| |
Top
Easy
Construction
You may wonder, can
I even build a kayak like this? If you like a little challenge, you
certainly can! There are thousands of wood strip kayaks around the
world, many made by people for whom this was their first building project
of any kind. The vast majority of builders are the 'weekend warrior' types
who relax by this artistic endeavor.
It is almost hard to believe but many paddlers who build wooden kayaks
will also go to any length to find a place to do it.
Wood strip kayaks are being built right now by amateur builders in garages,
sheds, lofts, basements, hallways, attics and of course in livingrooms
and bedrooms! Few people even asked me how to build their kayak in TWO
sections so that it would fit in their space. It seems like the ingenuity
and persistence of the wood strip builder just knows no limits. Looking
at the fruits of their labor, it is easy to understand why; The muse of
creativity will not be silenced.
The simplicity of kayak building starts with the full
size plans. You will immediately appreciate the speed with which
you can put together the whole set of stations (forms). Furthermore, with
the exception of spacing the stations on a "spine"(strongback),
you need not MEASURE anything! The
entire mold is designed for visual alignment using only a level. One
sheet of plywood and particleboard is all it takes to make a precise
form.
Using strips to build the body of the kayak is the best feature by far.
So what if you break a strip... pull out a few staples and you are in
the game again. Made a big gap? When it gets filled, glassed, and varnished
you will have to search to find it. Stripping will simply tolerate errors
that would be unacceptable in most other building methods.
Stapling pliable strips of cedar over the gentle curves of the forms,
sanding foot by foot or cutting hatches a bit at a time gives you great
control over the quality and pace of the project. You can build as
fast or slow as you want.
Fiberglassing IS easy, too. Poor quality of resins from years past has
generated too many horror stories that make novice builders unnecessarily
apprehensive. These stories could be generally summarized as: "Wrong
resin and wrong instructions for the wrong job under wrong conditions".
The epoxies used for clearcoating wood are of the best quality and should
not be confused with the smelly "esters" or the 5min epoxy tube
in a hardware store. With the slow hardeners, you will have the hull almost
completely coated before you need to squeegee, and it will take a few
more hours before everything sets.
Over the years I have worked with many resins but the ones I use now,
both the MAS and West
System epoxies have excellent properties that makes them
quite foolproof. If you want to find out more about epoxies check out
the Epoxy Test page to see how six popular
epoxy types compare in UV degradation and other qualities.
Top
Lightweight Shell
Light weight is the forte
of all core structures used in boatbuilding and wood strip kayaks are no
exception. They belong to a class called Monocoque Shells. (From French-
Mono: single and Coque: shell)
Monocoque shells are structures where the walls support themselves including
all other loads and stresses. They don't need any internal reinforcement
such as ribs, stiffeners etc. This eliminates a lot of superfluous weight.
Even smaller craft such as single skin fiberglass kayaks are monocoque but
as their size increases such as in expedition or double kayaks, the skin
needs to be built thicker to maintain sufficient stiffness. The price of
that is exponentially increasing weight.
This is where wood strip sea kayaks really shine! The composite core has
sufficient reserve stiffness and strength that even much longer and larger
Expedition kayaks can stay light.
All this means is that everything you do with the kayak is simplified.
Loading and unloading kayaks, for example, can be quite a chore but my even
my wife can put a strip kayak on a car roof with ease. Low weight also means
easier paddling, maneuvering and covering larger distance with less effort.
Take an 18ft single skin fiberglass kayak (heavyweight), for example. It
will weigh about 60 to 64lb and its kevlar counterpart can shave this by
about 6lb. Compare this to a solid red cedar kayak of the same size.
Its weight will span from 39 to 50lb max. depending mostly on the fiberglass
lay-up.
It gets better still; A 21ft fiberglass double will be around 85
to 95lb but the same double "stripper" such as the Cape
Ann II will be no more than 75lb! This includes hardware, rudder
and everything else attached. So, while the commercial builders struggle
to shave 2-3lb with the latest vacuum bagging techniques, with a 'stripper',
you get an immediate 10-15lb weight saving bonus!
Let me say a word of caution about exotic wood. If you want the lightest
possible kayak, limit your inlays and decorations to Cedar and low density
wood. Careful use of hardwood is fine but don't be surprised that one 18ft
strip of beautiful Bubinga may weigh as much as 1lb (ugh!).
The most suitable wood in terms of weight and workability:
Top
Strength
& Stiffness
The mechanical properties
of the sandwich core are the main source
of strength but there is an additional bonus that comes with wood strip
kayaks.
The cedar strips forming the kayak are inherently stiff and strong themselves,
making the shell far stronger than if it was built using a different
core. Of course, all other variables remaining the same (thickness, lay-up
etc.). No other lightweight core material I know of (besides plywood) has
the same self supporting qualities. You will notice this unmistakably, as
soon as the kayak mold is completely stripped. The 1/4" shell stays
rigid even in the spans between the stations of the form. There is no flex
when you sand or plane.
One enormous advantage of a rounded wood strip kayak is its 'compound'
shape. Ever tried to 'flex' an egg shell of an unbroken egg? It is enormously
stiff because of its compound shape, not the thickness of the shell.
Once you break the egg, the shell is as fragile as glass. This lesson of
natural design was quickly learned by medieval architects who realized that
the only way to build large cathedrals was with 'compound' domes not flat
roofs. The examples of this principle are everywhere around us and the same
applies exactly to the smooth round surfaces of wood strip kayaks.
A flat plate such as a plywood panel will always be less stiff than a compound
shell made of the SAME material and thickness.
Because of this structural advantage, you will be very surprised how solid
the whole kayak feels when it plunges into deep wave troughs - a massive
slam without a shudder in the hull. When you are out there, far away from
the shore and you get in a really 'hot water' you will thank yourself that
you are riding a solid wood core kayak.
|
Easy
Construction - Can I build a wood strip kayak like this?
