for a few days. If I have the photos on this computer, I will email them out. If not, I will send them out Monday or Tuesday.
Perhaps they can be uploaded to the tech docs section of the site?
Mike
mikeporterinmd
New member
When you drill through the roof where I have my antennas mounted, it feels like there is a core in there...about 1/4" or so. I don't know if it is balsa or something else.
Mike
Mike
Mike,
The thinnest balsa core is 1/4", there are some foams which are thinner (1/8"), and there is a material called "Core Mat" which has microballoons with random mat fibers (2 and 4 mm thick), which is also used as a filler.
It is often hard to determine the composition when just drilling a small hole. But if a hole saw is used and a section is removed (like for pulling a radar cable) then you can see how thick and what the composition of the core material is.
The thinnest balsa core is 1/4", there are some foams which are thinner (1/8"), and there is a material called "Core Mat" which has microballoons with random mat fibers (2 and 4 mm thick), which is also used as a filler.
It is often hard to determine the composition when just drilling a small hole. But if a hole saw is used and a section is removed (like for pulling a radar cable) then you can see how thick and what the composition of the core material is.
marvin4239
New member
The section I saw cut out of the roof of the 25 at Wefings appeared to be balsa and the core was about 3/8 inch thick.
mikeporterinmd
New member
Hi,
Until the photos can be loaded to c-brats, they are available at
http://udel.edu/~mike/cd22-cutaway/
Mike
Until the photos can be loaded to c-brats, they are available at
http://udel.edu/~mike/cd22-cutaway/
Mike
mikeporterinmd
New member
Nope. I took those the day I bought my CD-22 and was never back to Cutter. Didn't think to ask that day. Now they are no longer a dealer, so I suppose the hull isn't there any more.
Maybe someone that lives closer or keeps a boat there can ask?
Mike
Maybe someone that lives closer or keeps a boat there can ask?
Mike
If you zoom in on the port side shot there appears to be an excerpt from a trade article/advertisement attached to the boat section, under a plexiglass cover. I couldn't read the whole thing but it's from the Baltek corp. (mfg. of the core materials), so I'm thinking they may have sponsored the dissection of this obviously used hull for promotional purposes. Go to their website and dig around. You can find their instructions for laminating with balsa core. These instructions indicate that a fair amount of technical skill and quality control is required for balsa core to be used successfully in a hull. for example they warn against air voids between the balsa and the FRP, and give specific instructions for wetting the balsa to avoid resin starvation (and presumably delamination). It is easy to imagine QC problems in boats built using these materials if great care is not taken in the layup process. Mike.
Very interesting.
I got an education in laminate hull construction this week. We had a presentation by Dan Newland, owner of Pegasus XIV, a 37 foot fin keel sloop that is built extremely light, of carbon fiber. The whole boat is 6000#. Combined deck and hull are only 1050#! Total hull width was about an inch with foam or balsa inside, and the skins only about as thick as your thumbnail. A square foot of hull weighs 1.5#.
He and/or his wife have won the Transpac Race 5 out of 7 times entered, as well as most other races they are in, some singlehanded, some crewed. He has seen top speeds just over 30 KTS! I didn't know a single hull sailboat could do that.
The boat will be based in Port Townsend starting this summer.
Dave
I got an education in laminate hull construction this week. We had a presentation by Dan Newland, owner of Pegasus XIV, a 37 foot fin keel sloop that is built extremely light, of carbon fiber. The whole boat is 6000#. Combined deck and hull are only 1050#! Total hull width was about an inch with foam or balsa inside, and the skins only about as thick as your thumbnail. A square foot of hull weighs 1.5#.
He and/or his wife have won the Transpac Race 5 out of 7 times entered, as well as most other races they are in, some singlehanded, some crewed. He has seen top speeds just over 30 KTS! I didn't know a single hull sailboat could do that.
The boat will be based in Port Townsend starting this summer.
Dave