randii 91 Posted March 3, 2020 Share Posted March 3, 2020 James did a post-mortem walk-through that was really interesting: This is a follow-up to the original 'wrecked' video: Quote Link to post Share on other sites
randii 91 Posted March 3, 2020 Author Share Posted March 3, 2020 As an owner of an epoxy-composite catamaran, I have more than passing interest in other... er... well... plywood boats (mincing words for best insurability). I'm not interested in a trip to Hawaii, my tastes run more to coastal cruising, but it was still interesting to see the post-mortem walk-through. I was pleased to see that much of the wood was in great condition... and that there were some out-of-plan cuts and bolts that focused loading. Seems like Zingaro held herself together well, for the most part, but her miles eventually caught up with her in heavy usage. Quote Link to post Share on other sites
toolbar 32 Posted March 3, 2020 Share Posted March 3, 2020 Very interesting (and scary) video. Paul Quote Link to post Share on other sites
boardhead 213 Posted March 3, 2020 Share Posted March 3, 2020 Still thinking wood is perfect for building trees! Quote Link to post Share on other sites
Rasputin22 2,722 Posted March 3, 2020 Share Posted March 3, 2020 Boat was a veritable Petri dish! 2 Quote Link to post Share on other sites
boardhead 213 Posted March 3, 2020 Share Posted March 3, 2020 That’s what happens when you soak dead wood in water for a while! Quote Link to post Share on other sites
KC375 1,688 Posted March 4, 2020 Share Posted March 4, 2020 6 hours ago, Rasputin22 said: Boat was a veritable Petri dish! 3 hours ago, boardhead said: That’s what happens when you soak dead wood in water for a while! It seemed there may have been a design issue and some ill conceived modifications / weakening of the structure BUT the biggest failure was glue failure rather than wood fiber failing. Was the wrong glue used/wrong grade of plywood? I’ve always had a soft spot for plywood boats...I’m now thinking that soft spot must be between my ears. Quote Link to post Share on other sites
DtM 561 Posted March 4, 2020 Share Posted March 4, 2020 It had lasted a long time (and a lot of miles) before it finally failed. Maybe there should have been more ongoing maintenance. Quote Link to post Share on other sites
Mitre cut 68 Posted March 4, 2020 Share Posted March 4, 2020 it must have been a damp boat inside looking at all the mould. The moisture content of the timber was also possibly very high leading to glue bonding failures in multiple places. I would like to see where the chainplates are so we can consider the rig forces involved and the bending loads on the hulls leading to the failure. Quote Link to post Share on other sites
Russell Brown 806 Posted March 4, 2020 Share Posted March 4, 2020 10 hours ago, boardhead said: Still thinking wood is perfect for building trees! Yep, and I still think it's perfect for building boats. Wood boatbuilding technology has improved just as fast as any other boat building material. I trust the stuff more than anything else, so stick it! 5 Quote Link to post Share on other sites
MRS OCTOPUS 140 Posted March 4, 2020 Share Posted March 4, 2020 5 hours ago, Mitre cut said: it must have been a damp boat inside looking at all the mould. The moisture content of the timber was also possibly very high leading to glue bonding failures in multiple places. I would like to see where the chainplates are so we can consider the rig forces involved and the bending loads on the hulls leading to the failure. The vessel is rigged with inline spreaders. Chainplates are bolted to packers on main beam just outboard of the bridgedeck cuddy cabin sides, well inside of extreme beam. The chainplate bolts are visible well inboard of cracked area at 18:05 aprox. on walk through video posted above. ( just behind sail lying on bunk). That looks one nasty, modified, poorly maintained boat . The bulk head cut outs (door ways) look like they have been enlarged a little over the boats life to make liveability a little easier, and the only tools at hand for the job was an axe. I'm surprised it lasted so long. I suspect it was cheap. For good reason. 1 Quote Link to post Share on other sites
randii 91 Posted March 4, 2020 Author Share Posted March 4, 2020 They got a pretty good number of sea miles out of her, and she delivered them to Hawaii alive... albeit stressed. Sure, there are lessons to learn, but they are out there cruising... that ain't bad. 1 Quote Link to post Share on other sites
