Okume or not?

[flydog]

Going to build a lapstrake sailing dingy from plywood. Choice of wood here in Atlanta are few. Either 3 ply AA fir, or okume. I was thinking of using the okume with an epoxy saturation because of its low durability and rot resistance. Any comments would be helpful. Thanks!

[lewisboats]

lots of boats are built that way. It is a proven method.

Steve

[Chris Ostlind]

Flydog,

When you say saturation, what exactly are you describing?

Chris

[flydog]

The saturation technique is to basically use a low viscosity epoxy that wets and soaks in the wood to preserve it.

Steve

[Chris Ostlind]

Flydog,

I'm not trying to be a hair splitting weenie on this subject, but every time I hear the saturate term used for the painting-on of epoxy to the surface of a plywood hull in construction... I get this picture of huge amounts of epoxy being used to totally flood the wood to its capacity to carry fluid. I picture a sponge floating in a sink full of water until it is so full, it can't absorb another drop

Sicne that isn't really happening at all, I wonder if there isn't a better term for the process of pre-wetting the surface so that the cloth is not resin starved once the glass laminate is applied?

A truly saturated wood core would weigh hundreds of pounds more than planned and seriously effect the displacement potential of the boat and its carrying capacity.

Chris

[JR-Shine]

Okoume will soak in a little epoxy (thin laminating epoxy), My guess would be around 3-4 oz. (weight) per square yard. Its not very much. "Encapsulation" is what your after.

[PAR]

I'm going to chime in because an often over looked aspect to epoxy encapsulation (the only true way to seal out moisture) is the additional cost, materials and effort it can place on a project.

Penetrating epoxy will soak in quite well. Laminating epoxy, if particularly thin or heated (or both) will do almost as well.

A traditional lapstrake dinghy is a wonderful project. The challenges to the builders skills can be rewarding (and frustrating), but the result is a beautiful set of sweeping laps that add a touch of grace and style to an other wise bland hull. It's one of the more difficult building methods and repairs are equally difficult, but the results speak volumes.

An epoxy version of the same craft can double it's costs, when you count the additional effort and materials. I sometimes find it had to justify these costs in time and materials. Of course glued lapstrake construction couldn't be without plywood and epoxy, but that's a different animal. On larger craft, epoxy can have a place, but in smaller boats I have problems with explaining it's use.

Shaving up the laps on a cedar sailor is very enjoyable. Chasing drips, scrapping excess, filling weave, fairing, filling, filleting, messing with goo, trying to get it on the work before it smokes in the pot, etc. isn't my idea of enjoyment in small craft construction. I've repaired many lapped craft and have found the epoxy ones didn't last any longer then the well care for traditional versions of the same.

For what it's worth . . .

[catsketcher]

My two cents worth is that Okume (we call it Gaboon in Australia) is a rainforest timber and that most of this timber is not sustainably logged. I love sailing to great places and feel it is incumbent on us to make our boats out of materials that don't degrade beautiful spots somewhere else in the world.

Plantation fir will make a great boat that is a little heavier. I use plantation Hoop Pine in my catamarans and they work very well. It is 530kg/m so I am a little heavier but the extra weight does give you extra strength so you can reduce some scantlings a little.

cheers

Phil

[Raggi_Thor]

I am ambiguous (do you say that) regarding sustainable woods, rain forests etc.
When we buy okume, maybe most of the money end up in some french pockets, but some of it also go to the workers in Gabon. They certainly need it. We (Norwegians) cut down all our pine woods and sold it to the Dutch and British a few hundred years ago. Now we are not willing to let 1% of the forests be untouched here. Is it fair that we ask poor people in Africa to let their forests be untouched?

[lewisboats]

I am ambiguous (do you say that) regarding sustainable woods, rain forests etc.
When we buy okume, maybe most of the money end up in some french pockets, but some of it also go to the workers in Gabon. They certainly need it. We (Norwegians) cut down all our pine woods and sold it to the Dutch and British a few hundred years ago. Now we are not willing to let 1% of the forests be untouched here. Is it fair that we ask poor people in Africa to let their forests be untouched?

