Paddle Dynamics

Three Greenland style paddles on display at the boat ramp where I just got done testing them. The breakdown paddle on the left had the tips thinned. The one in the middle had the varnish touched up. Note that the paddle in the middle has a more curved face than the one on the left which has a flatter, thinner face. The one on the right, the long one, is one I just finished carving.

I recently did some maintenance on two paddles for a client of mine.  One of the paddles was just worn and needed a little sanding and a coat or three of fresh varnish.  The other one was making noises in use because the tips were too blunt so I made the tips sharper.  Before returning the paddles, I took them out to test because that is the right thing to do when you make a repair and charge someone for it.
Oh yes, there was also a third paddle, one that was supposed to be a blank for a paddle making class that a prospective students wife had given him as a Christmas present.  Three years or more passed and the student still hadnt managed to arrange a class date to finish the paddle, so I finished it just get the thing out of my shop.  And so while I was testing the other two paddles, I thought I would test this one as well.
Things got off to a slow start.  The boat I used for a test vehicle belonged to someone else and had very slack deck lines that made it hard to keep spare paddles on deck but after some experimentation, I managed to figure out a way to carry the spare paddles while testing.
Paddle testing for me is usually comparative.  Given my testing tools which consist of myself as motor and test evaluator, a gps as speed indicator, a kayak and some suitable body of water to float the boat and offer resistance to forward progress, the tests tend to be subjective and relative.  That is, I dont have absolute numbers at the end of the test.  I take several paddles, paddle back and forth and compare the performance of the paddles under more or less identical conditions.  The two things I can measure are speed and the amount of effort I put into paddling.  Effort is hard to measure so it usually means that I try to make the boat go as fast as I can with a given paddle.  And when I am going as fast as I can, I measure the speed with the GPS.
Usually what happens is that one paddle feels better than another or one paddle gives me a higher top speed than another.  And in general, results tend to be vague impressions more than anything rigidly scientific.  But some good can come out of even an unscientific test, as happened in this case.
Let me share my observations.
As expected with the three paddles pictured above, the long paddle gave me the best top speed. This paddle was 98 inches long.  The two shorter paddles were both 84 inches long.  Normally I like a paddle that is somewhere between 88 and 92 inches long so I expected the 84 inch paddles to be slightly underpowered.  As it turned out, they produced top speeds not that much slower than the long paddle.  Acceleration with the short paddles was lower than with the long paddle, but by and large, once I got the boat going, the short paddles did pretty well.
What was happening was that the hull speed of the boat was the limiting factor in the test and not the paddles.  That is,  the short paddles were adequate for getting the boat up to hull speed but couldnt push the boat much beyond that.  And thats probably adequate for most situations.  The long paddle with its greater blade surface could push the boat beyond its hull speed but at the expense of greater effort.
So the problem with testing paddles using a GPS and a slow boat is that just about any paddle can push the boat up to hull speed and further effort even with a larger paddle produces little extra speed so that measurement of top speed are more an indication of the boats limitations than any measure of the paddles effectiveness.
It would be nice to have a meter that could measure the speed of the boat, the resistance offered by the boat and the power needed by the paddler to keep the boat at that speed.  If such a thing were available, it would be able to offer a good comparative test of different paddles effectiveness.  Even if two paddles were able to bring a given boat up to the same speed, the one that requires less effort by the paddler would be the better paddle.  However, since there is no good way to measure that effort, it is hard to make meaningful claims about the effectiveness of one paddle vs. another and the question of which of two paddles is the better one remains largely subjective.

Read More..