smj 2 Posted March 4, 2020 Share Posted March 4, 2020 We looked at purchasing Zingaro about 5 years ago. Beautiful cat, well maintained but some things that put me of. The hulls are Airex and the rest of the boat was marine fir ply I believe. What I didn’t care for was the ply wasn’t encapsulated, had a layer of glass on one side and the other side was bare painted fir. Probably not a disaster for most parts of the boat except the bridgedeck. The bridgedeck was fir ply that was glassed on the inside and just painted on the bottom, fully exposed to the ocean. It appears from the video that the hull to bridgedeck tabbing has broken loose at the bridgedeck and pretty much remained intact on the hull. Just a theory, but if that tabbing released would it put undo stress on the beams possibly causing the damage they received? Quote Link to post Share on other sites
kruiter 9 Posted March 4, 2020 Share Posted March 4, 2020 It was on Craigslist Hawaii for $16K or something yesterday, but gone today. Wonder if it sold or they decided to put it out of its misery. Or maybe they decided to fix it? Quote Link to post Share on other sites
The Mad Hatter 63 Posted March 4, 2020 Share Posted March 4, 2020 17 hours ago, Russell Brown said: Yep, and I still think it's perfect for building boats. Wood boatbuilding technology has improved just as fast as any other boat building material. I trust the stuff more than anything else, so stick it! I think the major problem with wood boats is not the wood but the builder. A couple of simple rules have always worked for me. The wood has to be dry and when the resin is applied the wood needs to be cooling and not warming up unless applying a vacuum. All fixing holes need to be oversized and filled and then re drilled with a smaller drill to keep a healthy layer of thickened epoxy between the moisture and the wood. I also like putting a light layer of glass over it to stop the grain from opening up and letting moisture in on areas exposed to the elements. It is a very easy material to work with and for this reason may attract builders that just don't have the knowledge/experience to do it right. Don't blame the wood, blame the builder. Quote Link to post Share on other sites
Zonker 2,866 Posted March 4, 2020 Share Posted March 4, 2020 The bridgdeck to hull connection was very suspect. Just a light layer of taping, not very wide. And it was a 90 degree corner not a curve or chamfered panel. That's a pretty highly loaded connection area and it wouldn't surprise me that it started failing there. But the structural damage was so extensive it was clear that it didn't have a lot of structural redundancy either. And the post build cutouts/modifications were bad. As was the wet wood in key areas. They were lucky. 1 Quote Link to post Share on other sites
kruiter 9 Posted March 4, 2020 Share Posted March 4, 2020 Oops, here it is: https://honolulu.craigslist.org/mau/boa/d/lahaina-1984-crowther-spindrift-38/7076051671.html Quote Link to post Share on other sites
shaggy 826 Posted March 4, 2020 Share Posted March 4, 2020 Where is Squeeky?? I am sure they would be good for about 20 grand as is. Fly to Hawaii, fix her up, Florida here we come...... 1 Quote Link to post Share on other sites
Russell Brown 806 Posted March 5, 2020 Share Posted March 5, 2020 4 hours ago, The Mad Hatter said: I think the major problem with wood boats is not the wood but the builder. A couple of simple rules have always worked for me. The wood has to be dry and when the resin is applied the wood needs to be cooling and not warming up unless applying a vacuum. All fixing holes need to be oversized and filled and then re drilled with a smaller drill to keep a healthy layer of thickened epoxy between the moisture and the wood. I also like putting a light layer of glass over it to stop the grain from opening up and letting moisture in on areas exposed to the elements. It is a very easy material to work with and for this reason may attract builders that just don't have the knowledge/experience to do it right. Don't blame the wood, blame the builder. Thanks Hatter. You are more articulate and polite than I am. I have only built in wood/epoxy and composites, but at this point I'm really in love with plywood, lumber, and epoxy and really sick of composites. I have done most levels of composite work and I've grown to really dislike the materials and the waste generated. The only thing you failed to mention is the very forgiving nature of wood/epoxy from an engineering aspect. Things that shouldn't work can work. Under-engineered or under-built structures can be surprisingly strong and long lasting. I don't pretend to know everything, but I really like wood/epoxy boats. 4 Quote Link to post Share on other sites
