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#1
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| Blue Gum as boatbuilding wood I would like to gather this forum participants' opinions and experiences in the use of Blue Gum (Eucaliptus globulus, globulus) for ships and boats building. Blue Gum provides one of the better woods for boatbuilding, when properly treated. Even better that English Oak. Originally this tree came from Tasmania. 100 years ago the "Blue Gum Clippers" were built there almost entirely in Blue Gum and Huon Pine, being the envy of nations reputed as the best in shipbuilding. Even Lloyd's charged lower insurance fees for those ships. When Blue Gums are grown in densities of around 135 individuals per Ha, for 35-40 years, are abated properly and the logs sawed in the correct pattern, we get one of the better construction woods available. It is heavy (density bigger than 0.9T/m3), flexible, hard (this is the only difficulty for working with this wood) and with an extraordinary resistance to rot in sea water (logs of eucaliptus were extensively used for supporting piles in harbour docks and train rail traverses, with periods of replacement sometimes as high as 35 years). In Galicia all the boatyards still producing fishing boats in wood (Around 25), use eucaliptus thoroughly for the structure of the boats, with excellent results. Any other experiences? |
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#2
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Today they are all gone. No more wood boatbuilding and the one that is made in other materials (steel and fiberglass) is just a shadow of what was once a flourishing industry. What finished it was not only the competition of other materials but mostly the lousy quality of the wood used. The kind of wood was the same it had been used for centuries, but the quality degraded to incredible levels. Around those years I sailed a traditional boat , a 60 year old wooden boat recovered and modified by me, and I found out that the original wood seemed to last forever, but the pieces that were substituted only lasted 5 or six years. The wood was from the same tree, (Pinheiro Bravo), but the quality was not the same. The problem was that boatyards were using the same wood that was used in the house building construction, wood that was inexpensive but not specifically prepared for the boat building, as it had been before, for hundreds of years, and that had made all the difference. The main difference is that modern pine wood has no resin in it, or very little. The resin is taken away from the tree by several processes and that weakens greatly the sea resistance of the wood. Of course, you can not work the wood full of resin, so they use to put the logs in mud for several years (in ancient times, many years), to dilute the resin prior to work the logs. So, Guillermo, I have no difficulty in believing that the Eucaliptus wood, treated and grown in a different way can be very different from the bad Eucaliptus wood that I know. Quote:
What do you mean by that? Our king D. Dinis, named “The Farmer” ordered that all the sandy coast line be populated by huge forests of Pine trees (Pinheiros bravos) as a way of protecting the land from the sands. This was on the XIII century, way before the significant Naval construction of the XVI century. The Pinheiro Bravo was a native tree, from here and from vast regions of the Mediterranean (the south of Portugal has a Mediterranean climate and lots of species in common with that region.) Quote:
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#3
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On top of this, if the wood has not been properly treated (correct time of year to abate the tree and then the proper method and time of drying it out), you get the kind of problems you mention. I've even seen 'pinheiro bravo' plankings rotting in a couple of years. But let's do not blame this tree: If wood is properly treated and boat maintenace properly done, you can get many years of satisfactory life for it. Quote:
The use of leaving the trees for a long time in a muddy beach brings to a substitution of the remaining sap for minerals , thus 'mineralizing' the wood and making it more resistant to rot. I've seen this method still being used at the 'Castro' boatyard in Camposancos, spanish side of the Minho river mouth. Drying methods, both natural or forced, do not take the sap from the wood, just the water. Chemical treatments provide increased resistance to rotting and insects attacks by impregnating sap channels with the adecuate chemical products. Quote:
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Just to end, a quote from the 'Livro Primeiro da Architectura Naval' de João Baptista Lavanha (End of XVI, beginning of XVII): 'E começando das Madeiras; se em uma Taboa dellas està a salvação dos Navegantes, e só dous dedos da sua grossura se mete entre elles, e a morte...' Cheers. Last edited by Guillermo : 02-27-2006 at 11:11 PM. |
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#4
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| There is a publication called Timber in Australia, Timbers of Australia - something like that Two volumes, now out of print, but often available from libraries. If you want to email me in about ten days I will be in a place with a copy so if you would like to email me directly at that time I will check for you. storerm@ozemail.com.au. The book has a trememdous amount of detail - hardness, gluability, what angle a plane blade should be bevelled at for most efficient cutting etc etc etc. Are you looking at a traditional construction boat - no glue or modern construction - glued? Where in the boat? There are mentions here but not much use. http://www.rainforestinfo.org.au/good_wood/oz_pln.htm http://www.boral.com.au/Article/Timb...timberflooring http://www.forest-network.org/GoodWo...e/GWG2.htm#ant Or post the question HERE in the boating forums - there are some old timers around who know this sort of stuff. http://www.woodworkforums.ubeaut.com.au
__________________ my boat pages |
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#5
