I've just got a quote back from a company on planking stock. The
White Oak came in at around £20 cheaper (negligible) and therefore
price is not a consideration. The HMSO Handbooks of Hard and Soft
woods make the White Oak sound like a very good material, particularly
with regard to bending with a downside of a tendency to dull tools and
variability in quality dependant on the precise species and
environment. It made the Cedar out to be a rather brittle material,
although easy to work, although no precise mechanical properties are
available in my edition (1957 reprinted '60).

Appearance is a secondary consideration to strength in this
application and ease of working. Which would you consider to be the
better timber to use for a 9foot stem dinghy expected to last a while,
given that this is my first foray into traditional construction?

I would also be grateful if suggestions could be made about suitable
centreline materials, again, strength and suitability being primary to
appearance. Leather suggests a mixture of Mahogany (Utile is
available), Iroko or Oak in his book "Clinker Boatbuilding" but I'd be
interested in other's opinions.

Thanks for your time and suggestions.

Al

On 19 Sep 2003 09:54:27 -0700, (Al) wrote:

Which would you consider to be the
better timber to use for a 9foot stem dinghy expected to last a while,
given that this is my first foray into traditional construction?

I would also be grateful if suggestions could be made about suitable
centreline materials, again, strength and suitability being primary to
appearance. Leather suggests a mixture of Mahogany (Utile is
available), Iroko or Oak in his book "Clinker Boatbuilding" but I'd be
interested in other's opinions.

You are on the right track. Keel and stem of white oak. Planking of
red cedar. Red cedar is somewhat brittle in its mechanical properties,
that is true, but it was the commonly used planking stock for small
boats.

Wood should be air-dried. Kiln dried is much more brittle. If at all
possible you should get green white oak for your frames.

Small boats do tend to be more "bendy" than somewhat larger ones.
You can't reduce beam as much as length in a small boat. Thus, the
planks are bent somewhat more. It could be said that a dinghy is a bit
more difficult to build than a somewhat larger boat, say in the 12 to
14 ft. range. If possible, I'd build a bit larger boat; it'll be more
usefull as well.

I know that white oak used to be used sometimes for planking in Scandanavian
clinker construction, and made for hell-for-stout but heavy hulls. It would
make for a rather heavy dinghy, and the planks would likely require steam
bending at least at the bow. You might consider Alaskan yellow cedar for the
planking; it's light and strong, and I wouldn't call it brittle. Port Orford
cedar, if available to you, tends to split lengthwise down a considerable
length of the plank if something happens to it to cause it to split, but
Alaskan yellow has more interlocked grain and damage remains more localized.
White oak is great for the keel timbers and stem, green white oak if
carefully chosen for clearness and grain runout would steam-bend quite well
for the frames. Another good choice for the steam-bent frames is locust. In
your dreams, you'd find a white oak natural crook for the stem and transom
knees. White oak, on the other hand, doesn't like being wet all the time,
and a keel of white oak might take some damage from rot if water is left in
the bottom of the boat a lot. A superb keel timber is purpleheart, but it's
extremely difficult to work with hand tools and even heavier than white oak.
Some folks like to get out the sheer strake from Honduras mahogany, both for
strength and for appearance. Mahogany is also a good choice for the transom
and transom framing, the stringers for the thwarts, and the thwarts
themselves. Teak floorboards, perhaps 5/16" thick in order to take the
slight bend, could be left altogether unfinished so as not to be slippery
when wet, but would not deteriorate from exposure to weather. If you should
use mahogany for the sheer strake, you may have to steam-bend the part of
the plank that takes the bend at the bow. By the way, avoid so-called
Philippine mahogany - it's not a true mahogany but actually a type of
tropical cedar and is a totally inferior boat building wood.

As to white oak species, as I've sometimes heard said, "White oak seems to
grow on a lot of different kinds of stumps." The species you're after is
quercus alba.

Hope this helps,
Tom Dacon

"Al" wrote in message
om...
I've just got a quote back from a company on planking stock. The
White Oak came in at around £20 cheaper (negligible) and therefore
price is not a consideration. The HMSO Handbooks of Hard and Soft
woods make the White Oak sound like a very good material, particularly
with regard to bending with a downside of a tendency to dull tools and
variability in quality dependant on the precise species and
environment. It made the Cedar out to be a rather brittle material,
although easy to work, although no precise mechanical properties are
available in my edition (1957 reprinted '60).

Appearance is a secondary consideration to strength in this
application and ease of working. Which would you consider to be the
better timber to use for a 9foot stem dinghy expected to last a while,
given that this is my first foray into traditional construction?