The Giant Sequoia and Some Random Thoughts on Trees and Wood

It is one thing to see wood at a lumber yard and it is quite another thing to see it in the form of a living tree.  Unlike the stuff in the lumber yard which gives little evidence of where it came from, the living tree obviously speaks for itself.  It is not a product but an individual being with a considerable amount of character that makes it distinct from others of its kind, especially when old.
The musings I am about to deliver on the nature of wood were prompted by a trip to Kings Canyon and Sequoia National Parks.  The two parks are adjacent to each other, with Sequoia to the south and Kings Canyon to the north.  The only way to approach these parks by car is from the Central Valley of California.  Kings Canyon is adjacent to the city of Fresno and Sequoia is adjacent to the city of Visalia. Giant Sequoias can be found in both parks, although Sequoia National Park has more of them. Coming from the Central Valley which is flat and almost devoid of trees except for fruit trees in the orchards, it is hard to imagine that one is about to enter a mountainous zone where the huge sequoias live. 
But on to some pictures. I would like to say off the start that it is impossible to convey the massiveness of these giant trees in photographs.  The best one can do is show part of the tree with a human or two next to it for scale.  But even then, the photograph cannot capture the sense of presence that these large trees convey. Nevertheless, here are some photographs.

This trunk of a Sequoia has been hollowed out by fire and decay and so it is possible to walk through and along the trunk. 

 

Here is another sequoia that has fallen.  Someone cut a hole through it that one can walk through. The hole by the way is about seven feet tall.

Here is a picture of the tree named the General Sherman.  This is the worlds most massive living being.  It is suspected that some of the trees cut down when logging first began were larger than this, but General Sherman is currently the largest individual.  Its diameter at the base is in excess of 30 feet. 

 

 And here is the root ball of a recumbent sequoia, 30 feet from side to side.

 And using a deer for scale.

 And more humans for scale.

 And a tree hugging human for scale.

Even the branches of these trees are huge.  This one fell off a tree and the park service left it laying where it fell to give people an idea of their large size.  The largest branches on the General Sherman are about 7 feet in diameter.

 

The sequoias are not the tallest trees in the world.  That distinction goes to the coastal redwoods.  Neither are they the oldest trees. That distinction goes to the bristlecone pines of the White Mountains, one valley to the east of the Sierra Nevada.  But the sequoias are the most massive trees. Their trunks seem to be columns of almost constant diameter rising some 300 feet into the air and then seeming to end abruptly in the older specimens.  

Someone took a slice of a sequoia trunk and propped it up at an angle for the edification of the public. This slice represents roughly 2000 years of growth.  Age is determined by counting the annual growth rings.  The age of standing trees has to be estimated because there apparently is not any equipment that can remove sample cores of the requisite length, roughly 18 feet needed to count all the rings from the center of the tree to its edge.

 This is a side view of that specimen.

 

And here is a closeup of the growth rings in that slice.  The top of the picture is closer to the center of the tree where the older wood resides.  The crack running horizontally through the picture is a fire scar.  Moving downward toward the crack, the growth rings get ever closer together, an indication of ever diminishing growth.  After the fire, there is an explosion of new growth that again diminishes over time.  Apparently, fires burn the vegetable matter on the ground and release nutrients into the soil which spur new growth for a few decades until most of the nutrients are once again tied up in vegetable matter until the next fire comes along.  Also, note the little circular impressions just above the crack.  These are probably cores taken for carbon 14 dating and then plugged. 
When botanists try to estimate the age of trees based on diameter, they look at slices like this one and try to get an average count of growth rings per inch since as this picture shows, ring density changes with every fire and also with annual precipitation.

There was no sign indicating what sort of wood these park benches were made out of, but I suspect that they were made of sequoia wood. Yes, they haven;t stopped logging sequoias.  Not all of them are protected. Some of them are on private property and some of them are in national forests which are administered by the US Department of Agriculture which regards forests as cropland meant to be harvested. Not an editorial comment by the way. If we want to make stuff out of wood, we have to cut down trees.  More on that at the end.

Here the park service has done a prescribed burn or someone dropped a cigarette. In any case, not much damage was done.  For a long time, the park service used to suppress fires but found that periodic fires are better than monster fires fueled by debris on the ground that has accumulated for too long.  Also, they found that sequoias will not reseed very well without fire.  Fire turns vegetable matter into ash, releasing nutrients for the seedlings to grow.  Fire also kills off young trees that would otherwise shade out the new seedlings. And fire also opens up the cones to release seeds.  So now the park service does prescribed burns which do little damage but reduce the amount of fuel that could produce more dangerous fires.

This picture shows young sequoias coming up with the older fire scarred sequoias in the background.  The ash and the light also allow ferns to grow.

