Rudders are different
Holes could reduce stalling and let teh rudder maintain grip at extreme angles.
…because of surface area!??..
NO, you’re incorrect. The density of deeper water is greater, thus…the face of the paddle blade has more resistance acting on it at depth…and the paddle is “working” with more leverage at more depth. Just for starters…
$.01
Okay, so why not…
– Last Updated: Feb-24-07 5:52 PM EST –
... just poke a dowel rod down there and paddle with that? You still need surface area. You are right that the deeper water provides greater resistance and bite but it's not due to higher density (simply dropping the water temperature from 70 degrees to 40 will increase the density hundreds of times more than you can get with an increase in depth which is many times the reach of your paddle, but even that increase in density is miniscule and you'd never feel it, so density is not the issue here. Remember that water is for all practical purposes non-compressible? That means you can't easily squeeze it into a smaller volume). Instead, the water a couple feet below the surface is more tightly confined by the weight above it and is less able to spill and swirl than water right at the surface which is has less confinement weight), but that doesn't mean you can do without having a similar surface area with which to get a grip on the water. I'm sure there's even more I'm leaving out, but since I was only commenting on what Grayak wrote, maybe take it up with him as well.
I’ll leave the intellegent answers
– Last Updated: Feb-24-07 9:20 PM EST –
to you intellegent sorts. I would only drill a hole in a paddle to stop a crack or split. Worries about resulting hydrodynamic innefficiencies would be remedied with duck tape or a band aid. The innuit or greenlanders would never even know. Or care. Golf ball type dimples in a paddle or hull could maybe reduce turbulence of a solid moving through liquid? Not my idea, I read it somewhere.
All wet on that one!
One of water’s odd/interesting qualities is that it is nearly incompressible.
This is why water fire extinguishers need air in them that can be compressed and then expand to push the water out. It’s why subs use air or other compressed gasses to “blow ballast”. A diver may need a phone booth worth of surface air to fill his lungs at depth - but a lung full of water at same depth is just a lung full at surface. A ball filled with air will compress with depth - and re-expand when surfaced - but a water filled ball will not. It stays the same.
PRESSURE changes with depth, but density changes VERY little . Temperature and salinity are the primary density variables.
The immediate surface layer - often down to several feet (sometimes hundreds) is most commonly a mixed layer without much difference in these values.
At least that’s what I recall from my oceanography classes, salinity and bathymetric readings I took in various parts of the Worlds oceans, anti-sub warfare stuff, etc.
Yup - keep it simple, skip the dimples
Dimples aren’t good either - for hull or paddles. Need different velocities and lower viscosities (water too dense - kayak too slow) fro that sort of fluid mechanics.
Good stroke techniques hardly move the paddle blades through the water at all. This is not intuitive to most - but I’ve looked at stop motion images of this, and now not it in my own paddling. Blade motion is mostly the up down of catch and release and the tilt of the lever action of the shaft. There is also the added small sideways motion of wing type strokes (and similar flying of canted blades) - that keep the the blade face moving into clean water and the single vortex* behind and slightly trailing. Blade is kept between high pressure on the face and lower pressure on the backside - which reduces slip/adds bite/creates a lift force forward (depending on how you like to look at it and what terminology you prefer).
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- Note: vortex forms from pressure difference on either side of loaded blade - not speed of blade through water - (unless you’re tied to a dock and paddling in place!).
- Note: vortex forms from pressure difference on either side of loaded blade - not speed of blade through water - (unless you’re tied to a dock and paddling in place!).
tell me this, does more bite equal
more vortex?
doesnt bite come from the interplay between water and the outside edge of the paddle, e.g. bite is created when the paddle moves through the water right? a planted paddle generates no bite right.
if you measure the length of the edge of the blade many GPs have more edge than EPs and theoretically should have more bite…my layman’s view of bite is that it exists because moving water does not like to turn an edge, sine the GP usually has more edge (agreed the amount increases from the beginning to end of the stroke)it should have more bite than an EP…the EP gets more paddle face/edge in the water quicker than the GP, that’s why it has more power initially but I doubt it does by the end of the stroke…so GP users wanting more power should practice getting more of the blade completely in the bite zone quicker…
Now on drilling holes…reminds me of the paddle the principal used on my behind…more holes in a paddle blade should equal more bite right? since more edges for the water to have to curl around???
has anyone ever tried
With all the super materials we have available, has anyone ever made something like a hoop paddle? It would be a paddle with kind of like tennis racquet ends, but instead of strings, a very light, resilient, impermeable cloth or plastic. And it would form a very shallow spoon when it was being paddled. The hoop or edges would of course have to be much thinner than a tennis racquet. Only good for lakes/ocean, probably not tough enough for river use. Probably pretty light. Don’t they make a raquet like this for beach use, beach paddle ball?
Remeber rocket fins?
Jet fins and Rocket fins sold a bunch of fins to scuba divers with this smae concept. They were designed with vents in the power face to allow some water to flow through the fin.
While I am not prepaared to drill holes in any of my paddles just yet (even the failry small 25mm ones discusssed here), I am interested in seeing more data.
More bite = less slip
Better traction. Not really an edge thing that I see (if I understand you). More about simple drag, and some manipulation of the low pressure area though shape and technique.
Edge and attack angle can be looked at for vortex size/shape to - but since different shapes can have the same area it may be more interesting to look edges as they relate to catch/release and other paddle handling qualities.
As I said elsewhere, paddles pull through the water a LOT less than people think. Acts more as a lever once you are moving, and more so as speed increases. Longer narrower blades probably do allow more control of the lever action.
Technically less slip is better, but real world some slip prevents us from overworking engine or blowing a transmission. Mixed mode. Blades have to work over a range of slipping, levering, and all other sorts of motions in control strokes. All paddle designs are compromises - by necessity. Wing gives up some generality to get more bite, etc.
Have to match/balance things. Most paddlers just back off - altering power and cadence to handle the extra bite they might want for sprints. The other option is to adjust paddle size and maintain form/cadence that results in best aerobic output for a given paddlers power and endurance over distance, using cadence/power changes to sprint.
Being variable ourselves, most just adapt to and use what’s available, popular, standard, etc. Works well enough. Still sort of funny how much folks will obsess about hull design/speed in comparison.
When looking to alter/adapt/innovate - it would help to start with the major variables - and decide on priority/focus - rather than just going after some generic improvement from holes, dimples, etc.
I had a pair… Sea Hunt era…
I think Scuba Pro… they were wide, short and heavy. I was so glad the day I lost one L. The newer ones were lighter, longer and much more flexible.
see’ thats what smokin’ that stuff…
I was thinking of some stratigeic dimples along the hull of one of my yaks or air bubble channels fed by foot peg/pumps. FAR-out Eh
What about the idea
of having a membrane stretched over a hoop (like a drum) as the ends of paddles? Seems like it would form a “spoon” while paddling, would flex a little. Has anyone seen/used a paddle like this?
What a concept
Maybe this thread will make it over to the Majors. Someone may put 2 and 2 together.Imagine the homeruns that could be hit with a wiffle bat.
I know apples to oranges right
Helmet like a golf ball?
That would be interesting-looking.
Re: Holes in paddles
Seems to me like the more surface area that you have on your paddle, the faster you glide through the water. The surface area pushing against the water is what pushes the boat through the water afterall.
I’m not a scientist and this shall not be considered scientific data! 