Subject: RE: baidarka Aleut Paddle - my version
From: LEW PLUMMER (jayhawk@sos.net)
Date: Wed Dec 20 2000 - 04:30:57 EST
We really want to thank George Dyson for collecting and sharing the original
tracings of the grooved Helsinki National Museum Paddle. My contribution
has been the CAD drawings and subtle shape and length adjustments to fit my
continually evolving paddling technique. Or, viewed from the opposite
perspective, the continually evolving paddle shape that continually effects
my paddling technique. James is really the one who has contributed the most
energy and enthusiasm required to fully understand the subtleties of this
historical design.
The shape of the blade edge just about defines the way most paddles work.
Rounding the edges will produce a soft stable stroke with more slip, while a
sharp clean edge produces more lift with reduced stability depending on the
designed face angle. A 1x4 flat board pulled it through the water with
enough force will flutter so will just about any paddle. The point of
flutter probably coincides with the maximum amount of lift that any
particular blade design can achieve. The amount of flutter seems to be
inversely proportional to boat speed - faster less, slower more. In most
cases it's just a matter of how much force the paddler applies per stroke to
get up to speed.
A couple of years ago James and I headed for Puget Sound with many paddles'
in hand for the express purpose of comparing their virtues. At that time
James had produced a near knock off of one of my favorite Aleut paddles (the
one I used in Sea to Ski last year). The major difference between the two
was his power face was ridged mine was grooved. If I remember correctly the
92" grooved paddle (dubbed "my favorite") was decreed the best of the bunch
while the ridged paddle was a very close second. The face angle of the
grooved blade was only slightly flatter than the ridged blade. The effect
of shape can be so subtle in these cases that it makes it difficult to
compare designs. As for the groove; don't know what difference it could
make, maybe it's not the groove but the fact that there are two ridges or
dams that could slow water flow over the blade face which may increase lift.
Note: We used a GPS to gather speed information during our informal tests.
Some observations in using Helsinki Museum paddle copies:
1. The submerged blade edge is progressively increasing through the stroke.
I would start my trunk rotation late with this paddle because there was lots
of bite at the end of the stroke when the blade was almost fully submerged.
2. The broad "X" artwork on the blade may be a gage; it seems to define the
optimum blade entry angle and the point of immersion to start the power
portion of the stroke. Experienced paddlers seem to hit the "X" with every
time.
3. The short loom requires that you rotate your trunk to achieve the best
stroke effency - it makes you use more muscle groups; as well it should.
I think one of the major paddle design considerations should be weight and
polar moments there is nothing more fatiguing than a heavy paddle with heavy
blade ends. My favorite grooved Aleut paddle was made from second growth
Western Red Cedar and it weighted just under 24 ounces (I didn't use it for
boat access/egress). I used it for three years before it separated from my
truck and shattered on the road. It was not at all flimsy in the water even
though I removed as much wood from the blades as I dared in an effort to
reduce tip weight. Red Cedar has a tendency to split but it is easily
repaired with foaming urethane "Gorilla Glue".
When designing my first paddle I started with a roughed out blank piece of
Sitka Spruce and did much of the shaping while sitting in the kayak. This
thing started out 110" long and 4" wide with a 33" loom; it was a hunk. One
iteration was 102" long and three inches wide, round backed, sharp edges a
nearly flat face, slightly cupped tips and a single ridge. I wanted as much
blade edge as I could get on this "stick" as my buddies called it. This
seemingly tiny paddle blade possessed a huge amount of lift and an
incredible amount of flutter. I softened the edges and it became more
manageable but the lift was significantly reduced - not good. I increased
the face slope and tried it again; result -- less lift. I re-sharpened the
edges and the lift was back and the flutter had diminished. The back of
this blade was very rounded right up to the sharpened edge more tulip
shaped. This seemed to maintain laminar flow off the edges and part way
around the back this might have contributed some extra lift. My Aleut
paddles tend to follow this edge design to some extent. The drawings on the
WEB page reflect the original Aleut design the images reflect my subtle edge
design change. It was an interesting exercise and I used "the stick" for
many happy miles but I think there are many ways to accomplish good paddle
characteristics, just about as many ways as there are paddlers so much of it
is what we get used to. Some blades do, however, seem to have more speed
potential than others, the modern wing paddle is a good example.