Another view of the burned ground.  Yes the ground burns since the top six inches are a compacted mass of needles and small branches.

Almost every old tree shows fire scars. As a matter of fact, I have never seen so many burned trees as I saw in Kings Canyon National Park.  In the national forests, fire scarred trees are more rare since those are logged over on a more regular basis and fires tend to be suppressed because the trees are regarded as a crop, not a part of an ecosystem in which fire plays a beneficial role.

This is a side view of about eight inches of fibrous sequoia bark which lacks resin and therefore does not burn readily.  Bark on sequoias can be up to two feet thick and this is what lets them grow old in an environment where fires occur naturally every seventy years or so.

Here the fire burned into the trunk of the tree but the segment at the left is still alive.  Every yearn the bark spreads sideways to cover over scars and in time will cover them completely.

 

Here is a segment of  a branch. The heart wood is red and the sap wood is a lighter color.  The heart wood of the tree is dead.  The sapwood is the part of the tree that is still alive and growing and is where the tree adds more wood around the outside of the tree under the bark. For purposes of lumber we want heart wood because the sap wood decays more readily.
So I was curious what kind of wood sequoias are made out of or perhaps more properly, what kind of wood they grow.  Right on the ground near this broken branch above I found a small piece that had broken off when that branch came down.  It was red in color like that branch but on carving some off, I found that the red color was mostly a product of weathering and that the wood was a lighter color.  It was also surprisingly light, similar to redwood but with a consistency that felt more like cedar.  And then it occurred to me, why not?  If you are going to grow large, why not build yourself out of light wood.  Since most of the weight of the tree is in the trunk, the lighter it is, the larger you can build it.  Sequoias and other conifers dont have huge spreading branches like oaks and so most of their strength is needed to resist the compression of the mass that piles up on top of the roots, mostly in the trunk.  Hardwoods like oak on the other hand that put out large lateral spreading branches need stronger wood to resist bending forces and stronger wood is heavier.  And so boat builders like conifers because they produce long straight trunks that can be cut into long straight boards.

As a boat builder I use wood. And as a paddle maker I also use wood, especially wood from older trees since they are the ones that have the wood that is clear of knots. But to use wood without a knowledge of what happens to the forests where that wood is taken from is akin to buying a pork chop in a supermarket without knowing that one needs to kill pigs in order to make that pork chop.

The impact that the visit to the sequoias had on me was to see trees as individuals.  Young trees a few decades old, especially in large quantities tend to be rather similar in appearance and lack distinction as individuals.  Every tree seems to look like every other tree and so one can more readily regard them as a crop to be cut for use as lumber.  Old trees however, tend to be distinctive, each one different from the next and since in the case of the sequoias they may have been around for perhaps two thousand years or more, one is forced to realize that cutting one of those trees for human use deprives the rest of the world from the presence of such old trees for another two thousand years.  And so it seems that to cut such old trees is rather frivolous because the gain in lumber does not make up for the loss of the presence of the individual.  

And yet, as a wood worker, I use wood.  And since I make objects for other people, I want to give them a good product free of flaws and blemishes.  I want to give them something that looks like wood is something that is extruded by a machine. 
Perhaps I need to rethink my approach.  If I do not want to participate in the cutting of old trees, then perhaps I need to figure out a way to make paddles from younger trees whose wood is not quite as perfect and blemish free as that of older trees.  Stay tuned, I have some younger trees in mind that I will experiment with

Read More..

