Blue Gum as boatbuilding wood

[Vega]

Originally Posted by safewalrus

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!
Mike (the Walrus)

Mike the Walrus, I like that ...about what you have said, I had an experience that I think is exemplar of what you and Guillermo are talking about:

Almost 30 years ago I have bought a very beautiful and old traditional wooden sailing boat that needed a full restoration.
I did not have the money to have the job done professionally and I did not know anything about it. I began to collect as much information as I could about modern wood treatment technologies and for that I have written to International and Hempel, asking for advice and information on their new products (internet and this forum would have been handy then).
I have received from Hempel a very good and detailed information, not only about their products but about wood and new technologies, so I have started using them.
At that time, Peniche had a lot of wood shipyards and a wealthy nautical industry. People worked and built the boats outside the sheds, where the machines operated. So I asked permission and just put my boat in the middle of the others and started to work.

Of course I was the laughing stock of all those guys, (I was then a teacher in town) but obviously my hands were incredible stupid and the least bright of them had smarter hands than mine.
In the end I was kind of adopted by the carpenters, they told me how to do everything and even have done for me what I was not able to do.

But when I started to apply all those new products (all two components wood sealants, fillers, primaries and paints) they scratched their heads and took a good look at it and started to come and see what was happening.
They started to use in their work the two component filler I was using, and when I asked why they would not use the wood sealant and the other stuff, they laughed at me and said: Paulo, If we use all that stuff, the boats will need so little maintenance that we will not have enough work.

Of course, now they are all out of work and there are no more wood boatyards in Peniche...boats now are made of steel or fiberglass, because they need less maintenance…

So, I guess, changing is a survival question in the wooden boat industry...and if the changing goes in the right direction, I believe that traditional wooden boatbuilding has a future, even if it will not be so traditional as in the old times

[sailsnail]

Que tal Guillermo,

Blue Gum is a common name for many different species of Eucalyptus and as has been said many of them will be suitable. I think that although 40 yr old timber will not be the same quality as oldgrowth, it will still be suitable. But... the problem, as you said, is with the seasoning process. The 'people' who harvest it and get it to the end user are supplying a different market today, they have to keep their sawmills running so they harvest all year round, and the income from one load finances the harvest of the next load. They don't have the time/resources to have it lying in the mud for five years.

If you are serious about that kind of quality then you will have to do it yourself. There used to be a product called PYE (I think it was made by Shell) that mineralized cellulose mollecules but I haven't seen it for 30 years now (maybe it has a new branded name?). It was not cheap and therefore probably not cost effective. It was used mostly to treat mine props and I know this because I used to sell Eucalyptus grandis props to the mines in South Africa.

Now, wallrusses on the other hand, are easy to harvest, they debark well and you can season them with salt and....

Un Saludo!

|>

[Guillermo]

Gracias, Sailsnail.
¡Un saludo para ti también!

Mike the Walrus,
I'm not pretending to make you change at all, absolutely!
As you said: 'Getting people to change is an extremely hard thing to do, no matter the reason!'

[Guillermo]

Originally Posted by Vega

..Of course, now they are all out of work and there are no more wood boatyards in Peniche...boats now are made of steel or fiberglass, because they need less maintenance…

Yeap! A pity.
Anyhow they do build nice boats in Peniche nowadays, like the ferry in the attached image, done by a Galician NA I know... (the image, not the boat!)

[Guillermo]

But they still build in wood!
http://www.enp.pt/

[Vega]

Originally Posted by Guillermo

But they still build in wood!

Well, what I can say to you is that there is not any wooden boat being built at Peniche. The photos are old. They still have some carpenters because we still have old wooden fishing boats working and needing repairs, but regarding new boats, it's finished.

[Guillermo]

Paulo,
One leading Galician wooden boatyard is building now 18-22 m fishing boats with structure in eucalyptus (longitudinals and beams) and french oak (transverse), as almost everybody around here, but hull skin is partly carvel planked and partly in marine plywood in two epoxied layers of 20 mm each. Decks are also marine plywood as before. They look great and are very stiff.

Increasing experiences have been carried since 6 years now, with excellent results, requiring very low maintenance. Next step will be doing the whole hull skin in plywood, probably using three layers instead of two.

We are studying several alternatives for the structure, maybe substituting the oak also for eucaliptus and even changing to a whole eucaliptus laminated one (That's why I'm gathering information on eucaliptus boatbuilding). But laminated elements, having smaller scantlings, will change the masses and inertias distribution, so changing sea behaviour, which fishermen don't like (That's the reason they don't like either GRP for rounded hulls).

So it would be necessary to keep scantlings as for carvel construction, which doesn't make a lot sense. The evident possibility of changing hull forms is a difficult decission, as fishermen do love traditional looking boats and their nice movements at sea, as said before.

Working on that...

Anybody in this Forums has already dealt with this wood fishing boats issue too?

[Vega]

Originally Posted by Guillermo

One leading Galician wooden boatyard is building now 18-22 m fishing boats with structure in eucalyptus (longitudinals and beams) and french oak (transverse), as almost everybody around here, but hull skin is partly carvel planked and partly in marine plywood in two epoxied layers of 20 mm each. Decks are also marine plywood as before. They look great and are very stiff.

Happy to know that in Galicia there are boatyards that are trying to use wood in innovative ways (and looks like you are one of the guys that are making the search - congratulations Guillermo).I hope that those involved in this venture can succeed commercially.

Wood is an easily workable material (and agreeable too) that can be worked to almost any shape, permitting great flexibility.

Have you ever considered the use of a wood traditional frame and instead of wood or plywood, strongplank for the skin and then fiberglass over it? It would result in a very strong boat, and the strongplank is almost as versatile as wood in what concerns shapes.

