The panels of a boat's structure must be designed to withstand a number of different stresses. Chainplate popped out when sailing - what's next? There is no other choice. Copyright 1999-2022 Boats Group. Please do not compare the amounts of glass and resin for a plywood core to a foam core. Two densities of balsa are shown. Thin-cored laminates generally have thicker skins, which means more fiberglass, more labor, and so more cost for the lay-up. To resist all these stresses without fracturing, a single-skin laminate must be relatively thick and heavy. The ply version only uses tape for seams, no ply skin. With all my over build the completed hull is 150lb. Plywood can at least do single curvature reasonably well, but cant do compound curves. Many people wonder how modern fiberglass boats are built, and boat building today is not at all like it was back when antique and classic powerboats were built. These days, boat building is actually pretty high-tech. In a single-skin laminate, the outside surface is in tension, the inside surface is in compression, and the middle is in shear. I took measures from the moulds. Use the core only as the manufacturer intended it to be used. Plastic cores are being used increasingly as structural cores in hulls and decks, and in interior joinery. Again, the designer must engineer the answer. by Jeff Fri Sep 14, 2018 8:02 am, Post With over two decades of experience in marine journalism, Lenny Rudow has contributed to publications including YachtWorld, boats.com, Boating Magazine, Marlin Magazine, Boating World, Saltwater Sportsman, Texas Fish & Game, and many others. A heavy boat with a lenght of ten feet or three meter must have very compund curves with small radiuses. Powered by vBulletin Version 3.8.8 Beta 1. densities being the most common in boat building. 1980s VDO Wind Indicator System -Replacement Masthead Unit, VDO Instruments - Installation Documents - 1980s. It is closed-cell polyvinyl chloride, was and still is one of the best of all foam cores. Nida-Core has solved this problem with their polypropylene core by using a polyethylene film to fuse a non-woven polyester scrim to both sides of the core. To achieve total contact between core and outer skin, most builders nowadays use vacuum bag techniques, employing the same sealing principle that keeps packaged bologna fresh in the supermarket. Before it cures, they press the core blindly into the wet laminate. ft., with 5-10 lb. Shear is the tendency of the inside and outside halves of the laminate to slide against each other in opposite directions. Photo by Regulator Boats. How to Buy a Boat: Tips for a First Time Buyer, Top 10 New Fishing Boats for Under $20,000, What Type is Right for You? Boat Building general. Above: Overhead cranes are often used to lift major boat parts, like this hull for a Regulator fishing boat, out of the molds and into position for further assembly. 9, Factory Fridays: Twin Vee PowerCats Pioneers Boat Building Innovations, Understanding Foam Cored Boat Construction, Factory Fridays EP. By Eric W. Sponberg, Naval Architect The following article first appeared in American Sailor magazine. Unlike RTM, SCRIMP(tm) requires only one tool side in conjunction with a flexible bag. The foam doesnt soak up as much epoxy as plywood. Check to see if any of the hull and deck surface flex's when you give it a tap with a hammer or the back of a plastic handle screwdriver. In glass laminated boats, epoxy's superiority to polyester resisn as a stable moisture resistant adhesive reduces the possibility of delamination and gelcoat blistering caused by moisture penetration. Please include the boat type in your question. Through epoxy composite construction, the builder can offer boats in a wide range of designs, materials and construction methods. Like Copacabana I view divinycell as a plus. Baltek's putty is called Baltek-Bond and is used with its balsa core products. It is a mistake to design and build skins that are too thin. Photo Credit: Sabre Yachts. Lenny is a graduate of the Westlawn School of Yacht Design, and he has won numerous BWI and OWAA writing awards. During this time, the properties of Divinycell foams have been continuously enhanced and improved so that it continues to be ideal for the vast majority of sandwich composite applications. The one product available is called Core-Cell which is manufactured and marketed by ATC Chemical Corporation of Buffalo, NY. Over the years, thousands of composite recreational and working boats have been built and the earliest are still going strong. The Divinycell i bought frome store over here is prescored. Then vedges were glued betveen the quadrangels, held in place with nails untill the glue set. Basically, it combines the