OldmateFred 15 Posted March 5, 2020 Share Posted March 5, 2020 I've never heard of using expanding foam for a fillet before. Surely that has the sheer of toilet paper and that joint between hull and deck/bridge in the tunnel could not be considered load bearing, just used to keep water out and make it look good. All things considered though 40 years is pretty good and I'm sure it's seen some large waves and loads in it's time. Nothing lasts forever. Thankfully no-one was hurt or injured. Quote Link to post Share on other sites
boardhead 213 Posted March 5, 2020 Share Posted March 5, 2020 Spent the last couple days laminating the skins on a replacement composite daggerboard for a Newick Native and I agree that it’s pretty unpleasant work compared to replicating the glass sheathed wooden original that failed. The skin cracked and delaminated, the wood became waterlogged and degraded. The board was 39 years old. I love the smell of cedar which would have been a good choice for a new wooden board and have made many beautiful things out of wood and will continue to do so. The owner told me the original board weighed 180 pounds. The Native is a beauty but could benefit from losing a couple pounds, the composite board will be half the weight even though it’s two feet longer and ruggedly built. If your preference is for a wooden structure that’s great. For me the ability to orient filaments throughout these complex multihull structures to create light, strong, durable boats is intoxicating - in more ways than 2 hours ago, Russell Brown said: Thanks Hatter. You are more articulate and polite than I am. I have only built in wood/epoxy and composites, but at this point I'm really in love with plywood, lumber, and epoxy and really sick of composites. I have done most levels of composite work and I've grown to really dislike the materials and the waste generated. The only thing you failed to mention is the very forgiving nature of wood/epoxy from an engineering aspect. Things that shouldn't work can work. Under-engineered or under-built structures can be surprisingly strong and long lasting. I don't pretend to know everything, but I really like wood/epoxy boats. 2 Quote Link to post Share on other sites
randii 91 Posted March 5, 2020 Author Share Posted March 5, 2020 If someone was building a similar-size vessel, $15K ask (maybe $10K or less actual, storage and the owners moving on to a different boat will drive that price down) could be a good deal for newish sails and synthetic standing rigging, a coupla Yanmars, solar and batteries, head, autopilot, and other cruising gear. I can't see putting the Spindrift back together, but she would make a great donor. 3 Quote Link to post Share on other sites
rog2 2 Posted March 7, 2020 Share Posted March 7, 2020 The early Spindrifts were designed for the bottom chord of the main beam to finish inboard to allow for easy access. This is most likely the principal reason for the failure. As the video explains, the timber was overall pretty good so it was a structural, not material failure. Quote Link to post Share on other sites
kruiter 9 Posted March 9, 2020 Share Posted March 9, 2020 We have a pretty boisterous ocean out here in Hawaii anyway, and some of the channels are pretty horrifying, and this year has been much worse than usual. Last year, I was out most every week, but maybe once or twice this whole winter. Quote Link to post Share on other sites
PIL66 - XL2 920 Posted March 10, 2020 Share Posted March 10, 2020 Shame but it was old and now it's future is firewood...... You would not be fixing that boat Quote Link to post Share on other sites
rocnoggin 1 Posted April 4, 2020 Share Posted April 4, 2020 In a subsequent video James said the boat had been sold and it sounded like the new owners were indeed going to try to rebuild the boat. Quote Link to post Share on other sites
toolbar 32 Posted April 4, 2020 Share Posted April 4, 2020 Good luck to them. It's not like he didn't tell them about the boat's condition. Paul Quote Link to post Share on other sites
