Tuesday, 12 October 2010

Equinox, gale force wind, freezing hail! Spring's here.

Julie and I have moved from Waima.

We swapped our home of five years with people whose roots are in Waima. Their house in the little township of Rawene suited our needs and was similar in value. Now we live within one minute's walking distance to my work at Hokianga Hospital. No more car commuting!

Our new house looks out over the inner Hokianga Harbour so I'm back in touch with the pulse of the tide.

We moved in a convoy of small vehicles the 16 KM (12 miles) in the pouring rain one day in June
with lots of help from our friends.

I hooked up Toroa to the car on his road trailer and said goodbye to the place whare he was rebuilt.

I was alone in the car as we drove the Waima hill and descended into the Omanaia valley. All was going well until we came to the Rawene intersection from State Highway 12. at the turn, the right hand trailer tire burst.

I decided to proceed slowly on the rim, not having a spare to fit. A scene from that great Roger Donaldson film "The World's Fastest Indian" came to mind

The ride was a further 6 KM at 5 KM per hour, I was The World's Slowest Pakeha!

Flump, flump, flump, flump, wobble, wobble, wobble, It was slow noisy progress and to top it all off the car began to overheat. The cooling fans decided to go out in protest. Rovers are very self conscious cars and don't like drawing attention to themselves.

As we rolled past my place of work all my colleagues came to the roadside to jeer at me attracted as they were by my appalling progress. We finally pulled in to our driveway where I disconnected the trailer and left Toroa exactly where he stood.... until yesterday.

Over the three month gap Julie and I have established ourselves in our new environment. Last weekend I finished setting up my workshop with my wood tools on one side and my engineering tools on the other.
My saw bench is in its rightful place outside the workshop with enough undercover space around it to do some real work again.

With my now accessible tools I've unbolted the offending wheel and cut off the mangled tire from the rim. I took the wheel to our nearby garage where I asked the mechanic to fit a recycled tire which I found in the fill behind a retaining wall where my saw bench is now located. So I still don't know what's good and what's bad. Now I'm able to mobilise myself for another assault on the summer sailing opportunities.

My health is still not so good with my right wrist and ankle so swollen that I believe they will never be useful again. Just as well that I have a left hand and a left ankle that are still reasonably OK. (OK?
I think that "OK" must be derived from the Scottish "Och Aye") it has to be.

Toroa still needs a good water blast and also a coat of gloss paint. Who knows when that will happen?

Money's tight everywhere. Where did it all go? Rescuing the US economy?

Meanwhile I'm going to convert our little red Coleman canoe to every form of propulsion known to small boats. A yawl rig, row locks and outboard bracket, that way when I'm sick I can still go boating with minimal stress physically.

Saturday, 2 October 2010

Han's Comment on my blog post "Takapu the Proa a Dissertation"

Hi Han

I read about the Gondola in a "Wooden Boat Magazine" article many years ago. Since then I have wanted to study one closely, in action, to see what other benefits there may be from the asymmetry.

From my experience with the Proa I have learned that good design (especially design features with a long successful history) usually solves at least three problems at once.

I believe that this hull shape could simply offset the thrust of the oar but I believe that the answer may not be so simple, it may also have a more fundamental reason. One reason will almost certainly be the need for extra buoyancy over the side that the oarsman stands, on this long slender hull, to keep the boat level for the comfort of passengers.

Another will be the need to counteract a tendency that long slender hulls have to broaching. My experience with long symmetrical canoe hulls is that they have a strong tendency to track off course when a small force acts across the line of least resistance, i.e. wind or wave action. I believe the reason for this broaching action is the result of a pressure differential that gets started when the hull turns through the flow and water speeds up around the outside of the turning circle. This in turn generates lift which exacerbates the turning moment into a logarithmic spiral. The result is almost impossible to correct with any kind of lateral counter force like a long sweep or paddle (a disastrous situation in the congested busy waterways of Venice!).

With an asymmetric hull the pressure differential is constant and therefore more predictable for the oarsman to counteract. Lastly I believe that the oarsman exerts a slight diagonal force in the thrust sweep of his oar which results in lift from the rounded side of the hull. This thrust/lift combination in turn reduces the amount of effort required to move the hull through the water, the same phenomenon that a fish utilises when swimming.

Re rudderless steering.

The Patin Catala of Spain is a great example which has evolved into a very successful sailing class.  http://woodenboat.com/boat/?p=1358



Toroa by Harmen Hielkema & Mike Toy.

Header Photo: Toroa at Rawene by Julie Holton.

This blog is dedicated to the memory of my father Roelof Hielkema who instilled in me the willingness to learn.
These pages are intended to inform and add to the growing body of knowledge concerning the Canoe Culture of the Pacific, past, present & future, from the Tupuna, the Ancestors of the Pacific cultures to the people of the world.

These pages contain Images and text relating to our two proas, Toroa & Takapu, some history relating to our experiments & experiences.

The dissertation that I posted on this blog in April 2008 "Takapu The Proa" was written by me in 1997 in response to an assignment that I was set whilst studying for my design degree. The dissertation covers many issues that a proa enthusiast may benefit from reading about.

Waka define culture as culture defines waka

Waka reflect the individuality and uniqueness of a society which in turn is governed by the geography, geology, topography, climate, location, resources, isolation, origin, flora, fauna, flotsam, jetsam, etc.

Waka are our link to the past, they have shaped our present and define our future.

Waka are the vessels of knowledge, physical and mental development, freedom of bondage to the land, key to our inquisitiveness, expressions of our ingenuity and courage, our love of shape and form, the seat of our power.

Waka are the source of our material culture, from which all processes are derived.

Waka are who and what we are.