linear, non-brittle features of Airex in a broad range of densities like Divinycell, from 3-12 lbs./cu. Exlex the sailing canoe is a new product: The laminators cannot see if the core is in perfect contact to the skin on every square inch of surface. A thin skin can bend out of line so much that it breaks away from the core, causing radical delamination. A rough provisional estimation of the itinerary for my Cape Horn doubling. Corebond and a vacuum bag would work well if the shape was supported. In production boat building, the laminating crew lays the outside skin into a female mold first. To vacuum bag a core, laminators first lay a bleeder cloth over the core, and over that they drape a large sheet of plastic film the "bag" and seal its edges all around with a special thick, sticky, sealing tape. Because of this separation of duties, the skins together can be less thick than the total thickness of its single-skin counterpart. Next step is to shape the foam. In small boats there would be no weight advantage and would cost more to build " more epoxy and glass ". Everything from strip canoes to work boats, high performance multihulls to offshore racing powerboats have been built using epoxy composite construction. by Fuzz Thu Sep 13, 2018 9:31 pm, Post Not only does this eliminate the need for masks, gloves, and protective clothing, but it means a cleaner, healthier production setting and environment. For more than 30 years Divinycell has been the first choice of leading producers of sandwich composite structures around the world. Finally, which core material is the building crew most experienced with? I too did more layers of glass than what would be used on wood. And then divinycell i biught has a mesh (net) on the side you cant see on the picture and its prescored so what i learnd is that it dosent need vacuumbaging, instead i will put a even pressure by putting weights on top of it all over the fomed area. The Mountain Bike of the Oceans. The bag is left in place until the outside skin cures with the core stuck to it. This makes the cored-skin laminate stiffer. The boat is unique. How thick should the core be? Linear PVC is not chemically cross-linked and does not break when bent. They must be perfectly sealed against. With virtually no size limitations, the SCRIMP(tm) process can produce large and small components, as well as complex, multidimensional trussed parts. The explosive growth of fiberglass-polyester boats over the last thirty years was built on the perception of low maintenance and easy fabrication. ft. to 25 lbs./cu. Delamination would be my worry. Its just a bit more work into filling the scoring with thickend resin (not thick like faringcompund, just lightly thickend). Please support our sponsors and let them know you heard about their products on Cruisers Forums. I divided the endships, fore and aft into a number of quadrangels. by fishgitr Sun Sep 16, 2018 2:26 am, Post See the thread from FishGitR, he is building a 16 foot ConchFish from Divinycell!! You can thermoform divinycell. A pattern was made. In addition, cores insulate the hull against heat and cold, dampen vibration from slamming seas, and deaden the sound of chugging engines. This depends directly and entirely on the size of the boat, the size of the hull panels, and the anticipated loads. These molds will be used to create Bavaria powerboats. Although many modern boatbuilders eschew the use of wood, on high-end custom yachts like this Jarrett Bay, methods like cold molding are often considered superior to more modern techniques. by Jaysen Sun Sep 16, 2018 7:07 am, Post A stronger and stiffer core such as balsa can be thinner, and the weaker cores must be thicker. Thanks to cores, boats have better performance and enhanced creature comforts. Press J to jump to the feed. They are made of a number of materials: Of these, Nomex is the most expensive and is used primarily in custom boats. The solution to these problems lies in epoxy composite construction. You must look at the total ply stack of the laminate schedule when comparing core and laminate weights, strength, stiffness, and cost. Looks good! The development of fiber reinforced plastics (FRP) offered apparent solutions in new materials and techniques. The SCRIMP(tm) process can be used to infuse thick laminates with the same high quality results as a simple 1/8" laminate. The primary developer and major manufacturer of end-grain balsa core is Baltek Corporation of Northvale, NJ. The in-depth series gives viewers exclusive access to the innovators and craftsmen behind some of the best boat brands in the world and a firsthand look at the latest boat building techniques and materials used inside their plants. SCRIMP made composites exhibit the same