Russell Brown 806 Posted April 5, 2020 Share Posted April 5, 2020 One can rebuild just about anything. I have no idea if this boat is worth it, but sometimes the oldest, rattiest, and most cobbed together boats go the farthest and give the most back. Quote Link to post Share on other sites
Zonker 2,866 Posted April 5, 2020 Share Posted April 5, 2020 Did you look at the video he posted of the failure points. Whole boat just kind of gave up at the same time. I'm up for a rebuilding challenge but I would have run from that one. Quote Link to post Share on other sites
KC375 1,688 Posted April 5, 2020 Share Posted April 5, 2020 8 hours ago, Zonker said: Did you look at the video he posted of the failure points. Whole boat just kind of gave up at the same time. I'm up for a rebuilding challenge but I would have run from that one. Friedrich Nietzsche: "That which does not kill us makes us stronger." I think the challenge of rebuilding Zingaro will fall into the kill category...or the failure of the rebuild will later put you in that category. Quote Link to post Share on other sites
boardhead 213 Posted April 5, 2020 Share Posted April 5, 2020 Maybe the foam cored/glass lower hull structure could be used as a basis for the rebuild further justified by the (should be) super cheap, used parts bin that came with the deal. Redoing the deck/wing structure in glass/foam would be big $ relative to the wreck cost so maybe an open beam approach would prove worthwhile. Quote Link to post Share on other sites
Geese 37 Posted April 6, 2020 Share Posted April 6, 2020 On 4/4/2020 at 11:39 PM, Russell Brown said: One can rebuild just about anything. I have no idea if this boat is worth it, but sometimes the oldest, rattiest, and most cobbed together boats go the farthest and give the most back. Not that she is ratty, but I’ve developed a crush on this boat, that has been rebuilt many times.https://www.smyc.com/post/a-caribbean-treasure-the-trimaran-tryst-to-celebrate-50th-birthday-at-2019-caribbean-multihull-c I think there is one on Saint Croix that has an ok hull but needs a deck. You skippered her at one point, yeah? I wish my brother would rebuild her. He is out of work because of covid. Idleness down there can make one rum dumb pretty quick. 1 Quote Link to post Share on other sites
ProaSailor 414 Posted April 6, 2020 Share Posted April 6, 2020 26 minutes ago, Geese said: Not that she is ratty, but I’ve developed a crush on this boat, that has been rebuilt many times.https://www.smyc.com/post/a-caribbean-treasure-the-trimaran-tryst-to-celebrate-50th-birthday-at-2019-caribbean-multihull-c I think there is one on Saint Croix that has an ok hull but needs a deck. You skippered her at one point, yeah? I wish my brother would rebuild her. He is out of work because of covid. Idleness down there can make one rum dumb pretty quick. Aye, she's a beauty! Great story too. Clearly a lot of passion went into preserving this old wooden boat, esp. recovering from hurricanes Gonzalo (2014) and Irma (2017). A Caribbean Treasure, the Trimaran Tryst to Celebrate 50th Birthday at 2019 Caribbean Multihull Challenge By Herb McCormick, Dec 27, 2018 https://www.smyc.com/post/a-caribbean-treasure-the-trimaran-tryst-to-celebrate-50th-birthday-at-2019-caribbean-multihull-c Quote Her main hull and amas (outriggers) were built in Orlando, Maine of cold-molded mahogany at the Thurston Company boatyard. Designed by Dick Newick, the preeminent creator of trimarans at the time, the parts were then shipped to St. Croix, U.S. Virgin Islands, along with the identical hulls and amas for another set of boats, all of which were members of Newick’s Trice class. There, in St. Croix in 1969, Tryst was assembled and began life as a day charter boat, taking tourists out for short sails and snorkeling trips. Quote Link to post Share on other sites
tane 30 Posted April 6, 2020 Share Posted April 6, 2020 the australian Crowther Spindrift 38 "Dragonfly" in 87 broke up in the Indian Ocean, the crew, a family of four, were taken off by a merchant vessel. The owner, who had also built the boat himself, had previously increased the boyancy in the ends of the hulls by adding bulbs similar to Zingaros to the bows & & making the sterns fuller by adding foam & glassing it over. This probably increased the strain on the structure as did the overloading of the boat for long term cruising with 4 adults. I (1 rtw on a catamaran I built myself) allow myself the following comments: 1 some compartments in the boat look incredibly neclected: mould everywhere...the things that you see point to maintenance of the things that you don't see... 2. the owner lustily mixes "beams" & stringers" throwing doubt on his competence. 3. NOW he knows all the design faults, but they were staring him in the face all the time... begging for money after you wrecked your boat....you seem to know no shame! 2 Quote Link to post Share on other sites