Ambivalent is the word you are looking for. Means neither here nor there...of no specific opinion pro or con. I tend to take the same road. I don't particularly like the idea of stripping the rain forests and jungles but the ply I can lay my hands on is Crap otherwise. I wish there was a way of farming the most useful stuff instead of raping the natural sources.

Steve

[hansp77]

I don't think there is much of an argument for providing income for the locals.

ignoring the ecological perspective (or critique),
If the forestry companies were community owned and the money earned actually went into providing real assets and security (for the biophysical ones they are removing) then that may well be the case (and could be in particular places).
But most of the global timber industry is far from that.
Often getting considerable government subsidies and inducments, with rediculously cheap access to land, the actual benefits from the deforestation spread very thin through the comminity/economy/nation compared to the irreplaceable natural assets that are removed.

The timber industies are masters at influencing government policy and public opinion on how beneficial its practices are to communities/regions/nations. They often blame environmentalists and conservation efforts for taking away jobs and destroying communities- yet every chance they get to introduce a new technology that will reduce labour time and workforce size they leap at.
And then what do they do when the forests are gone?

I am not saying that we shouldn't cut down trees. But the way these guys are doing it- its a fire sale.
In rich developed countries with established conservation politics this occurs-
it third world or developing countries it is just that much easier to trully exploit the situation.

That said, I used pacific maple (meranti) marine ply on my boat.
It was about the only suitable thing I could get and or afford at the time, and I needed it too fast to hunt around.
I feel a bit guilty about that. Next time I will try to be more aware.

It is just a shame that we can't be a bit more precautionary and considered on our forest harvesting.
If we only harvested forests at the rate that they grow (from memory about 3-4% p/a ?) then we could have our cake and eat it too.
Instead it makes better economical sense to clear-fell entire regions and invest the money where it will grow at over 10% p/a.

I can't escape the feeling that the way we go about forestry is like somone walking into a new car lot and melting down the lot to sell as scrap metal.

These things and their ecosystems have a much higher value than we are ascribing them.

Enough of a rant from me.

I love trees,
but I also love timber...

[Crag Cay]

I think there are very valid reasons to be concerned about the use of tropical hardwoods. Apart from any ecological problems (and I'm in no way belittling these), the sale of plundered forest products is, along with diamonds and other commodities, frequently used to prop up several unsavoury regimes and fund protracted wars. The 'Geographical' magazine found much of this timber was corruptly passed off as 'from sustainable sources' and traced it to several wood yards in the UK.

Whilst the boat building use is only minor compared to construction or outdoor furniture, I feel it is incumbent on us to be careful. I don't spec any tropical hardwoods for the interior of boats and restrict its use elsewhere to the absolute minimum. I have found that the 'teak substitutes' for decking, (preferably the cork based ones), are more than acceptable in durability and appearance.

[Jimbo1490]

The world has been, on the whole RE-foresting for over a century now. The real reason forests get cut down (and not allowed to re-grow) is to create arable farm land. Modern farming methods have increased the yield of farmland so dramatically that year after year more farm land is idled and returns to forest. Re-foresting takes only 50-70 years, NOT 1000's of years as many green whackos would have you believe.

Now the same green whackos have been pushing for decades to limit, curtail and eventually ban the modern farming methods. We can probably afford to do that in North America and Western Europe, for we are relatively wealthy. But what about the developing world? Without modern farming methods, crop yields will be much lower, with the resulting pressure on forests returning.

Read Bjorn Lomborgs books! He is the man!

Jimbo

[Chris Ostlind]

So, Jimbo...

Would it also be fair to refer to anyone not concerned with the environment as an Industrial Whacko?

Come on, man, you can do better than that when you communicate.

There are salient points on both sides of the issue. To ignore one side in favor of the other, simply because you like the rhetoric and tag lines, is more than insincere, it borders on the foolish.