Paddle Design Stability

In this post I want to focus on ways to design a paddle so it orients itself in the proper direction for paddling without a lot of effort on the part of the paddler. A paddle that requires a tight grip to keep it in control will sap the energy of the paddler and cause fatigue and diminished efficiency.
Not surprisingly, there is more than one way to make paddle orientation easier to control. I will examine three different ways all of which can be used in various combinations. I should also mention that the intended use of the paddle, whether it is meant for racing, cruising, surfing or rolling will have an impact on how it should best be held.
Most traditional paddles have oval or egg shaped looms with the longer dimension of the oval perpendicular to the face of the paddle blade. The oval shape makes it easier to keep the loom from twisting in the hand than a loom with a circular cross section.
A second way to keep the loom from twisting in the hands of the paddler is to hold the paddle at least partly by the root of the blade where it joins the loom. For instance, in a shouldered Greenland paddle, the index finger and the thumb circle the loom while the other fingers and the rest of the palm circle the root of the paddle blade. The flat part of the blade resting against the flat of the palm gives the paddle stability and keeps it from rotating in the hands of the paddler.
I thought at one time that it was only the Greenland paddles that were held this way, but there are some photos of Unangan (Aleut paddlers) that also show them holding their paddles so that at least part of their hand is on the root of the blade and part on the loom.
A third way to stabilize a paddle is to design it so that the paddle blade naturally wants to orient itself in the right direction when the paddler pulls on the loom. This trick only works for paddles that are asymmetrical, that is paddles that have a front face that is different from the back face. When you pull this kind of paddle through the water at some random angle, it will have one face that will naturally orient itself in the direction of travel while the other face orients itself away from the direction of travel. It is like a wind vane which if put sideways into the wind will turn its head into the wind and its tail out of the wind. Examples of this kind of paddle are the Unangan (Aleut) paddle and bent shaft paddles in which the face of the blade slightly trails the loom as the paddle is being pulled through the water.

In these two closeups of Unangan paddlers from the same boat, both paddlers are holding the paddles with the flat face toward the back.  The interesting thing with these paddles is that the weather vane effect would favor holding the paddles flat face toward the front but the shape of the paddle in the areas where paddlers held it also make the opposite orientation stable. The photo was no doubt posed and both paddlers are just holding the boat in position rather than paddling forward.  They may actually be paddling backward. So it is hard to tell whether this is the way they held their paddles when moving along, but regardless of what was happening when the picture was taken, it seems that the shape of the loom allows the paddle to be held in a stable manner regardless of orientation.
This also brings us to the question why so many commercial paddles have looms with round cross sections while traditional paddles almost without exception have looms with oval cross sections.  I suspect the reason is that is simply so much easier and cheaper to manufacture looms with round cross sections.

Read More..

How Many Kayaks Are There

I lifted this photo off facebook.  It shows a bunch of kayaks and canoes all rafted up together to set a Guiness Book world record.  The photo came with the following info:
"The largest raft of canoes and kayaks consisted of 1,902 boats and was achieved at the event "One Square Mile of Hope". The event was sponsored by the Central Adirondack Paddlers Society, and took place on Fourth Lake in Inlet, New York, USA!"
The photo got me to thinking, how many kayaks are there in the world right now?  Probably lots and lots, maybe even millions, thanks to the miracle of injecting plastic into a mold.  This is not intended to be a slam on plastic kayaks by the way.  Even home built skin on frame kayaks in the world right now must come close to the number of skin kayaks that existed at the peak of population in the Arctic. 
Aleut population at its maximum was estimated to be about 20,000.  Perhaps a third of that population was adult males each of whom supposedly had a kayak. So at its peak, there were perhaps 7000 kayaks in the Aleutians. 

Read More..

Iqyax Baidarka Research

I am currently working on the improved Bay Boat, that is, San Francisco Bay Boat.  The baidarka I had been paddling most frequently is about 20 years old, re-ribbed once and reskinned a number of times and a fairly close replica of an Atka baidarka.  This particular boat just got a paint job.  The old paint job consisted of a varnish base covered some time later by a color coat.  The color coat was peeling badly, probably because I never sanded the base coat before putting on the color coat.  The re-paint is done now.

 

The baidarka is on the left with its new coat of gray latex house paint.  I store my boats outside so the most critical job of the paint is to keep the UV rays from degrading the nylon skin.  Opaque paint does a good job of that and more cheaply than exterior varnish.  Thats my King Islander to the right of the baidarka.

The only drawback of the old baidarka is its narrow width and fairly deep hull which makes it a challenge to keep upright.  Its actually not that bad once you get used to it, but its not a boat that you can just sit in and relax.  When youre not moving, you need to brace or have the paddle out as an outrigger.  

So, enter a wider version of the Atka iqyax^.  The idea behind this boat is sufficient width to allow lounging without constant bracing but not enough width to make it slow, a boat suited for longer stays on the water, like a bay crossing, about a one hour affair.

