Chuck, I think you'll find that the "R" version will have plywood where the "+" and "XL" versions do not. It seems as the "R" were the first built and were built in fewer numbers (25 or so 37R vs. 100 or so 37+ & XL) and used more straight flat plywood interior pieces giving a stiffer, lighter hull. The + and XL had floors and "spider" (interior grid) made up on a mould and fitted and bonded into the hull.
Ken H. On 3 March 2014 23:09, Chuck S <[email protected]> wrote: > Jean-Francois, > Not sure where you got the research info? > > I've got hull number 2 in the 34/36 series and I am holding a 4" circle of > the deck I cut out for a solar fan and I find the balsa is 3/4" thick and > the rest of your layup list is probably right. As I look at the edge and > count the layers of glass and Kevlar, I see the outer layer is thicker than > the inside layer. > > Another thing I see is they tapered the edges of the balsa to where the > hull is solid. Some areas of the hull are solid laminate from the > hull/deck flange down to about 4" from the sheerline. The deck is solid > laminate about 4" in from the outer edge making a waterway, and all > vertical panels in the cockpit sides and along the cabin sides where the > windows are, have no balsa. I was surprised to find the transom is solid > laminate. But most horizontal surfaces have balsa coring for stiffening. > Including the spray hood that covers the companionway slide which has 3/8" > balsa coring, while the forward slanted surface and vertical sides of it > are solid. > > The floors on our boat (what the floorboards sit on) are built of two or > three layers of 3/4" marine grade plywood and are covered in at least 13 > alternating layers of glass and kevlar which become about 1/4" of solid > laminate over the wooden beams. (I had to repair some damage and counted > the layers before duplicating the original.) It's important that all > edges are well rounded and inner angles are filleted. A boat builder told > me the wood was really just a mold and the laminate provides the strength > and stiffens the hull. > > You sound as passionate about your 34+ as I am about my R. > > Chuck > Resolute > 1990 C&C 34R > Atlantic City, NJ > ------------------------------ > *From: *"Jean-Francois J Rivard" <[email protected]> > *To: *[email protected] > *Sent: *Monday, March 3, 2014 8:34:22 PM > *Subject: *Stus-List Understanding Composites > > So the Kevlar in the 34+ series and 37+ a well was not 'straight' Kevlar > but a hybrid and E-glass I guess this way you'd get the lightweight > resiliency of Kevlar with the stiffness of the glass: > > DuPont Aramat C72K/200 seems to have been an E-glass/Kevlar hybrid weave. > (From research on the web): > > Composition of the glass/Kevlar hybrid, DuPont's Aramat 72K/200: > > Component G/SQ.M OZ/SQ.YD Wt. % in Base Fabric Wt. % > inTotal Fabric > Glass Fiber 245.6 7.2 63 > 41.1 > Kevlar 49 144.0 4.2 37 > 24.0 > Mat Backing 200.0 5.9 -- > 33.5 > Stitching Yarn 8.0 0.2 -- > 1.4 > Total 597.6 17.5 > > > Also, in keeping with the stiffness / resiliency theme, the grid area on > those boats is a combo of the aforementioned Kevlar hybrid along with the > keel / mast step area containing Epoxy resin and Nomex (Also Kevlar based) > Honeycomb mat which was known for high cost but high strength / stiffness > with low weight and came from the Aerospace industry > > Here's the lay-up schedule: > > Topsides (total thickness 1.19") > 1. Gelcoat > 2. 1.5 oz. Chop > 3. 1.5 oz. Mat > 4. C72K/100 Kevlar Fabmat > 5. 1" Balsa Core > 6. C72K/100 Kevlar Fabmat > > Bottom (total thickness 1.23") > 1. Gelcoat > 2. 1.5 oz. Chop > 3. 1.5 oz. Mat > 4. C77K/200 Kevlar Fabmat > 5. 1" Balsa Core > 6. C72K/100 Kevlar Fabmat > > To avoid the potential issues with the balsa core on the factory mounted > through hulls, the through hull areas are devoid of balsa core made of > solid composite kevlar / Hydrex isophatlic resin (A type of Vinylester). > The isophtalic resin cures from the inside out and is very water resistant > (Read blister resistant) > > So what does all that mean? No Blisters, (My boat has one about half the > size a pencil eraser) No chalking, very stiff: all bulkhead doors open and > close like a safe, less weight means it can carry more ballast in the keel > and handle a pretty high power to weigh ratio (Around 12,500 lbs for 795 SQ > ft using the 135 gib, 96 base phrf) while having a fully teak lined cabin, > almost king sized bed in the aft cabin, separate shower with stand--room. / > shower curtain, and all the cruising amenities.. > > -Francois > 1990 C&C34+ "Take Five" > Lake Lanier, Georgia > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > [email protected] > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > [email protected] > >
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