material properties as those produced by more expensive processes. However, as with wood, polyester resins have been plagued by the effects of moisture penetration. My v12 was my first build. My 1989 Swan 43 has Divinicel cored decks (and longitudinal hull stringers). Don't guess, have somebody with experience do the math. To get strenght, boyancy and insulation for the southern winter combined with as low weight as possible I have chosen a sandwich core of 40 mm ( nearly 2 inch ) Divinycell foam of 100 kilo per cubic meter density. Questions before purchasing the plans and announcements.. Cracker Larry's Corner: Boat Repair and Rebuild Support, Core Materials: Plywood, Foam core and Honeycomb, Builders' Tips, Tools, and Tricks of the trade. Balsa, PVC and SAN foams require special putties to assist in bonding the core to the outside skin. The pattern was tried for accuracy and corrections were made, then the Divinycell quadrangel was cut out and hold in place with temporary scruvs. Epoxy composite construction consists of bonding all of the materials and parts of the boat together with epoxy resin. By understanding how a boat's structure is designed and how it works, you can compare these core materials for yourself. Workers can apply material to a mold much more easily when not encumbered by respirators, gloves and resin suits. It is impossible to bend that kind of Divinycell into that shape. In summary, core materials make boats stiffer and lighter. Composite construction includes a variety of building methods that use epoxy to protect the materials from moisture as well as hold the materials together. Divinycell H provides excellent mechanical properties to low Divinycell HM is designed with exceptional toughness for fast Divinycell HP offers elevated temperature performance with Divinycell PY is based on PET, which makes it a recyclable, 2022 ATL Composites. Questions before purchasing the plans and announcements.. Cracker Larry's Corner: Boat Repair and Rebuild Support, Core Materials: Plywood, Foam core and Honeycomb, Builders' Tips, Tools, and Tricks of the trade, Builder's Progress and non technical messages. Photo by Mystic Powerboats. Use proper engineering and design procedures. Above: From innovative marine propulsion systems and cutting-edge onboard technology, to the advanced physics of computerized hull design, boat builders share their fascinating stories and unique approaches to constructing and engineering a variety of watercraft in the Factory Friday video series from boats.com. In general, balsa and aramid honeycomb are stronger and stiffer in shear than the other core materials. Note, however, that the heavier balsa core is less costly than the lighter balsa. Divinycell foam are compatible with virtually all commonly used resin systems ( vinyl ester, polyester and epoxy) and has been used in land transportation, marine (pleasure, military and commerical) wind energy, civil engineering/infrastructure and general industrial markets. Void-free surfaces do not require filler in painted applications or expensive rework associated with "egg shell" effects. The basic guidelines that designers and builders must follow are: Most cored/laminate failures can be traced to a violation of one of these rules. Me next to the boat. Advantages of Epoxy Composite Construction, Nomex, with aramid fiber, is made by Hexcel Composites, Dublin, CA, Plastic, Nida-Core, from Nida-Core Corporation, Hoboken, NJ, Paper, called Tricel, from Tricel Corporation, Gurnee, IL. All rights reserved. Click on them once or twice to enlarge. The putty is spread over the skin before it cures, then the core is pre-coated with resin and pressed into the putty. Google Compared to polyester resins typically used in fiberglass boat construction, epoxies have greater strength, less shrinkage, better moisture resistance and better fatigue resistance. And, depending on the engineering circumstances, a low-density, thick core could have the same weight as a high-density thin core for the same shear strength and stiffness. The inside fiberglass skin presents no problem when laminating because the laminators can see the core surface as they lay down the transparent wet fiberglass laminate. And because cores are very lightweight, the cored-skin laminate weighs less than the single-skin laminate. The bond of the skins to the core must be perfect. 