We get one little blue ball to play with. When that is done, so is everything we cherish not to mention desperately need for the essence of life. Manage it well, be responsible to future generations and be respectful of those who have different ideas.

And no, I'm not a Green Whacko, to use your terms.

[mulletbucket]

To answer the question about okume. Yes use it, we've used it here in North Carolina on our custom boats for some time with no problems. Be sure to buy standard 1088.

[Jimbo1490]

I refer to them as 'whackos' since their positions are generally without merit. For instance it makes no sense whatsoever to curtail an activity, modern farming in this case, that is constructive for what they claim is their cause, preserving forests and 'green space'. Yet that is exactly what they do. The alternative that they suggest to the poor of the less developed nations is basically "Go ahead starve, since there are too many of you anyway, and we educated people of European descent are more important than you, therefore we choose not to starve"

If my words sound like hyperbole to you Chris, then you may be a little ignorant of the environmental movement, because they actually do hold positions similar to this.

I was one of them once. I was a member of Greenpeace. Then my research did me in. I found that the environmental movement is really NOTHING MORE THAN a political movementthat that uses junk science as a motivator. This is no less feckless than certain politicians who use "National Security" as a scaremongering motivator. It's exactly the same thing. As such lies and exaggerations are an integral part of their M.O.

Again I urge you and everyone to read Bjorn Lomborgs books and get the FACTS!

Jimbo

[Raggi_Thor]

To the original topic: use okume, it's light and won't cheek.

When it comes to morale and politics there are many questions, for example:
Should Africa be a natural park or is it OK to make it into farmland and plantation forests?
Is the use of wood in boats a driving force in deforesting?
I suppose it's not.

[Chris Ostlind]

Quote from Jimbo:

Again I urge you and everyone to read Bjorn Lomborg's books and get the FACTS!

The subtext here, being... Bjorn's facts.

I can't help but be more than a little reminded of the eerily similar claims by the Scientology community with regards to the writings of L. Ron Hubbard.

Facts are transitory. Hell, even science is transitory, so the facts produced by science are always in a state of flux. We know what we know... Right Now. Tomorrow...? that's another discovery process. Why should Bjorn's particular brand of facts be any different.

Yes, there is hyperbole on both sides of the argument (though I did not intimate that you were spewing hyperbole yourself). You get that sort of polarization whenever two disparate groups attempt to override each other with message laden campaigns. Reality be damned, it would seem.

I just suggested that you could do better than resort to sloganeering in your argument. Judging by your use of the available vocabulary in the second letter, it would appear that I got that right. The trouble with slogans is that they really don't communicate the specifics of the moment, Oh, they sound snappy and they provide good TV bites, but they never reflect the true essence of what folks are experiencing on a personal level.

This is, as you have so eloquently indicated, a very complex topic. I'd love to hear more of your thoughts on the issues. Is it possible to refrain from the confrontational personalization aspects and hot-pack rhetoric that only take the discourse off-topic?

[Jimbo1490]

We should probably take this discussion to a more appropriate venue than the "Wooden Boatbuilding and Construction, topic: Okume or not?", don't you think? Move it over to general?

Jimbo

[timgoz]

Jimbo,

The above (from Chris) is good advice. It's all not "Black & White". No individual has it all figured out. When a Greenpeace member, did you not feel you where right? Now after further mental input, the pendulum has swung.

I have ideas & opinions that could be considered from either camp. That does not make me neither traitor to, or member of, either.

There are as many combinations of opinion, as there are people who take the time and effort to form them.

Tolerence of those you disagree with & proper manners will go along way on this forum.

Take care.

TGoz

[Jimbo1490]

DO take the time to Google on Bjorn Lomborg and see what you get. He is not a scientist or environmental activist. He is a university professor and economist who assigned his class the task of accumulating all the data they could from all of the sources they could find which supported the 'doom and gloom' claims of environmentalists. At that time he, as well as his students and most of the rest of us, I dare say, believed those claims completely. To their complete suprise, they found virtually no foundation for the belief that our natural environment is in a teririble state, or even in a deteriorating state. This was such a revelation that he decided to do further study and publish the results. His book "The Skeptical Environmentalist" was the result.

http://www.lomborg.com/

So this is not about a moving set of 'facts' but about one side, the environmentalists using 'junk science' tactics, like spewing exaggerations, known obsolete data and even outright lies and cooked numbers to scare people and get votes. Why? Because, as I've said, it's a political movement and politics is the struggle for power.