I would also be grateful if suggestions could be made about suitable
centreline materials, again, strength and suitability being primary to
appearance. Leather suggests a mixture of Mahogany (Utile is
available), Iroko or Oak in his book "Clinker Boatbuilding" but I'd be
interested in other's opinions.

Thanks for your time and suggestions.

Al

Nobody mentioned it, so I will. If you are using epoxy, be aware that white
oak can sometimes work, sometimes not. I've heard a lot of arguments as to
why, but I've not seen a lot of answers for how to guarantee that epoxy will
stick to white oak as well as it sticks to other types of woods. White oak
is more rot resistant than red, so don't be tempted to use red oak because
it glues better.

Brian

--
My boat project: http://www.advantagecomposites.com/tongass


"Al" wrote in message
om...
I've just got a quote back from a company on planking stock. The
White Oak came in at around £20 cheaper (negligible) and therefore
price is not a consideration. The HMSO Handbooks of Hard and Soft
woods make the White Oak sound like a very good material, particularly
with regard to bending with a downside of a tendency to dull tools and
variability in quality dependant on the precise species and
environment. It made the Cedar out to be a rather brittle material,
although easy to work, although no precise mechanical properties are
available in my edition (1957 reprinted '60).

Appearance is a secondary consideration to strength in this
application and ease of working. Which would you consider to be the
better timber to use for a 9foot stem dinghy expected to last a while,
given that this is my first foray into traditional construction?

I would also be grateful if suggestions could be made about suitable
centreline materials, again, strength and suitability being primary to
appearance. Leather suggests a mixture of Mahogany (Utile is
available), Iroko or Oak in his book "Clinker Boatbuilding" but I'd be
interested in other's opinions.

Thanks for your time and suggestions.

Al

On Sat, 20 Sep 2003 05:19:16 GMT, "Brian D"
wrote:

Nobody mentioned it, so I will. If you are using epoxy, be aware that white
oak can sometimes work, sometimes not. I've heard a lot of arguments as to
why, but I've not seen a lot of answers for how to guarantee that epoxy will
stick to white oak as well as it sticks to other types of woods. White oak
is more rot resistant than red, so don't be tempted to use red oak because
it glues better.

That's right.

'Course, with any luck, one needn't use epoxy at all in this kind of
construction.

Nobody mentioned it, so I will. If you are using epoxy, be aware that white
oak can sometimes work, sometimes not. I've heard a lot of arguments as to
why, but I've not seen a lot of answers for how to guarantee that epoxy will
stick to white oak as well as it sticks to other types of woods. White oak
is more rot resistant than red, so don't be tempted to use red oak because
it glues better.

I'm using clinker construction in a bid to keep glue/resin usage to a
minimum. I don't particularly enjoy working with epoxies, but I do
enjoy working with mechanical fastenings and good quality wood. I may
have to laminate knees however as I can't come up with any sources for
grown crooks, and the stem will have to be, at least in part, a
lamination.

As far as the cedar goes, I only have Western Red available to me, I
apologise for not specifying this earlier, does this alter your
analysis? As a matter of interest, why are you recommending the cedar
over the oak, is it just ease of working?

Thanks

Al

Brian D wrote:

Nobody mentioned it, so I will. If you are using epoxy, be aware that white
oak can sometimes work, sometimes not. I've heard a lot of arguments as to
why, but I've not seen a lot of answers for how to guarantee that epoxy will
stick to white oak as well as it sticks to other types of woods.

I suspect that the problem lies in the tannic acid in the wood. I've been
working with green red oak lately, which discolors tool beds and cutting tools,
and the wood ends up with black streaks where you cut it with steel tools or run
it across an iron tool bed. Anyway, the point is that epoxy is neutralized by
acids, which is why vinegar is used to clean up uncured epoxy spills. It
neutralizes the epoxy so it will not cure, making it easier to remove. I suspect
that the same thing is happening with the tannic acid in oak.

--
Regards

Brian

On 20 Sep 2003 04:30:27 -0700, (Al) wrote:

Nobody mentioned it, so I will. If you are using epoxy, be aware that white
oak can sometimes work, sometimes not. I've heard a lot of arguments as to
why, but I've not seen a lot of answers for how to guarantee that epoxy will
stick to white oak as well as it sticks to other types of woods. White oak
is more rot resistant than red, so don't be tempted to use red oak because
it glues better.

I'm using clinker construction in a bid to keep glue/resin usage to a
minimum. I don't particularly enjoy working with epoxies, but I do
enjoy working with mechanical fastenings and good quality wood.
Great! I agree. Slathering goo is not particularly enjoyable to me.

I may
have to laminate knees however as I can't come up with any sources for
grown crooks, and the stem will have to be, at least in part, a
lamination.
There are specialist that offer crooks. Do a Google search. Here are
some suggestions for your side of the Atlantic:
http://www.covboat.demon.co.uk/sustainability.htm

If you have time you can easily get apple from an orchard which is
being pulled out. Takes time to season though.