Bruno 119 Posted June 25, 2020 Share Posted June 25, 2020 Looks like wide spread failure of material, design, workmanship, and maintenance, the quad-fecta. "zingaro m (plural zingari, feminine zingara) Gypsy quotations ▼ (offensive) a scruffy or slovenly person. tinker." I respect his miles and commitment to the cause (of cruising) but the boat doesn't seem to have been seaworthy. https://www.sailmagazine.com/multihulls/multihull-sailor-eulogy-for-zingaro 1 Quote Link to post Share on other sites
Officebob 0 Posted January 11 Share Posted January 11 How fitting a name!!! Quote Link to post Share on other sites
mpenman 87 Posted January 12 Share Posted January 12 On 3/3/2020 at 10:50 PM, Russell Brown said: Yep, and I still think it's perfect for building boats. Wood boatbuilding technology has improved just as fast as any other boat building material. I trust the stuff more than anything else, so stick it! Honest question, in high load areas you'd prefer wood over carbon? Quote Link to post Share on other sites
guerdon 149 Posted January 12 Share Posted January 12 The main difference between wood and carbon is notch strength. Carbon fiber is made of roasted rayon. When is is notched , it doesn't fatigue, its' stiffness transmits with explosive force . Wood is flexed during its' manufacture [50 years] so it gradually lets the surrounding area absorb the impact. While carbon is the sexy hookup, wood is the one that you marry. 4 Quote Link to post Share on other sites
mpenman 87 Posted January 12 Share Posted January 12 9 minutes ago, guerdon said: The main difference between wood and carbon is notch strength. Carbon fiber is made of roasted rayon. When is is notched , it doesn't fatigue, its' stiffness transmits with explosive force . Wood is flexed during its' manufacture [50 years] so it gradually lets the surrounding area absorb the impact. While carbon is the sexy hookup, wood is the one that you marry. Where for example would this be beneficial? The carbon is stiff and so any whack it translates throughout the boat. If would flexes so does everything else? Quote Link to post Share on other sites
oysterhead 56 Posted January 13 Share Posted January 13 Crowdfunded an Oyster 485 as the "replacement" boat. Going from 1 boat buck/month to keep things working to a lot, lot more might be a bit of a shock. Hand splicing dyneema off a bulk reel might not hold the new rig up either... https://svzingaro.com/ Quote Link to post Share on other sites
guerdon 149 Posted January 13 Share Posted January 13 mempenman, stress flows like water, carbon will transmit the stress to the nearest area that concentrates or occludes the impact if that area cannot shed the flow a crack/explosion will occur at that point. With FEA software and new computers many of the tragedies can now be predicted so you won't have incidents like in the past. The stiffness per pound give the nod to carbon, but you really need an autoclave to get consistent products. On the balance for one off race boats I still believe wood is superior for the long lived watercraft. 1 Quote Link to post Share on other sites
boardhead 213 Posted January 13 Share Posted January 13 Wood fibers orient in a growing tree to support the overall structure and that structural configuration is dictated by the species dna and the location and surrounding forest. Some grow tall and straight, others twisted and gnarly - appropriate filaments for specific examples refined over millennia - wood is great for making trees. So now we dis-assemble this structure and re-assemble bundles of filaments, selected as best we can from those offered by a diminished supply due to human vandalism, to create our man made structure - it’s a compromise. The stress risers and resultant failures being discussed here are the failure of the designer in recognizing and addressing the eventuality within the mechanical limitations of the selected filament - and that’s OK because there’s a lot to consider and it’s hard. When the selected build material (a bundle