Inside view of the hull.  Good width and flat rib profile to make the boat stable. 

And an outside view of the hull with the stringers temporarily taped and lashed in place.  Also note the open jawed bow, a configuration I have been playing with, mostly because this configuration makes it easier to align the keelson with the bow assembly.

Also the upturned nose of the other bow configuration is more prone to breaking because the grain runs across the upturned part instead of in line with it. 

Read More..

Unangan Single Bladed Paddle to Double Conversion and Back Again

When I first saw this picture of a double bladed paddle, I thought it was a new Aleut type.  And so I made a copy of it.  As it turned out, it was too short for me and I never used it after its original trial. Later, the photo showed up on some forum and somebody perceptive pointed out that the double bladed paddle looked like it was two single bladed paddles lashed together, possibly after having been sawed to better fit together. Sure enough, if you look carefully, you can see the lashing that made one paddle out of two.  The picture was taken at the Chicago Field Museum when it was the site for the World Fair.
The problem with using a single bladed blade shape for a double-bladed paddle is that the single bladed paddle is designed to be used more or less vertically so that the full blade is immersed in the water at then end of the stroke.  The blade on the double bladed Aleut paddle is widest near the tip so you can get more blade in the water at the beginning of the stroke at a lower blade angle.

Click on the photo for a better view.  Note the single bladed paddle tucked under the improvised double bladed paddle.

Just recently, it occurred to me that the one paddle out of two process could be reversed and if I cut my too short double paddle in half and spliced some more wood to it. Then I could have two usable single bladed paddles instead of just one unusable double bladed paddle.

The double cut in half on a bandsaw. The half on the right already has its extension glued to it. 

And here, a close-up of the sliced portion of the paddle.

Soon as my paddle transformation is complete, I will report on the performance of these paddles.

Read More..

Unangan Aleut Paddle Orientation Revisited

I already have two posts on how Unangan paddlers held their paddles.  To read them, type paddle orientation into the blogger search box on the upper left side of your screen.
Most recently, I have been having conversations with Rob Macks of Laughing Loon Kayaks and he graciously gave me access to some pictures he took of Unangan paddles when he last visited the Smithsonian Institution. Unfortunately I cant post them without the permission of the Smithsonian so I will resort to photos I have posted before.
I havent seen any Unangan paddles in person, nor handled them.  Rob has. What he pointed out to me is that the Unangan paddles have looms that are roughly triangular with one of the corners of the triangle lining up with the ridge that runs down the center of one side of the paddle.  The looms are also quite deep, commonly about 1-3/4 inches.  The base of the looms triangle lines up with the flat side of the blades.  What Rob pointed out is that trying to hold the loom with the ridge of the blades facing backwards is uncomfortable because trying to paddle that way has the ridge digging into your palms.
To test the idea of the uncomfortable loom, I carved a loom section out of a piece of two by four with a dimension of 1-3/4 inch deep and 1-1/4 inch wide and roughly triangular with rounded edges so it became more egg-like than triangular in cross section. 
Well, the loom seems a little more comfortable held as shown in the photo below, but not all that uncomfortable the other way around either.  What might be more of an issue, and I have noticed this with one paddle that I made is that a loom with a 1-3/4 inch by 1-1/4 inch cross section is that a loom with these proportions limits how far you can rotate it in your hands to get the right blade angle for efficient paddling.
I will be making a paddle with a loom that is an accurate replica of the Smithsonian type paddles to test this hypothesis.  The idea is that the triangular loom shape will orient the paddle in a favorable way when held flat side back and an unfavorable way when held ridge side back.  

So here is a photo of an Unangan paddler with his paddle.  He looks like a real paddler and so I would expect that when posing for a picture, he would hold the paddle the way he would hold it for paddling, that is, flat side facing backward. Note that the paddler is holding his paddle where the loom transitions into the blade.