8, Twin Vee PowerCats, How to Buy a Boat: Tips for First Time Buyers. The worst loads are imposed by wave impacts against the sides and bottom of the hull. Cores make the hull of the boat stiff and light. Boats up to 15' for oars, power or sail. Jeff. Twitter. VERSATILITY The builder using composite technology can build boats with a range of materials, designs, and construction methods that are perfectly suited to the boat's use and the customer's needs. Cores are made from a variety of materials which have different strengths and stiffnesses. ft. The portside is still 100% good. The cross-linked is brittle and, if bent too much, it breaks. The choice as to which core is best for a particular design usually reduces to which core is the least expensive for the greatest strength and stiffness. You need at least twice the amount of glass and epoxy on a foam cored hull. Welcome to Yrvinds website: small boat designer, builder, sailor & writer. As air is removed, the outside air pressure presses the core uniformly into the entire surface of the skin. I wont go over 20.. the other guy is around 15 gallons in and hasnt built a cap yet. Designers, builders and owners have more choices available. Balsa core and the higher densities of Divinycell and Klegecell have sufficient compression properties to resist such crushing loads, but the other cores must be removed and replaced with solid wood or structural putties in areas where through-bolting occurs. Available in Ready-to-Use Kits and Various Finishes. Under these loads, the panel bends and experiences stresses within the laminate. The resulting structure has physical characteristics superior to the components by themselves. Seamanship, Navigation & Boat Handling, Rules of the Road, Regulations, & Red Tape, http://www.fiberglasssupply.com/pdf/moformDiab.pdf. SCRIMP(tm), unlike prepreg, does not require refrigerated storage, time-consuming debulking, breathers, bleeders, and porous releases, or the scrap associated with bridging. Because lay-up is performed with dry materials, workers are not exposed to wet resin. Youd want an h200 or better for that application , and that stuff is dense. Environmentally responsible, SCRIMP(tm) is a completely closed system that traps VOC emissions instead of sending them up the stack. Above: The development of serious speed boats, like this Mystic catamaran, played a significant role as manufacturers learned how to minimize weight. Composite construction has proved itself at the top levels of competition in sail and powerboat racing, in the harshest environments and under the toughest working conditions. I did not even consider it. Depends on what application you using Divinycell for. This leads to serious blistering, delamination, and even considerable weight gain, particularly in honeycomb hulls where water can fill up all the open cells. Follow the core manufacturer's instructions. Tension and compression are generally easy to visualize. Of course a quadrangel can never be trusted therefore they were turned into triangels always reliabel. SCRIMP(tm) is a process called resin infusion molding. by garym Thu Sep 13, 2018 4:54 pm, Post LOWER MAINTENANCE All of the components in a composite boat are protected by an epoxy moisture barrier. ft. Any posts related to repair and maintenance, new builds, tools, sail making, boat upholstery, motors, electrical, hydraulics, plans, etc. Since cores resist shear stress, designers compare different kinds primarily by their shear strength and shear modulus. All rights reserved. Press question mark to learn the rest of the keyboard shortcuts. In fact, measured levels of VOCs are lower than 10ppm. At the ends of the strip, the inside surface of the laminate is in compression, the middle region is in shear, and the outside surface is in tension. High compressive properties are necessary to resist the crushing loads of through-bolts wherever hardware such as winches, tracks, and cleats are mounted. Paper core is becoming increasingly common in boat interior joinery, but is not recommended for hull and deck structures. One of the pattern and a paper with the measurments. Used 2x epoxy and did 12oz bottom. You must also account for the weights of the skins that result from any given core material and thickness. Epoxy provides a stable base for paints and varnishes, reducing the frequency of refinishing. Top 10 Choices for Boaters, Fiberglass Repair, Epoxy, Resin, and Help, Factory Fridays: Cigarette Racing Team's Boat Building Process - EP. ft. density. SCRIMP composites, with or without a gel coat, exhibit near-perfect surface quality. But a cored-skin boat designed and built with care will last for years, while you enjoy the extra performance and creature comforts. Idk another guy and I are both building the Conchfish. Different density and or thickness will determine how long it takes. by jacquesmm Sun Sep 16, 2018 5:43 pm, Users browsing this forum: No registered users and 0 guests, Powered by phpBB Forum Software phpBB Limited, Style we_universal created by INVENTEA & v12mike, Facebook ft. Honeycombs used to be pretty expensive (some