And nobody bothers to question their assertions, no matter how absurd! Some guy makes a statement that a certain trimaran can plane its main hull and some people take STRONG exception and say "prove it!" It's not wrong to ask for the same rigor when discussing matters of far greater import, is it?

If you want specifics, there are plenty and I can give you many. But again, this is only slightly about Okume and boatbuilding anymore, so a move to the general discussion area seems appropriate, agreed?

Jimbo

[Chris Ostlind]

I'll be happy to follow your comments to the new location.

Chris

[D'ARTOIS]

The Ocumea kleiana is commonly used for the production of top quality plywood.
It is one of the best substitutes for Mahogany, the Swietenia, that is originally found in Central-America and the northern part of the South American continent.
There is a variety found in Brazil that is called "Abarco" - Okoume is class II hardwood, 0.65 spec. grav. - agai, widely used for marine grade plywood.

The wood itself comes from West-Africa, not specifically from Gabon, however, due to the continuing conflicts in that area, this wood will very soon be exterminated. Just like in Mocambique, Angola and frankly, most of the African countries, regardless cutting of tropical forests which is now common practice, will make soon an end on the exports of African hardwood.

Specifically China, with it's upcoming yachtbuilding industry, is desperate for these kind of woods and they have plenty of hardware available to pay for it, if you know what I mean...

[ancient kayaker]

I agree with PAR on the undesirability of epoxy coatings. It should not be necessary on a small boat that does not get too much punishment and does not stay in the water for long periods. I do not even use epoxy as glue. Since this thread has become an environmental one, what do you guys think about the environmental impact of epoxy, and glass fiber as well? My boat may not last as long with its simple paint job but at least it will rot decently when it dies.

[Raggi_Thor]

I don't think small boats matter much for the environment compared to for example the (house)building industry or transportation.

A boat covered with epoxy and polyurethane paint may need less chemicals for upkeep than a traditionally treated wooden boat.
Is tar and linseed oil good for the environment?
Just because it's more "natural" doesn't mean it's healthier.

[catsketcher]

Jimbo,

As one who may have kicked off the ecological debate I feel the urge to respond. To portray all people who like to care for the planet as whackos is wrong and dangerous. No one person, even the person you refer to has the "correct" view on this.

To my mind history itself is the best teacher. Woods my father used - Australian Red Cedar (Toona Australis) and Huon Pine are not available for me to use as there are no logs to be found. Huon takes up to a thousand years to grow. Red cedar needs a a lot of decades and doesn't like plantations. Obviously the take it all approach of our fathers has left us poorer. I do not want to repeat their mistakes either in my own country or others.

Look the only thing a greenie can really do is jump into a void and hope that you don't rot and give off greenhouse gases. You have to tread as lightly as you can. For me that is using plantation timbers - Hoop Pine ply and Kiri or Foam for cores. There are problems with this approach but it is one I feel is reasonable. Epoxy for all its problems allows the use of inferior timbers so its use can be a benefit for the environment.

cheers

Phil Thompson

[ancient kayaker]

Raggi_Thor: tar and linseed oil are probably ecologically sound, at least the tree-originated tar, but I just use exterior acrylic house paint. I try to be good but I'm not a saint! I'm told I can put linseed oil on the inside but I haven't tried that. Catsketcher: good point about using inferior wood, I've been using household ply instead of marine ply for the skin. I ecently changed from clear red cedar to pine for the rest, I am regretting it. I would love to get decent timber as it is grown, maybe; maybe not as its a lot of work. The environment is complex and we can only do the best we can for it. My way is to minimize epoxy but I don't know if Acrylic will do the decent thing and rot, either.