of pre-assembled cellulose fibers in the case of wood) makes ideal filament configuration difficult we turn to an alternative (glass, Kevlar, carbon,polyester) to help but there is still much to ponder in the orientation of those filaments and their bond to the underlying structure. Stress relief in a growing tree might be great for that structures development and survival but those filaments performance in their second life with our man made structure is dependent upon our selection and implementation. Starting out with individual filaments of known structural capability gives the engineer a more predictable outcome. Don’t blame the material, blame the designers selection and application. Quote Link to post Share on other sites
boardhead 213 Posted January 13 Share Posted January 13 On 1/12/2021 at 12:02 PM, guerdon said: The main difference between wood and carbon is notch strength. Carbon fiber is made of roasted rayon. When is is notched , it doesn't fatigue, its' stiffness transmits with explosive force . Wood is flexed during its' manufacture [50 years] so it gradually lets the surrounding area absorb the impact. While carbon is the sexy hookup, wood is the one that you marry. Are you talking about filament or matrix fail? Quote Link to post Share on other sites
mpenman 87 Posted January 14 Share Posted January 14 Carbon is extremely light, if you have enough of it, the need to flex is not as important IMHO. On a cat at least the primary area that would be subject to impact are the hulls. Just add another layer of carbon? Quote Link to post Share on other sites
Bruno 119 Posted January 14 Share Posted January 14 Carbon is highly flexible right up to its flexural limit, for a given load. It's also stiff up to that loading. And it's flex tolerant, more so than wood, up to its cyclic limit. It also binds well with resins. And it lends itself well to repeated processes. Within those limits it's a great material. 2 Quote Link to post Share on other sites
Zonker 2,866 Posted January 14 Share Posted January 14 On 1/12/2021 at 6:18 PM, guerdon said: but you really need an autoclave to get consistent products You can get very consistent results with wet bagged. They just won't have quite as many good properties. Quote Link to post Share on other sites
boardhead 213 Posted January 14 Share Posted January 14 Generalizing about “carbon” is confusing. The filament has spectacular tensile strength and when supported in column very good compressive numbers. Higher and lower modulus filaments, the ratio of filament to resin and that resins characteristics all yield different mechanical performance. Zingaro, suffered long term water absorption, degradation, delamination and flex fatigue which pretty much destroyed much of the wooden part of her structure. Dry wood expertly crafted and maintained has produced, what, hundreds on thousands of fine vessels. State of the art carbon fiber structures are so much more expensive and time consuming to build. As Zonker points out lower tech build methods also can have good results but don’t kid yourself you will get 787 wing performance. For myself the overall performance and life of well oriented glass filaments in vinyester resin over foam cores is tough to beat, bang for buck. Quote Link to post Share on other sites
Redreuben 80 Posted January 15 Share Posted January 15 Board head; look at Basalt Quote Link to post Share on other sites
Zonker 2,866 Posted January 15 Share Posted January 15 I live on a budget too. For me I use carbon where "stiffness in a small space" is the requirement. Or for carbon chainplates 'cause they look cool. 5 Quote Link to post Share on other sites
boardhead 213 Posted January 15 Share Posted January 15 I just use it in the mast where it has been engineered, braided, infused and autoclaved to justify the filaments potential and cost. Could not find anywhere else on the boat where it flies. My new chainplates, which incorporate the spectra lashing eyes, are 6061T6 alloy, cold and dark anodized and titanium bolted to the existing holes where the treacherous stainless steel (iron?) originals dwelt. The beautiful smooth finish in the eyes will let me sleep better avoiding the (small) potential that carbon would have for chafing through the lashings. Quote Link to post Share on other sites
Zonker 2,866 Posted January 15 Share Posted January 15 I would bet dyneema would easily chafe through the carbon. Just means you have something different to worry about If you want to do carbon with lashings, just do it like this: 1 Quote Link to post Share on other sites