As far as the cedar goes, I only have Western Red available to me, I
apologise for not specifying this earlier, does this alter your
analysis? As a matter of interest, why are you recommending the cedar
over the oak, is it just ease of working?

In the US, as far as I know, oak was never used for small boat
planking.

Oak is heavy and hard to work. It is stronger of course. The strength
is just not needed. The Lawley yard had a saying about their thin
scantlings on their dinghies. Something to the effect that if the boat
is going on the rocks, the difference between 3/8 and 7/16 is not
important.

Al ) writes:

...It made the Cedar out to be a rather brittle material,
although easy to work, although no precise mechanical properties are
available in my edition (1957 reprinted '60).

Appearance is a secondary consideration to strength in this
application and ease of working.

eastern white cedar is actually durable and easy to work. that's why
natives used it for the ribs and lining of birchbark canoes over all the
other native woods avaiable to them. clear, staight grained cedar was
split into 1/8 thick lining planks by hand. I owned a 22 year old cedar
skiff from www.cedarboats.com as a boy. Whenever my grandfather wanted to
whittle anything he'd pick out a piece of cedar from the wood pile.
Easiest wood to split to kindle a fire. I assume western red cedar would
have similar qualities. I use the red cedar in the framing on my small
cheap plywood boats along with lumberyard spruce.

--
------------------------------------------------------------------------------
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Hi

"P.C. Ford" skrev i en meddelelse
...
On 20 Sep 2003 04:30:27 -0700, (Al) wrote:

Snip

As far as the cedar goes, I only have Western Red available to me, I
apologise for not specifying this earlier, does this alter your
analysis? As a matter of interest, why are you recommending the cedar
over the oak, is it just ease of working?

In the US, as far as I know, oak was never used for small boat
planking.

Oak is heavy and hard to work. It is stronger of course. The strength
is just not needed. The Lawley yard had a saying about their thin
scantlings on their dinghies. Something to the effect that if the boat
is going on the rocks, the difference between 3/8 and 7/16 is not
important.

Now Oak work different in thin planks. Oak and Ash have some simularity with
these matters, but a thin Oak plank is a different thing than a softwood or near
softwood .
Oak don't like it to dry and ofcaurse you can prefere a good Larch from a bad
Oak, but done right , and with top quality wood Oak add more than just the good
looks, it will drain your bank account, unless you master just a few skills,
Oak is perfect for Lapstrake boats, and with Epoxy , you can lenghten any plank
so you can experience a lapstrake boat without butts, in Oak , where the rule
is, that this can be 2/3 thickness now it is stronger wood.
Still why do you bother, Computer drawings with unfolded planks do exist with
Cyber-Boat, but from my best knowleage , most unfolding is done from smothened
single curved skins . You can hardly find modern designs, that is projected and
the most "modern" lapstrake design, that you would reconise, is the danish
folkboat .
Still with materials you have a wide choice even the computer thing is fiddeling
and square box in inches , ---------- Nice boats was once build in this smart
building method, even it still is difficult to project in 3D ,you can chose high
quality , but please read about Oak before you decide, as what you need is the
true gray Oak not the "Oak" that is often used with furniture , do it carry
acid and is bone hard or is it a weak specie for outdoor use even nice and
without knots ; with Oak you can ask cirain qualities.
BTW. --------- A Lapstrake is the one that carry less frames , acturly they are
build without, and the ribs put in after, this acturly define the Lapstrake
method , compared other methods.
With Cyber-Boat you will find true 3D Lapstrake computer models, being the basis
for the unfolded planks , but I guess no one even care that with 3D-H you can
complete the Lapstrake method, with a perfect 3D-Honeycomb framework, at last
one reliable, that can be cut from sheet material, Anyway the 3D-H building
method, that offer you to build a new WTC without the weak trusses and hangers,
proberly will produce very few true Lapstrake boats. Mahogony is what I prefered
when I made boats .Only later I taken lame cheap chipwood into consideration,
and acturly offer plans for a tremendures Longboat , that you can build
extremely cheap , the plans are free ,the plans don't care if it is plywood or
crome plated Gold , but if you realy want to make good use of thin Oak planks,
why didn't you check the full-scale plans here ;

http://w1.1396.telia.com/~u139600113/

Or ;
http://groups.yahoo.com/group/Cyber-Boat/

O.T. you can se what 3D-H can produce , beside boat frames ;
http://www.designcommunity.com/scrapbook/2806.html

P.C.
http://groups.yahoo.com/group/structure-testbench/
Check Foto's folder for design.