This appears to be where you would be holding that paddle while paddling. If you click on the picture above, you will see that that is where the front paddler is holding his paddle.
None of this is conclusive of course, but I suspect that a lot of the dispute about how Unangan paddlers held their paddles has to do with opinions based on Unangan style paddles that arent very close replicas of the originals.  How you hold a paddle has a lot to do with what is comfortable for you and that has a lot to do with how the paddle was carved and also with how the blades were carved.  Some fairly subtle variations in construction of both loom and blade can easily bias use of the paddle either ridge or flat side towards the back. And as I noticed with my own Unangan style paddles is that I can use them either flat or ridged side back and both ways work although flat side back typically generates more thrust.
Another thing I noticed while looking at Rob Macks photos of paddles is that on some of them the ridge on the blade was not sharp but rather about a half inch wide and flat.  This type of paddle looked like the basis for the one with the groove down the spine.
One of the paddles in the Smithsonian was also quite long, 8 6" according to Rob.  It falls into the category of extra long paddles that Jeffrey Dickrell, historian of Unangan kayaks has reported seeing in some historical photos.
So there you have it.  All in all, I suspect that Unangan paddles varied a bit from place to place and from paddler to paddler.  I also suspect that once Russians pressed Unangan paddlers into hunting sea otters for them, paddle and kayak styles became more homogenized than they were before the arrival of the Russians.

Read More..

Fire Good Fire Bad and Whatever Happened to Pyrodiversity

I recently bought a book called California Indians and Their Environment. California Indians unlike most of the other Indians in what is now the US had never developed any agricultural technologies.  Instead, California Indians made their living exclusively off plants growing wild in their environment.  However, Indians managed their environment by burning practices that encouraged their food and medicinal plants to thrive.
Enter the Europeans.
Fire, an environmental management tool for the Indians was a threat to property for the Europeans.  The use of fires intentionally set  by the Indians, what are now called prescribed fires was outlawed by the Europeans. I imagine that the dwellings of Indians were subject to fire damage just like the dwellings of the Europeans but given  that the Indians set fires to manage the vegetation in their territory did not build dwellings where they would get burned down.  In addition, Indian dwelling may have been more temporary or movable and therefore more disposable or more easily relocated if a prescribed burn was called for.

I have never seen the reasons for antipathy to fire spelled out anywhere in text, but the idea that fire is bad seems almost self evident probably at least in part because of a massive public relations campaign by the department of Agriculture.  The appeals were mostly emotional and aimed at a population that probably had very little contact with forests on a day to day basis. The reasons for preventing forest fires are primarily economical and have little to do with ecological concerns.  Fire is a natural phenomenon and ecosystems have adapted to fire and in many cases depend on fire to keep the ecosystem in balance.  Not so in National Forests managed by the Department of Agriculture.  National forests produce lumber.  The lumber is sold to lumber companies and the Department of Agriculture collects money when the trees are cut down.  Trees that go up in smoke dont produce any revenue and whether by training or by natural disposition, most people, myself included dont like the look of burned over forest. 
The National Park people on the other hand dont sell any lumber and so they can afford to let forest fires burn.  No revenues are lost as a consequence.  Perhaps park attendance goes down during a forest fire but quickly picks up again afterward.  National parks even do prescribed burns since some trees like the giant Sequoias dont reproduce unless the ground is burned over.
But back to the Department of Agriculture anti fire campaign.  While the motivation to prevent forest fires was primarily financial, the advertising campaign instead focused on the fact that forest fires could potentially kill cute baby deer and bears, and so Smokey the Bear was created.

OK, so fire wastes resources, not to mention displacing or possibly orphaning young deer.

Heres the orphaned deer theme again.  no mention of wasted resources this time.

And again, this time, who knows, might be Smokeys nephew thats getting bandaged up there.  Smokey wants to know WHY?

This time, no orphaned animals, but the implication is clearly that those two cubs would be in a heap of trouble if there were to be a fire.  Smokey meanwhile is taking a break from shoveling dirt on top of camp fires to read a fan letter.  In the background, city dwellers recreate on a lake in the woods at a forest service campground in an environment of statuesque ponderosas unmarred by fire.

And for the children, a reminder that theres lots of critters that would be indisposed by forest fires, the advertising campaign bleeding out into the culture at large via childrens books.

And finally, WWII poster.  Needs an update there with Putin and Osama.