still are), and as such, were rarely used in production boats and only in the most expensive one-offs. Epoxy composite boats have set a standard for performance, reliability and beauty. Most widely used throughout the world, balsa core is made with the wood grain running from skin to skin and is termed end-grain balsa. Diab Inc. markets putties called Divilette (for Divinycell), K-Lite (for Klegecell), and ProBond (for ProBalsa),. Cores, however, must be quite thick, and so the total thickness of the cored-skin laminate is more than a single-skin laminate. Note, too, that core mechanical properties increase significantly with density the denser the core, the stronger and stiffer it is. In boats.com's Factory Fridays video series we tour boatings top manufacturing facilities across America. Can anyone give me the pros and cons of divinycell foam, Location: Thunder Bay, Ontario - 48-29N x 89-20W, Look at any penetrations of the cored areas. It comes in only two densities, 3.8 and 5.5 lbs./cu. Baltek supplies core in densities of 6.5, 9.5 and 15.5 lbs./cu .ft. Properties are from manufacturers' published data for approximately 6.0 lb./cu. Can Divinycell be used in place of marine plywood for the V12? SAN foam is a new core material that has been developed since this article was first written ten years ago. Finally, thin laminates are not very durable against minor impacts such as the hull bumping against a dock. Ive seen no problems with them at all, and I have been assured that. Nice work. Just wondering your method. Because the SCRIMP(tm) system achieves equilibrium resin content (50% to 70% fiber weight, depending on fiber architecture), unlike most composite processes, it is inherently repeatable. I am pretty much done besides a little fairing. Builders use the moisture resistant qualities of epoxy to take advantage of wood's strength, stiffness, light weight, resistance to fatigue, insulating ability, availability, cost, and beauty. Lightness means less weight to move through the water, so speed is faster. I have therefore developed a unique building method. Technical Support Message Board and Builder Forums. WEST SYSTEM and PRO-SET are registered trademarks of Gougeon Brothers, Inc., PO Box 908, Bay City, MI 48707-0908, U.S.A. Email comments or suggestions to webmaster@gougeon.com. Copyright 1998. Measures were taken as good as possible. Foam is really easy to work with too. Shear is highest right in the middle of the laminate. All rights reserved. SCRIMP's closed-mold technology brings styrene levels down well below today's stringent standards, and eliminates the need for the costly exchange of heated air. Since the moisture content is stabilized, the maintenance problems associated with wooden boats - rot, joint cracks, structural members swelling or shrinking, and surface checking - are eliminated. Epoxy's excellent adhesion to balsa and plastic foam cores, glass, aramid and carbon fabrics, allows the builder the advantage of selectively integrating these materials into the boat's structure. Privacy Guaranteed - your email is never shared with anyone, opt out any time. Controlled bagging of performs and repeatable resin infusions enable any licensed fabricator to perfectly produce and reproduce specifically designed, high-quality precision parts with consistent dimensional accuracy. A HISTORY OF SUCCESS Epoxy composite construction techniques for boat building were first developed over thirty years ago. boats.com is part of the Boats Group Network. Each kind of core requires slightly different laminating techniques, and different building crews tend to have developed their own preferences. Above: In the modern age, building a boat begins with a mold. Just recently (late 1999), Baltek has announced the availability of SuperLite, a range of lightweight balsa cores from 4.9 to 8.7 lbs./cu. Im curious How would you say divinycell foam compares to plywood in terms of forming? by fishgitr Sun Sep 16, 2018 3:31 pm, Post How did you do the scoring on the foam? The designer must solve this engineering problem for every single panel in the hull and deck. Videos about Exlexs sails and Yrvinds next design, Five videos presenting some of Yrvinds ideas. These subdivide the hull laminate into panels. are welcome. Is divineycell foam same, better or worse? The skins should be as thin as possible, consistent with strength, stiffness, ease of lay-up, and overall hull durability. If youre talking about a transom, more like ply wood. Post Details can be seen of quadrangels and wedges and glue oozing out. Diab also markets an end-grain balsa core called ProBalsa in densities of 5.6, 9.7, and 13.8 lbs./cu. If paper core gets wet, it goes all mushy, just like cardboard left out in the rain. This