Interesting conversation, and thank you for asking for my input. Apologies for a late reply though, I've been up to my eyebrows, on behalf of the Marine Museum, in organizing the upcoming Canadian Sailing Hall of Fame Inductions on October 3rd in Kingston.
I started my career in the marine industry designing with C&C in the late '60s, and finished it in sales and marketing with Baltek in New Jersey from 2003 to 2011. I thought it was appropriate to wrap up my career with Baltek, since balsa core was such an integral part of my design work with C&C. It felt like closing a circle. However,the Baltek offices at the time being only 45 minutes from Manhattan was also a consideration. What has been discussed to date is essentially accurate. The Kohn family did escape from France in the early days of the 2nd WW and established business in New York City. Jacque Kohn spent time among their balsa plantations in Ecuador increasing the production of balsa wood, which at the time was considered a "strategic material" for the war effort, specifically for use in Navy carley floats and liferafts, and as mentioned previously for the Mosquito fighter/bomber, the wooden wonder. However, it was planks of flat-grain balsa that were used as a coring material in the fuselage between laminated birch skins, not end-grain. The fuselage was laid up over male molds in two halves then joined together after the electrical and hydraulics had been run down each side of the fuselage interior. Most of this work was done by women. After the war, of course, demand for basa plummeted, resulting in a search for new markets other than model airplanes and fishing floats. One large market that developed was for insulation in LNG tankers, but that too died out with the development of new shipping methods. The story of Everet Pearson and the invention of end-grain balsa through Alex Lippay is essentially true, but others were also experimenting with end-grain balsa as a core, specifically in the aircraft industry. Adding a scrim to blocks of end-grain balsa allowed the material to be applied in 2'x4' sheets and allowed the sheet to contour to the shape of the deck initially and then hulls. The advantage of end-grain over flat-grain as a core material, of course, is the exceptional increase in both compression strength and shear strength. End-grain balsa is essentially a honeycomb. The use of end-grain balsa between two load bearing skins created an engineered panel not unlike a three dimensional I-beam. It greatly increased stiffness and reduced weight compared to a single skin glass panel of the same strength. Initially it was used extensively in decks only. The first use in a hull laminate was with the building of *Red Jacket* in 1965 (see latest issue of Good Old Boat). It was Alex Lippay who guided Cuthbertson & Cassian and Erich Bruckmann in the building of *Red Jacket*. Bruckmann, of course, had never built a fiberglass boat in his life, let alone the most advanced composite laminate todate! Back in 2003 when I told George Cuthbertson that I was joining Baltek he asked me if Alex Lippay was still there. Alex, of course, had passed away many years ago, but was still immortalized at Baltek in the designation for the precoating on balsa which was known as AL-600. Jacque and Margot Kohn, then in their '80s, were also still there, but had recently sold the company to Alcan, and were phasing out of the operations. Both Jacque and Margot, too, have since passed away. Working at Baltek was an amazing experience and I still maintain close friendships with the people who were there, most having worked their whole careers with the company. It was literally a family run business. The Alcan acquisition, and subsequent later acquisitions, of course, changed that, and the company suffered because of management by people who often did not understand the lumber business. With the success of* Red Jacket*, C&C Yachts was created in 1969, and all three builders (Bruckmann, Hinterhoeller, and Morch) embraced balsa core construction for hulls and decks. Most of my time at Baltek was teaching builders, even as late as the 2000s how to install core correctly - fillet all edges, prewet before installing, fill all kerfs, isolate the core from all openings, vacuum bag or infuse if possible, etc,. etc. If installed properly, balsa core will last forever.* Red Jacket's* hull is a testament to that. Her deck, not so much! People will willy-nilly drill holes in decks, but not hulls.* Red Jacket*, of course, has recently been donated to the Marine Museum of the Great Lakes at Kingston. Her arrival has been delayed due to the complications of Covid. Reference has been made to Dan Spurr's excellent book Heart of Glass. Dan is a long time friend and my editor at both Professional Boatbuilder magazine and Good Old Boat magazine. Anyone interested in the history of fiberglass boat building needs to have a copy of that book in their library. It even has a chapter on Canadian boatbuilders. Anyway, I'm not sure if that's what you were looking for, but this is a topic that is of great interest to me, having worked both on the design and building side with C&C, Mark Ellis and Hunter Marine, and on the sales and marketing side of core materials with ATC (Corecell) and Baltek (Balsa, PVC, and PET). In the immortal words of Paul Pfund, when it comes to core installation, if you're not going to do it right, don't do it at all! By the way, I should mention that the Baltek labs under the management of Dr. Kurt Feightinger are second to none. The amount of data that they have available on all core materials is impressive. While I was there we did a complete study on the properties of wet balsa specifically aimed at Sea Ray, but the results were interesting, to say the least. Wet balsa even at 100% saturation is still stronger than most foam cores. However, if decay sets in, then that's a different story. Their design expertise headed by Russ Elkin is also impressive. Thus endeth the epistle. Rob Mazza On Thu, Sep 16, 2021 at 6:22 PM Lisle Kingery, PhD via CnC-List < cnc-list@cnc-list.com> wrote: > FWIW, this prompted me to take a look at the book "Heart of Glass: > Fiberglass boats and the men who made them": and some info on Balsa is on > p122, > > "Balsa Core. The Baltek Corporation was the exclusive supplier to > powerboat builders of balsa planks for stiffening hull sides and bottoms. > When balsa was originally supplied in lengths with the grain running > longitudinally, Pearson had problems with water migrating away from the > point of entry at the deck hardware fasteners, causing delamination. > Everett Perason recalls that "We were using pieces 3 feet long by 1/2 inch > thick by 2 inches wide. We had some leaks at the fittings, which didn't > make any sense. So I started stacking this stuff up and cutting it on the > bandsaw and making end-grain balsa. I was doing that on Constitution Street > when Alex Lippay and Bob Levine came in from Baltek. They said "What are > you doing". I sadi "I got to turn this stuff the other way to stop the > water from spreading. They said "Jeez, this is what we should be doing." I > said "You're right". That's how Contourkore started. They took the > end-grain idea and made samples that we evaluated. They came up with a > method of putting scrim on it and so forth. In hindsight, I should have > applied for a patent. I think we were probably one of the first to use > Contourkore, as early as 1963 in a race boat hull. THe new product was > brought to market in 1963 and 1964, with Pearson as one of the its > first few users and most vocal supporters. Indeed, in 1981, Pearson sank a > 2-square-foot basl cored panel in Narragansett Bay, attached by change to > his dock. After three years he removed the panel from the water and had it > analyzed. The results? No water penetrated the balso more than 4 mils." > > Best, > > Lisle > > >
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