Read More..

Double Ridged Unangan Aleut Kayak Paddle

A while back, Suzawa Ikunori of Japan posted some pictures of several Unangan paddles in a Japanese Museum. Unlike most of the Unangan paddles I had seen before which have one face which is more or less flat and one face which has a ridge running down the center,  these paddles had ridges running down both the front and back faces. 

The paddle is quite long assuming the the loom is the usual length of about 22 to 24 inches.

This photo shows three of these double ridged paddles.  The middle one seems to have some damage to the tip.

And this is a drawing of the paddle blade and the relative size of the ridges and the location of the blade edge.
It appears that the layout of the blades is similar to that of the single ridge paddles except that the normally slightly convex side of the blade also has a ridge carved into it.  I have taken one of my single ridged paddles which I found to be too stiff and heavy and have carved away at the flat face of it to create a low ridge on that face.  Testing of this configuration is still pending. 
One thing that double ridged paddles might eliminate is arguments about which is the right way to hold them, ridge forward or ridge backward.  But since the paddle is not symmetrical, there is still room for argument.  I hope to test my own version of the double ridged paddle soon and report on results.

Read More..

Paddle Design Prologue

Ive had two different prototype paddles kicking around for a while that I was not able to get to the point where I liked them.  What I typically do when I build new paddle designs is to overbuild them and then whittle away at them until they work to my satisfaction, or at least until their performance does not improve any more. Sometimes, it is just not possible to rescue a paddle design.  I have to walk away from some paddles and simply write them off as a learning experience. I generally have no idea how a new paddle will work until I actually try it out.  I would like to say that the more paddles I build, the better I get at predicting paddle performance, but I would be lying.  The only way I can tell what design will work is to actually build it and try it out. 

 

I should also mention that a paddle must be matched to the boat as well as the paddler to perform well.  A paddle is not a good paddle in the abstract.  A paddle is a good paddle only for a specific set of conditions.  In this case, I happened to have my King Island kayak readily available and that became the test platform.  The King Island kayak was fairly well suited to this particular paddle test because the King Island kayaks high deck calls for long paddles and the set of paddles I was testing were fairly long, 98 inches.  I had already modified both paddles based on previous tests. One paddle had started out at 102 inches long and I cut it down and the other had a loom that was way too fat for comfortable use and I had slimmed down the loom on it.  The thing about the fat loom was that it felt good in the shop, but out on the water in action, it was just too bulky.

Heres a shot of the inside of the King Island kayak. Note the high deck ridge.  The thing about a high deck is that it forces you to hold the paddle up higher which means that it has to be longer to reach the water.

And here is a shot of the two test paddles on the deck of the kayak.  The lower paddle was based on a paddle shown in an old illustration. The upper paddle is a breakdown version of a more conventional Unangan shape except for the loom.

Both paddles are versions of an Unangan (Aleut) design. The Unangan paddles are asymmetrical with the loom offset from the plane of the blades. 
And so I had my test paddles, test boat and test pond, San Francisco Bay.  Even though I had whittled away at both paddles and tried to improve their feel, I preferred the one piece paddle because it was lighter and seemed to move the boat with less effort.  The breakdown paddle felt heavy and more ponderous in the water. 
After the initial test I did a little more whittling and then took out both paddles again and this time I had my GPS with me.  The GPS gives me a speed readout which I can use to measure top speed for a boat or paddle and if I have two or more paddles, it gives me top speed for comparative effort.  Effort expended is pretty much a subjective measure but on a given outing, swapping paddles back and forth several times gives me a pretty good idea of comparative efficiency of two paddles.
And this is where the GPS comes in.  Although one paddle may feel better than another the one that feels worse may actually be giving me a better top speed. It may feel worse because it moves more water and makes me work harder.  But if I am simply cruising, comfortable feel of a paddle may be more important than top speed. Comfortable feel may also be an indication of better efficiency of one paddle over another. 
So to sum up, paddle design for me is a pragmatic exercise.  I have to test paddles on the water to tell whether they are any good and results are often surprising.  In a future blog, I will get more specific on factors that make for a good match between paddler, boat and paddle.

Read More..