TwoBirds 83 Posted January 15 Share Posted January 15 I'll certainly be far less cavalier about driving fasteners into beams and frames after watching that, quite amazing how solid most of the wood is after 40 years, I suppose the glue used in plywood has evolved significantly in the decades since Zingaro was built. Quote Link to post Share on other sites
boardhead 213 Posted January 15 Share Posted January 15 My Saint Francis is currently set up that way, new chainplates are finished but not installed - too cold and wet here right now - will share a picture when they are. In the meantime I will drill and radius a hole in a thick (same as the alloy) slab of quality carbon laminate I have and then slide a length of dyneema back and forth through it. Pretty confident the dyneema will start stranding in no time flat - will report back. 4 hours ago, Zonker said: I would bet dyneema would easily chafe through the carbon. Just means you have something different to worry about If you want to do carbon with lashings, just do it like this: Quote Link to post Share on other sites
Steve 80 Posted January 16 Share Posted January 16 3 hours ago, TwoBirds said: I'll certainly be far less cavalier about driving fasteners into beams and frames after watching that, quite amazing how solid most of the wood is after 40 years, I suppose the glue used in plywood has evolved significantly in the decades since Zingaro was built. I don't think the glue used in BS 1088 marine plywood has evolved at all in the last 50 years, it was a perfect product then as it is now. 1 Quote Link to post Share on other sites
ziper1221 16 Posted January 16 Share Posted January 16 On 1/14/2021 at 1:27 PM, Bruno said: Carbon is highly flexible right up to its flexural limit, for a given load. It's also stiff up to that loading. And it's flex tolerant, more so than wood, up to its cyclic limit. It also binds well with resins. And it lends itself well to repeated processes. Within those limits it's a great material. How can it be flexible and stiff? Quote Link to post Share on other sites
Bruno 119 Posted January 16 Share Posted January 16 Pick up a driver then tell me. Quote Link to post Share on other sites
Zonker 2,866 Posted January 16 Share Posted January 16 Carbon is not what engineers call flexible. Strain to failure is around 1%. 1 Quote Link to post Share on other sites
mpenman 87 Posted January 16 Share Posted January 16 On 1/15/2021 at 1:30 AM, Zonker said: I live on a budget too. For me I use carbon where "stiffness in a small space" is the requirement. Or for carbon chainplates 'cause they look cool. How much more is carbon than wood? How would you build a cat? I understand on my boat for example, that we have a foam core with a mix of carbon and glass fibers and epoxy. How would you use wood in this example, besides the bulkheads. Quote Link to post Share on other sites
Bruno 119 Posted January 17 Share Posted January 17 Right, not as flexible as glass, racing masts have more carbon, wave masts more glass, but it is predictably flexible under a given load to a certain limit over a known cyclic life. Combining it in thin layers with more flexible materials is usually not an effective solution. Adding carbon stringers can work but for much less cost so can glass stringers, ntm glass usually lays up easier. Carbon does what it does but it ain't pixie dust. Point about a driver is it adds stiffness and controlled flex in a weight efficient laminate. Quote Link to post Share on other sites
Bruno 119 Posted January 17 Share Posted January 17 How much more is carbon than wood? How far away is Mars? Compared to koa it's much cheaper. Quote Link to post Share on other sites
mpenman 87 Posted January 17 Share Posted January 17 3 hours ago, Bruno said: How much more is carbon than wood? How far away is Mars? Compared to koa it's much cheaper. I'm not sure that I agree with that statement. On a catamaran hull you most probably have 4-5 layers on the outer skin and 4 on the inner right? I'm still confused as to where the wood goes and how it's cheaper? Quote Link to post Share on other sites
