Old Kayak Bent Ribs Buckliballs

 

In my previous post, I described how one of my kayaks spontaneously changed shape in response to a shrinking skin.  While this type of response would generally have been regarded as mechanical failure, researchers are now trying to steer this kind of phenomenon to make it perform useful tasks, that is by creating a variable shape that can adapt to conditions.

Buckliball changing from large to small (left to right) in response to external stress

Paraphrasing here - One stress makes you larger, one stress makes you small, and the stress that mother gives you dont do anything at all. Never mind.  Pause for groans to subside.

geodesic dome assembly

By the way, if you didnt grow up in the sixties, which is likely, you probably missed Buckminster Fuller and his geodesic domes and also buckyballs which he invented and which I suppose buckliballs is a pun on.

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Unangan Aleut Kayak Terminology

Unangan kayak terminology has been set down in an article written by Knut Bergsland, Norwegian linguist, now dead, in Contributions to Kayak Studies, Eugene Arima, editor. I think thats the most commas Ive ever put in a sentence.
Ive been wanting to do an illustrated version of that article for some time, but what has discouraged me is the messy nature of the information in Bergslands article.  The information is messy because there was never just one official way of naming kayak parts in the Aleutians.  For one thing, Unangam Tunuu, the Aleut language had multiple dialects, at one time, probably as many dialects as there were tribal groups, something like nine, possibly more.  Along came the Russians, consolidated settlements and moved people around and a number of dialects disappeared.  The documented dialects remaining were the Eastern Aleut, the Atkan and the Attuan dialects. Then during WWII, the Japanese invaded Attu and moved the Aleut community there to Japan while the US moved the remaining Aleut population to the Alaskan mainland.  After WWII, Aleuts were repatriated, Attuans moved to Atka and so the only two dialects that were still alive were the Atkan and the Eastern Aleut. 
So when Bergsland collected his list of kayak terminology, he had some historical sources available that documented Attuan terms and speakers of both the Atkan and Eastern Aleut dialects. Not surprisingly, documented Attuan terms are fewer in number than for the other two remaining dialects at the time that Bergsland did his compilation. 
And terminology varied over time so that some kayak part may have been called one thing in the 19th century and then something else in the 20th.  Keeping all of this straight is not an easy thing. 
On top of that, we have to deal with Bergslands dense and sometimes cryptic writing style.  I give one example here.
"On top of the taamx^aax^, on the right side in front of the hatch, there was a hook for holding the paddle when not used, made of wood or baleen, or sometimes ivory (Atka 1952), possibly in the shape of a sea otter (Jochelson 1952:131), called in western EA (1909, 1950) x^aach(a)g^iilux^, in AA (1840, 1952) haachachag^iilux^, derived with the suffixes -g^i- + -alug^- place for having - from the above-mentioned term for paddle, EA (1778-) x^aasi-x, AA Au hassi-x."  inhale.  and so on he goes.  So you rub your eyes, go back to the start of the paragraph, try to match up the English with the Aleut term the two of which are invariably separated by a string of parenthetical phrases and hope you dont miss the period that lets you know that you have finally arrived at the end of the sentence.  By the way, the AA, Au and EA sprinkeled liberally around the sentence are abbreviations for the dialects respectively, Atkan Aleut, Attuan Aleut and Eastern Aleut. 
You get the idea.  I thought it might be nice to have a version of this that puts the Aleut term right with a picture of what it is referring to. 
I might put the pictures and words in this blog if I can make that work, the problem being that the blog software controls the size of the pictures, (small) and the layout of the text. Stay tuned.

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Bent Shaft Paddles

Ive been making a number of prototype paddles at the request of a friend and promoter of my paddles.  After a number of weeks I came up with two winners.  One is a bent shaft Greenland style paddle.  The other is an Aleut style paddle with some amount of extra bend added to it.
There were some other paddles in the mix that werent winners but they were instrumental in helping me figure out the specifics of what made the winning models work. I have made Greenland style bent shaft paddles before and quite by luck come up with the right design, but this time, I did some deviation from the winning model only to find that the original was still the best. The Greenland style bent shaft may actually have originated in East Greenland as reported by John Brand who found some examples of these paddles in museums and originally thought that they were just straight paddles that had warped over time, but after some reflection decided that they were actually made that way on purpose.
The bent shaft Aleut paddle is not completely new.  I had made two of these before for a friend but never actually paddled them myself.  This time around I did use the bent shaft Aleut paddle and found it to be a useful variation on the standard version that I usually make.