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| Thanks a lot, Mike, More interesting information on eucaliptus: http://www.tastimber.tas.gov.au/spec...fs/bluegum.pdf http://wwwlibrary.csustan.edu/bsantos/euctoc.htm#toc http://www.cismadera.com/downloads/art9.pdf (In spanish) I'm looking for info on both traditional and modern techniques. In Galicia we use Blue Gum for traditional boatbuilding, mainly for long longitudinal members and big deck beams. Rarely as hull's planking. I've supervised the building of an small rowing boat, entirely built with Blue Gum, using laminated frames and strip planking for the hull, as an experiment at a wooden boatbuilding school. Nice result although pretty heavy, as expected. I'm trying to convince the boatyards to substitute the Oak frames (everyday more difficult to find the proper wood) by laminated Blue Gum frames, and so I would like to gather as much information as possible on boatbuilding with this wood. I've posted the question at Woodwork forums, as you suggest, and I'll write you in ten days. Thanks a lot again. Cheers |
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#6
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| blue gum Re question suitability of blue gum for boat building,I am not familiar with the latin name ,so not sure whether your blue gum is the same as here (Australia) However southern blue gum is native to Tasmania and Victoria and was widely used in boat construction.there are many types of gum (eucalypt) used here in boat building .unfortunately not so much now,these are river red gum forrest red gum ,spotted gum,flooded gum,grey gum, rose gum,and so on I would suggest any old growth timber from the above will make excellent boat timber ,having regard to the type of craft,none of the above is a light weight timber ....cheers |
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#7
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Any special reason for this decaying use of eucalypt wood for boatbuilding nowadays? Cheers |
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#8
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Gilly mate your doing it again, just as I start to like you and think your not a bad chap for a member of the 'intelligentsa' you come out with a complete load of supercilcious claptrap in a most condescending manner - it can be really annoying - who do you think you are - ME!? ![]() |
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#9
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| blue gum Hi Guillermo re reasons for declining use of these timbers ,firstly wooden boat building here is about as dead as the dodo(flightless bird I think) secondly ,add land clearing,and to our eternal shame ,wood chipping whereby whole old growth forests were cleared and the wood chips sent to japan ,progress I suppose ......cheers |
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#10
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| I use blue gum for samson posts, also just put in blue gum headlining over jarrah beams to deckhouse & trunk cab on 40' cruiser rebuild-looks nice.Regards from Jeff. |
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#11
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I do not pretend to be condescendent nor overprided at all, and I think I'm not. Maybe it's your grumpy character, prejudices or understanding of my poor english, sorry. By the way, May I know your real name? |
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#12
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| Gilly I did not mean that the methods used by old boat builders should stay the same more that because of several different things (age and experience) your average long term boatbuilder (not unlike ANY older person) would take exception to someone who ostensibly appears 'better' than them (or more to the point thinks they are) no matter what the subject!! Getting people to change is an extremely hard thing to do, no matter the reason! we have a saying "you can't teach old dogs new tricks" to cover this! You do appear to have a way that seems to inflict this on many people - so maybe it's your way - same as what I do is my way! Rubs a few up the wrong way but generally works for someone! Mike (the Walrus) |
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#13
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Maybe we have a problem in this forums about everyone writting english but not all knowing it with the same deepness and some of us having difficulties to properly express ourselves in a not well known language and understand some of the expressions, as well as we have different cultures and ways of thinking and feeling. Maybe what it is to me an innocent joke or plain observation maybe an insult to you, and viceversa. I have lived in Mexico and Portugal for around seven years in each, and, believe me, although in México they speak Spanish, and Portuguese is very close to Galego (my homeland language, so I speak a quite fluent portuguese), I've learnt that I had to be very careful because there are many words meaning exactly the contrary of what is their meaning for me, and the sense of humour is quite different for some aspects of life. And, on top of this, it is not the same to talk face to face than doing it in written. We cannot properly transmit feelings, even with the help of emoticons. Maybe we should be more cautious about what we put in written in a forum like this.... Quote:
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#14
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Whilst I know I tend to play 'devils advocate' on a regular basis, I firmly believe that without this a false sense of 'bonhom' would endure that could lead to death! Rather to be hated and abused than see somebody die for want of a precautionary word, and with this in mind 'if somebody has a 'go' at me I will certainly respond in a like manner, until either I get my point across (Not to bothered about winning, just getting the point across!) or it gets to far in which case I shall cut them dead! sorry to be to heavy Gilly, and most of this is not actually aimed at you, but that's the way I am! (actually I do enjoy our little spats, you argue with conviction and knowledge, mostly!) ![]() |
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#15
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| Oh and Gilly, hope you had a good St. Pirans day - we did of course! That'll get them as don't know eh! ![]() |
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