How can holes in a blade make the boat go faster?

Oscar Blade

Oscar Propulsion logoOnce in a while something special comes along that looks set to transform the sport of rowing. The Oscar BladesTM is a radically new blade design for sculling and sweep oars which mimics how elite swimmers now swim faster with their fingers spaced apart. It is now undergoing on-water time trials and more than matching the 1% to 2% increase in boat speed predicted by computer modeling.

Oars and paddles operate by creating a pressure difference between front and back surfaces of the blade, so generating drag. However, high-pressure backflows from the front of the blade into the low-pressure area at the back of the blade reduce this pressure difference and limit the thrust generated by the blade. This reduces the potential velocity which the boat can achieve.

Oscar BladesTM consists of multiple, narrow (0.5mm) slits through the blade which creates solid “fingers” between them. These slits, or PowerSlitsTM as they are known, generate focussed water jets to counter backflows behind the blade and so increase thrust. The “fingers” produce the drag which propels the boat.

Oscar Blades, with PowerSlits, fast rowing oar, sculling oars,
Oscar BladesTM  with PowerSlitsTM

Oscar BladesTM currently have the same shape and profile as the Concept 2 Big Blade. PowerSlitsTM technology can be applied to any blade shape.

The Proof of the Pudding: On Water testing at Peterborough RC

Volunteer rowers, including the heavyweight sculling team from Peterborough RC, have been trialling Oscar BladesTM since April 2018 to prove their performance. Their trials have shown consistent, winning time advantages, over 500m at full pressure, of 1 to 2 seconds.The trials were carried out according to the Concept2 protocol of 6 x 500m timed pieces rowed at full pressure, supervised by an independent coach.

The rowers report that pulling the blades is noticeably lighter and more enjoyable. This allows them to comfortably increase the stroke rate.  However, trials at fixed stroke rates, as shown in the graph below, have also shown a speed advantage. So we are convinced that the speed advantage comes from a combination of higher stroke rate and increased thrust. The added benefit of the lighter feel helps the rower to work harder.

rowing oar speed test, faster rowing oars, oscar propulsion rowing oar
Results from one of the Peterborough RC trials, rate capped at 26 strokes/min

 

David Taylor invented the Oscar BladeTM while rowing competitively for 3 years in his college team and studying engineering. Whilst pulling hard on his oar he observed the “bow wave” at the front of the blade and the “dip” in the water at the back. Clearly, there was a pressure difference and the thought occurred that joining the two sides with holes could make pulling the blade lighter without loss of thrust, providing the holes were small enough.

If it worked, it would make rowing a little more enjoyable whilst enhancing the sport.  Putting holes in a perfectly good blade seemed counter-intuitive at the time, but a recent project carried out for Oscar Propulsion by Southampton University has since proved that the Oscar BladesTM with their PowerSlitsTM really do work.

We have patented the technology and now want to make it available to every rower.  Provided manufacturers adopt the technology, sculling and sweep oars could be available to rowers around the world in 2019.

Like to be part of the Oscar Revolution? Test Pilots required.

We need to carry out more testing with different rowers to cement our positive findings to date, so we are looking for more volunteers to help test the Oscar BladesTM. We would welcome more sculler volunteers to test them, initially in the UK and then internationally.

If you would like to be an Oscar Test Pilot or to find out more about Oscar BladesTM, please contact us at info@oscarpropulsion.co.uk or call David Taylor on 07784042680

Website: oscarpropulsion.co.uk

Oscar Propulsion
Oscar Propulsion

 

2 thoughts on “How can holes in a blade make the boat go faster?

  1. Peter Jago says:

    An interesting development! I had noticed how swimmers used an open hand on the pulling part of their stroke, which can be seen on TV coverage of international swim events. After watching UTube and FB coverage of the Romanian 8+ at HRR and Robbie Manson at Lucerne rating high (40s) all the way over a 2k+ course, as well as listening to Martin Cross’s comments about the current trend, this development has interesting consequences. I would like to see trials over 2k for both 1x and sweep oared boats and work out the advantages/disadvantages and use for both boat types over both regatta and Head race courses. Happy to experiment!

  2. david taylor says:

    Peter

    Thanks for your comment and sorry for the delay in replying. We started our trials very tentatively so that we could understand how the Oscar Blades perform on water: would they be strong enough and would we see the actual time improvements that the computer had predicted? They are certainly strong enough. To date the highest we have rated over 500m has been 32 carried to by Ben Rodford a couple of weeks ago. Ben was 3 to 4 seconds faster during his 4 runs using the Oscar Blades when compared to the same blade without the PowerSlits. He actually got faster as he became accustomed to the lighter feel of the Oscar Blades.

    What we have observed over the 14 trials conducted to date is that the time difference increases as rate increases. We would now like to run some trials at higher rates, at least 34 and progress to the 40s and plot the trends. We mirror your interest in what might happen and are optimistic about seeing some very interesting results.

    We would be very happy for you to conduct the experiment. Could you call me please on 07784 042680 or email me at david.taylor@oscarpropulsion.co.uk and we can set something up.

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