About Oak:

Last weekend I met some old salts in Nazaré ( +70 years), they had done everything from fishing to boat construction. I found them because someone has said to me that one of them (a former naval carpenter) was building some very perfect scaled down replicas of old traditional sailing boats.

The boats were beautiful (I have made a command for one) and then we were having a nice chat about the old days of sailing fishing boats and wood construction when another "senior" salt came who in is youth (before his fisherman days, 65 years ago) had also been an apprentice carpenter.

He has told me something that I have never heard before. He said that his old boss used to make them put huge quantities of salt over the planks of sobreiro (cork tree), that as you know is a variety of oak. The salt was put in big sacks with holes and left over the planks for several months, thus mineralizing the wood (with the help of rain water). He claims that after that treatment the wood was a lot less prone to open cracks (the biggest problem of oak woods), in his words, "the wood became smooth as skin".

Do you ever heard about it?

[BOATMIK]

Originally Posted by Guillermo

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.

As promised Guillermo!

Finally grabbed the book and typed up the entry for E. globulus

Hope this helps.

I think what you are doing is great. Everyone has to work together to hold onto what little is left of the wooden boatbuilding/shipbuilding tradition - if people want to become master shipwrights that is good and fine, but a lot of the information - particularly geographical differences can only be protected through amateur and academic interest - not to mention that from NAs.

For example the information below comes from Australia, applying to Australian wood in Europe. This is the way things will be happening from now on.

Despite his recanting I think Walrus was way off line with his initial comments - work to bring information that will support wooden boatbuilding is laudable.

Anyway - here is the reference I promised

Wood In Australia
Keith R Bootle
(out of print but highly useful as it contains most Australian timbers and most significant imported timbers)

Southern Blue Gum - E. globulus

1/ Larger hardwoods of the cooler districts of SE Australia mainly in Victoria and Tasmania. Has been planted in many countries overseas. Leaves are rich in eucalyptus oil.

2/ Heartwood pale brown, sometimes with a pinkish tinge. Sapwood to 50mm wide, paler but not always sharply distinguised from the haeatwood. Texture medium and relatively even. Grain often interlocked. Growth rings prominent on end section.

3/ Green Density - between 11-- to 1200kg/m^3, Air dried density 900kg/m^3

4/ Needs care in drying to minise checking of hte tangential surface. Quarter cutting is desirable. Considerable collapse can occour. Shrinkage about 6% radial, 12% tangential

5/ Satisfactory for steam bending if carfully selected for straightness of grain.

6/ Heartwood moderately durable (class 3). Sapwood sisceptible to lyctid borer attack

7/ Structural information - first figure on each line is green timber, second one is air dried.
Modulus of rupture MPa - 78 146
E GPa - 11 20
Max crushing strength MPa - 40 83
Impact (Izod) Joule - 16 23
Hardness (Janka) KN - 7.3 12

[BOATMIK]

Some follow up information

Spoke to Ted Dexter at Duck Flat Wooden Boats who has extensive knowledge of forestry and plant species.

He mentioned that you have to be careful with Southern Blue Gum with regard to growing conditions. In many places it is used in sewage treatment so is used to soak up excessive amounts of both nutrients and water.

The end result is that it grows extremely quickly resulting in a wide spacing in the grain structure. The drop in density caused by this quick growth will change everything in the above article and also increase the probability of serious flaws in the timber structure.

To get the excellent mechanical properties of the native Australian timber it needs to be slow grown with low levels of moisture input. The way to tell will be to check the density against the info in the post above.

If the density is similar - it is probably OK - and if there are problems the shipwrights would have noticed them and should be warned to be aware of the possibility.

If the density is substantially different from the above post the timber really needs to be reassessed from scratch as none of the other properties will necessarily apply.

Best Regards
Michael Storer

[Guillermo]

Thanks a lot, Michael and Paulo, for your help.

Paulo:
I didn't know about the 'salt' method of mineralizing wood! Most interesting! I'm gonna ask my 'old boatwright chaps' to find out if they know something.

Strongplank is used for strip planking technique, wich is not the best for our purposes. Requires a lot of hours of manwork and tensions induced by temperature changes in bigger hulls, through their lives, are quite important. I've tried this for an small traditional galician boat (http://www.gestenaval.com/bote_aixola.htm) and afterwards discussed the method with some boatwrights. The conclusion was that they rather prefer cold molding over traditional structure, as it is easier and quicker to work with, and leads to stronger hulls, less prone to damage and easier to repair.

Maybe you are interested in visiting also:
http://www.gestenaval.com/carpinteria_ribera.htm


Michael:

Thank you very much for your very kind help.

I agree eucalyptus grown on very humid locations do not produce good wood.

Eucalyptus is prone to have quite important 'growing tensions' which lead to fences when abating the trees. This is specially relevant when farmed in very high density (As to get wood for paper paste, i.e.). To get a nice wood, plantations should have no more than 135-150 individuals per every 10.000 sqm. This minimizes the growing tensions.

In Galicia we have developed a quite simple method of abating trees to further reduce tensions, that consists in peeling off a perimetral ring of 2 cm depth at the base of the tree, two months prior to its abatement. This makes the tree to lose 'strength' and tensions are minimized.

Afterwards, a very precise method of sawing the logs is applied, also to further avoiding fences.

Properly drying out is then needed, be it natural drying or, even better, forced drying under precise control (You don't have to wait a couple of years).

All this procuces wood of excellent quality.

There is a very interesting paper on eucalyptus at:

http://wwwlibrary.csustan.edu/bsantos/euctoc.htm#toc

Cheers

[Guillermo]

For those of you who understand spanish:
http://www.xornal.com/article.php3?sid=20050526132526