Paddles or Propeller
In another article, I offered the choice of Bike or Trike.  This time, it’s Paddle or Propeller.  Again, you’ll be wondering what I’m talking about.  Am I suggesting fitting a battery + electric motor + propeller and setting off for an easy paddle, a bit like an electric bike?  Actually, that’s the basis of an article on its own, don’t you think?   I know it has been done already, and I’ve always had the notion to fit my own electric propulsion, for racing so that I can get back to my winning ways.  The only snag is, how to get the boat in and out of the water without casual observers spotting the propeller.  I think I could manage that for the Oban race round Kerrera, then surprise everyone with my speed and endurance, despite advancing years.  I was working in Oslo a couple of years ago and amazed how fit all the old folks were on their bikes, whizzing along the myriad cycle paths which proliferate in the city – we should have that in this country.  Then I spotted most of them were ‘electrically assisted’.  Ah!
When boats were built many years ago, sail and man-power (and women sometimes I guess) were the only sources of propulsion.  Then someone invented the paddle-wheel.  Finally, the propeller came along, and paddle power became a thing of the past.  We are just managing to hang on to the Paddle Steamer (PS) Waverley these days.  I’m a great fan and have been a member of the PSPS for many years.  You should join.
Back to the plot: the propeller is so much more efficient than the paddle, and yet we kayakers and canoeists are stuck with paddles… or are we?  At this point, I’m going to drop the canoeists, (please forgive), and stick to two-bladed paddles.

   
In kayaking we had that same Eureka ‘propeller’ moment almost forty years ago, when Stephen Lindberg invented the ‘Wing’ paddle.  The Swedish team took up the challenge of adopting the new design, and did very well with it at World Sprint events.  Soon everyone had adopted this new shape, and times dropped by at least 2%.  I remember having my first try in the 90s, and because I knew my speeds pretty well then, and now, I can say with certainty, that within 10 days I was going faster than before.  Since then I’ve never looked back, and wouldn’t dream of returning to the old flat, asymmetric blades, so beautifully manufactured by Lendal Products in Prestwick.  Incidentally, the asymmetric blade was a step forward too, and much appreciated at the time – the idea being that the whole blade entered the water at the same time, rather than the leading edge, thereby reducing a twisting torque on the shaft.
That’s Iain Speirs holding a 90-degree feather, asymmetric Lendal paddle along with, from left to right, 
Alistair Munro, Bruce Beeley, Iain Speirs, Peter Turcan, and the author – looking a bit younger and fitter than he does now.
How on earth someone worked out how to design such a stunning paddle defeats me.  Can you imagine the trial and error with different moulds?  Engineers fill me with admiration.
But what’s this about the propeller you ask?  Well, the ‘Wing’ paddle actually makes use of the same forces as a propeller, and has other advantages too.  A normal traditional paddle simply pulls water back and it spills over either side inefficiently – just like a paddle wheel.  The ‘Wing’ paddle does that for sure, and most of the power comes from that basic principle, but the extra +2% comes from the Bernoulli effect on the blade.  There’s so much to say about the Bernoulli effect on kayaking, I’m going to make that my third topic in this series of articles.  So let’s just look at the Bernoulli effect on the Wing paddle for a moment. 
Without going into too much detail, the flow of water over the back of a propeller and the back of a ‘Wing’ blade is not the same as the flow of water over the front of the propeller, and the blade.  This creates a differential pressure so that the pressure behind the blade becomes less than the pressure on the front of the blade.  Think about it for a moment.  What that means, in very simple terms, is that your blade is being forced forward by the differential pressure, which is exactly what you want.  That’s what makes the ‘Wing’ blade so efficient.  There’s something else too which happens: the shape causes the ‘Wing’ blade to move out more as you pull it back, accentuating the differential flow of water over both surfaces and making it behave a bit like the wing on an aircraft, using the same Bernoulli effect to produce lift.  So, if the ‘Wing’ is properly designed, and that’s not always the case, your paddle stroke also gives you support, which is so important in terms of stability.
Of course, after the introduction of the first ‘Wing’ blade, everyone and their aunt set about copying it, without infringing copyright.  I don’t know the ins and outs of that, but I do know that there were many variations on the theme all these years ago and still are.  So, you are asking me which make is best, and which do I recommend?  I can’t tell you.  All I can say is this:  you want to be sure that the paddle gives some lift (not all do) and that it enters and passes through the water with minimum disturbance.  My blades are so well made that they do not draw down any vortices or bubbles at all when pulling at moderate speeds.  They are almost totally silent and sweep through the water in the most beautiful way.  I often look down at the blades when I’m cruising along gently in the crystal-clear waters off the west coast of Scotland, and marvel at the perfection of their design.  One word of advice though: don’t ever damage the ends of the blade.  I’m OCD about that.  As soon as there is a bur on the blade it loses that ability to sweep through the water undisturbed.  Who would put a rough edge on the front of an aeroplane’s wing?  That would be very silly.  So it is with wing paddles – don’t knock them on the rocks, and if you do, repair them immediately, or buy a new pair with metal tips, which are much more robust.
Any other pros and cons?  Yes.
I find Eskimo rolling OK, although not so easy as with the older flatter blades. And because of their curvature, ‘Wings’ work much better rolling on one side than the other.
What about length?  Suit yourself.  Buy them with adjustable length and establish what suits you best in different conditions – rough and smooth.  I’m working at around 210 cm at present, but for fifty years I’ve had no idea how long my paddles were – I had to measure their length when writing this for you.
What about feather?  In the old days, we paddled with an extreme feather between 80 and 90 degrees, to reduce windage.  But that presents all kinds of problems with wrist movement.  One of the many advantages of the wing paddles is that they deflect the wind much better than flat blades.  Take care though, in very windy conditions they can catch the wind like a real wing, and flick you in.  That’s why many serious sea kayakers avoid using them, that, and damage on the rocks when landing or embarking from rocky shores.  I’ve moved down from 90 degrees to 50 degrees over a period of 50+ years, and much prefer the new setting.  Again, experiment with two-piece paddles, which you can adjust to your liking. 
Finally, don’t get stuck in your ways – embrace change; experiment.  Why not?