manner of bonding is very difficult to achieve on every single cell wall. Divinycell is available in different grades--I think from memory the orange coloured stuff is the best. boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. I agree with too as you will use more glass. Im doing it in foam and Im at just over 19 gallons. Au-Struck: A Journey Along the East Australian Current. For a non-stop sail of one year the boat has no other choice than to be heavy. Each panel experiences water pressure and wave impacts from the sea. Like mechanical properties, prices go up with increasing density. Since cores are an integral part of the boat's structure, the designer must take proper account of these properties so that hull and deck laminates won't fail. When the glue had set. Panels are usually analyzed by looking at a strip of laminate that is the shortest distance between two internal structural members such as longitudinal stringers or bulkheads. Note the small numbers at the edge of the pattern. To contact me please phone as I dislike writing letters and e-mail. The most common core materials utilized in building boat hulls and decks include balsa wood, PVC (polyvinyl chloride) foam, SAN (styreneacrylonitrile) foam, and honeycombs made from aramid (Kevlar), plastic, and paper. by topwater Sun Sep 16, 2018 7:40 am, Post A NEW INTEGRATED MATERIALS TECHNOLOGY Combining the best of wood technology with the advances in FRP materials and processes, leading builders have turned to composite construction to produce durable, distinctive boats. WHAT IS EPOXY COMPOSITE CONSTRUCTION? Here follows some pictures. Stiffness means the hull does not flex out of shape, which would increase hydrodynamic drag and slow the boat down. Above: You can see the core (with checkered appearance) in this part, about to be vacuum-bagged at Sabre Yachts. This is a cockpit/wheelhouseroof where i had waterinstrusion and the woodcore more or less decomposed on the starbord side. More glass and more epoxy!! Most sailboats racing IMS, PHRF, and one-design are built with at least one kind of core in their hull and deck laminates, and for good reason. Something Good is Brewing in the Sportfishing Community, Introducing Afuera Coffee Co. ATC Chemicals markets a putty called Core-Bond for their Core-Cell core. Cross-linked PVC cores are Divinycell and Klegecell, both marketed by Diab Group of DeSoto, Texas. Twenty-five years of advances in construction techniques using epoxy-bonded materials have revolutionized boat building and set new standards for performance and reliability. A look at basic boat construction, fiberglass technology, and the fundamentals that modern boat builders use. Photo by Bavaria Boats. Modulus means stiffness the higher the modulus, the stiffer the material. In a cored-skin laminate, the outside and inside skins experience the tension and compression stresses, and the core experiences the shear stress. Engineering can check fiber orientation prior to infusion. Just enough wet fiberglass or bonding material must be used for a good bond, but excessive amounts of resin will fill up the honeycomb cells, making the boat way too heavy. It is the corections. The deflection of the strip is greatest in the middle, but the stresses there are only half what they are at the ends of the strip. An air suction pipe is installed into the bag, and the air between the bag and core is sucked out through the pipe by a vacuum pump. The thicker the core, the thinner the skins can be, and so the lighter the laminate. Instead I chose the bricklaying method, building the boat of small bricks or tiles or quadrangels of Divinycell. SCRIMP(tm) involves using a vacuum to force resin through a laminate at a controlled ratio. Properties vary significantly with density the denser the material, the stronger and stiffer it is. This is because more labor is require to hand-select the correct densities of balsa stock to make up the core panels. The Divinycell i bought frome store over here is prescored and that makes the forming a nobrainer. It is available in a broad range of densities, from 3 lbs./cu. The weight of different cores is less important because they tend to be only a small portion of the total laminate weight. Below is some text, courtesy of Tillitson-Pearson regarding the scrimp process they developed in the mid eighties. SCRIMP(tm) saves labor and time with dry lay-up. Generally, you cannot isolate the core out of the laminate for comparison. The scrim and film provide the appropriate bond to the honeycomb. Composites can be uncomplicated structures of wood and wood veneer or complex vacuum laminated hybrids incorporating glass fabrics, aramid, or carbon fibers.
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