Four paddles out for a test run. From left to right, a Greenland breakdown for a customer, an Aleut with some bend in the direction of the ridged face, a Greenland style with significant bend and another Greenland style with moderate bend.

One of the key aspects of a Greenland paddle is that it is highly symmetrical, that is, no matter how you hold it, its performance is the same.  The Aleut paddle by contrast has a lower degree of symmetry. You can switch right and left blades without changing performance but you cannot change ridged face for flat face without changing performance.  The reason is that in one configuration, the face of the paddle trails the axis of the loom while in the other, it leads the axis of the loom.  Although the amount of offset is small, it nevertheless makes a difference in the way you need to move the paddle through the water to get it to work.
The same is true of the bent shaft Greenland paddle.  The slight amount of offset of the blade has it either leading or trailing the axis of the loom depending on how you hold it.
My insight while doing the testing on the bent shaft paddles was that when you pull a paddle through the water, you move it through an arc during which the angle the blade makes with the water changes.  The efficiency of the paddle is at its greatest when the blade is perpendicular to the surface of the water. As the stroke progresses, the angle the blade makes with the water changes from the vertical and the amount of force you exert that translates into forward motion decreases.  At the same time, the boat is accelerating forward and the water is accelerating backward so that as the stroke progresses it becomes less efficient.  So having the shaft bent to make the blade more vertical at entry into the water improves its efficiency.
On the other hand, when the paddle is used in a low angle cruising position, that is, with the loom held low and close to the deck then the paddle held so that the blade trails the loom makes the blade self orienting and requires less of a tight grip to keep it properly oriented.  While this stroke generates less thrust than the high angle stroke, it is more efficient at lower cruising speed and less tiring in headwind conditions or against the current conditions.
Whether my understanding of the mechanics of these paddles is correct or not, the fact is that they work in practice as confirmed by speed trials with a GPS.

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The Americas Cup

The Americas cup is one of those sailboat races that has been going on for a long time and happens again and again at various intervals.  Seeing as it involves large sailboats, only the very rich can compete, albeit with hired crews.  This year the race or part of the race is happening in San Francisco Bay on which I live and so the news about it reaches me.  I have nothing to offer on the merits of the race but it did happen that the Swedish race team is working out of an aircraft hangar close to my own modest boat shop and so on the way to work or going home from it, I see the boats that compete in the event.  So I want to offer some photos of the Swedish boats because I find the boats interesting.
By the way, I understand that the current crop of boats are a short version of what will be in the final competition.  And all the boats were built in New Zealand by the same builder to the same specs so that he race is about who has the best crew and not about who has the best boat.

 This is one of the two Swedish boats tied off to a buoy in the Seaplane Lagoon.  In the background, one of the maintenance hangars from the Naval Air Station days.

 The boats and the sails are moved in and out of the water by a crane.  They are not that heavy as boats go, around 3000 pounds. 

 Here is the boat itself, without its rig.  Dagger boards are in their retracted position.

 And the Americas Cup logo and Swedish flag.

 The boat has a wing and a jib.  The wing is symmetrical about the center plane unlike an airplane wing which is usually flatter on its bottom face.  

 And there are the Swedes, out on the bay doing their stuff with their support boats motoring behind them.

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Old Kayak Bent Ribs

Ive got one more set of photos on deck for the old kayak series.  Not that I dont have more old kayaks or old kayak photos, but its a matter of being able to find them.

Todays tale of woe is all about the lethal combination of heavy nylon fabric and a boat left out in the sun for too long.  Nylon, if you dont already know, contracts with high temps and as you can see in the photos, pushes down on the keelson and bends the ribs into a reverse curve.  This isnt that bad, mostly it makes the hull a little flatter.  What is worse is the end to end shrinkage of the fabric which compresses the keelson which responds by taking on something of an S curve when viewed from above.  This makes the boat pull to one side.  But even that is not lethal and I managed to fix it with a rudder.  Its just that the boat is not the elegant craft that you started out with. So beware of heavy nylon combined with heavy sun.

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