The wing blade requires a very precise motion through the water to achieve
optimum efficiency; it is made to fly in the water rather than just push
against it. It's great for racing but as an all around blade it has some
shortcomings. Greg Barton indicated that there is about a 2% increase in
effency when used correctly. My heart rate will raise (indicating increased
effort) and my boat speed will decrease if I don't maintain good technique
with the wing blade. What this means is; simpler blades are more forgiving
and more versatile for over all kayak use. The general design of the long
Aleut blade is arguably one of the best in my opinion.
I have rambles on and on Merry Christmas
Regards, Lew Plummer
-----Original Message-----
From: owner-baidarka@lists.intelenet.net
[mailto:owner-baidarka@lists.intelenet.net]On Behalf Of James Mitchell
Sent: Tuesday, December 19, 2000 9:18 PM
To: baidarka@lists.intelenet.net
Subject: Re: baidarka Aleut Paddle
I already done did the scooping. That's what the shaper is for. The power
face is essentially done.
Now.... OK, that's a maybe. The "Maybe" is if you want to accept my "short
cut" ridge shape for now. I have stopped making the ridge as sharp as I
used to. I am going now for a rounded ridge that is more the resultant size
of the grooved ridge that Lew uses on the center of the paddle. You can
take my blank, round that ridge down to Lew's dimensions, and with a narrow
gouge put in his center groove. Or you can do what I am doing, just round
that ridge off.
Performance wise, I think the rounded ridge is fine; at least within our
ability to test so far. We are doing more tests to try to determine the
real function of the ridge at different angles of attack. I have found that
the sharp ridge may be a contributor to flutter, whereas the rounded ridge
seems to draw less critically.
Lew's grooved ridge seems to perform just the same as the rounded ridge.
Lew thinks (and I am not disagreeing; but have no evidence either way yet)
that the center groove adds power to the stroke. I dunno. I do know that I
am really pleased with the rounded ridge that I have been using. It seems to
make the paddle especially friendly in a low brace, where it skims the water
gracefully. In a high or sculling brace, the paddle seeks its own proper
angle of attack. That is very sweet in practice. Lew and I agree that my
blade pulls a bit more smoothly than his, with considerably less flutter --
due largely, I think, to the dihedral angle; however it is possible that the
ridge is affecting flutter. It is hard to compare actual pulling force
without some objective measuring gear. Bottom line: Lew is one hell of a
speedster; he can pull away from me any time he wishes, using either paddle.
AND now that we have finally got ourselves all nice and comfy, I dug through
David Zimmerly's web site and extracted a large copy of the MAE hulls
(Lenningrad) from Akun, collected about 1845. Both drawings show a
similarly shaped Aleut paddle, a variation on the blade that Lew drew up and
that we have been making and testing. These blades are slightly longer at
100" (250-254cm), and about 3-3/4" width. The blade portion appears to
average about 39", as opposed to our present 33". The loom may be 2 "
shorter, running about 22" to our present 24". Result: a monster blade. I
made a template last night. This blade will fit the same shaper setup as I
am using for the present Aleut paddle, so I will make one from a couple of
the clear 2x6's that I picked up at the lumber yard a couple weeks ago. This
one may pull my arms off, we shall see. But what we may have here is a
really high power Aleut blade. I am calling this one the Akun blade. Lew,
if you are listening, do you know where your blade came from? Can you tell
us more about that?
Dotter1.com, the Juneau Jewel, has apparently joined the kayak club up
there. They have been drooling over her boat, and asking paddle questions.
So she is getting my latest Aleut paddle for Xmas. If you are around Juneau,
this will be a chance to try the blade. I will be there from the 22nd to the
29th, so if you want to come talk kayaks, I will meet you at Valentines any
day I am not skiing!
----- Original Message -----
From: "Samson Family" <bill.samson@tesco.net>
To: <baidarka@lists.intelenet.net>
Sent: Monday, December 18, 2000 8:00 AM
Subject: Re: baidarka Aleut Paddle
> -----Original Message-----
> From: James Mitchell <mariner@seanet.com>
> <snip>
> >All you
> >will need is a low angle block plane, or a good belt sander.
>
> Will that be adequate to generate the scooped out bits either side of the
> ridge? Or will some kind of rounded-sole plane be necessary?
>
> Bill
>
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