Bruno 119 Posted January 18 Share Posted January 18 So racing boats tend to have thin carbon skins over thick cores, if nomex then glue sheets etc. This is an expensive strong sandwich that is relatively easily punctured and dented. Not a big deal given heavy crews, docking assists, lots of pads, able skippers, etc. Those solo racers rarely dock solo. This is also an expensive solution, carbon and thick cores are costly. Glass, especially S glass, is a bit tougher in some ways, yields rather than breaks, good with abrasion, the thicker lams required to get panel stiffness are harder to puncture and dent, thinner cores (due to cost and thicker skins) are usually of more durable materials and density. Monolithic is better for impacts and delams. Knitted tends to resist abrasion peeling better, etc. Ability to mix types etc. Good s3condary bonding for internal structures under the right conditions blah blah. The most common mistake I see other than shit workmanship is applying a thin layer of carbon, particularly uni, on a buckled or broken glass surface. This rarely works. 1 Quote Link to post Share on other sites
Bruno 119 Posted January 19 Share Posted January 19 ...tends to not...my bad Quote Link to post Share on other sites
Zonker 2,866 Posted January 19 Share Posted January 19 On 1/17/2021 at 3:05 PM, mpenman said: On a catamaran hull you most probably have 4-5 layers on the outer skin and 4 on the inner right? Glass and carbon come in many different weights so saying "layers" is very general. Also the orientation varies. And of course the type of glass (like cheap production boats that throw some good old mat in there to bulk up the skins. Our hulls were quite thick but only 2 layers I think. They were 2 x 1708 - which is itself a mat layer and a stitched biaxial layer. Total weight of fabric 2 x (17+8) = 50 oz/sq yd. On the underside of our bridgedeck I used 2 layers of a custom triaxial I had woven for me. It was 20 oz (666 gm) x 2 = 40 oz/sq. yd. All in glass. Some Aussie cat designers use ~600 gm/m2 (18 oz) for the outer hull skin. It works but is not very puncture resistant. Might not have a lot of safety factor on even some local loads like hitting a log. 1 Quote Link to post Share on other sites
TwoBirds 83 Posted January 19 Share Posted January 19 one thing I like about wood is it's compatible with all other kinds of wood, you don't have to call the manufacturer to find out if it's ok to use fir with cedar 1 Quote Link to post Share on other sites
KC375 1,688 Posted January 19 Share Posted January 19 1 hour ago, TwoBirds said: one thing I like about wood is it's compatible with all other kinds of wood, you don't have to call the manufacturer to find out if it's ok to use fir with cedar just in case I need it can you you pass on the phone number, I have some existential question I might need help with 1 Quote Link to post Share on other sites
TwoBirds 83 Posted January 19 Share Posted January 19 10 minutes ago, KC375 said: just in case I need it can you you pass on the phone number, I have some existential question I might need help with I hear it's $500,000 dollar phone call from anywhere but Ireland where it's only 5p 'cause it's a local call Quote Link to post Share on other sites
Steve 80 Posted January 21 Share Posted January 21 Meade Gougeons Adagio trimaran is a good example of the longevity of a well built and well maintained lightweight multihull, 35ft x 2400lb okoume plywood /epoxy, 50 years old and still winning races on the great lakes. I read a lot of negative comments about various materials such as plywood or balsa core. I have done more than my share of core replacement and while personally I prefer foam cores for my own boats I have yet to see a rotten balsa core that was the fault of the balsa, it is always a human at fault, be it the builder cutting corners or a negligent owner. Same goes for plywood boats, assuming good build practices, just a reasonable level of maintenance is all that is needed for a very long life. I'm not talking high maintenance either, just keep the damn thing dry, well ventilated and repair damage and leaks as soon as they happen. Quote Link to post Share on other sites
Russell Brown 806 Posted January 21 Share Posted January 21 Just got to check out a cool older ply/epoxy race boat last night. It's a 27 footer that looks a lot like a Moore 24. Built in the 80's. The construction is a bit rough and ready, but inside it looks like new. No dark spots in the bilge or anywhere else I could see. Really quick apparently. it's getting a cockpitectomy for the Pac cup. Quote Link to post Share on other sites
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