Sit Up and Take Note

Sit Up and Take Note

Can simply sitting up during your stroke make the boat go faster?

All dragon boat paddlers know that when there is movement in the boat, there is an effect on the boat. Sometimes this movement can be used for good. Sometimes for evil.

Rowers, with their sliding seat, experience an effect on the boat due to their body movement as they slide forwards and backwards through the stroke.

A previous, fairly detailed Dragon Analytics post covered how movement of bodies within the boat affected the speed of the boat. Read it for a more mathematical view of the topic. This post will give you an idea of the concept.

Some dragon boat coaches encourage a pivoting at the hip as part of their technique. This shifting of a paddlers' bodies backwards and forwards has an effect on the speed of the boat.

With proper use of body weight, pivoting can be used to propel the boat forward. The video links show body movement being manipulated to move a canoe skate board forward. Imagine the effect of 20 bodies moving in unison in a dragon boat!

 

In dragon boating, the action of sitting up as part of the driving force actually adds to the forward motion of the boat. A movement of weight backwards creates a movement of the boat forwards. A movement of weight forwards creates a movement of the boat backwards. This is called Conservation of Momentum.

Ideally we want to take advantage of one half of this phenomenon - we want movement of weight backwards to add to the speed of the boat forwards. But we don't want to then create a slowing of the boat when we move our bodies forwards in readiness for the next stroke. So how can we break the Conservation of Momentum law? Bad news. We can't.

The secret is to try and manipulate the movement of the body or bodies forwards in such a way that the tendency to slow the motion of the boat is minimised.

The people in these videos propel the board forward when driving backwards. However, according to the law of Conservation of Momentum,  they should also propel the board backwards when rocking forwards on the return. But they don’t. Why?

Because they drive back fast but return slow. By returning slow, friction and inertia "absorb" the force that would normally drive the board backwards.*

If they had driven backwards and forwards with the same gusto the skateboard would roll forwards and then an equal distance backwards.

The same technique could be applied to a dragon boat stroke. If one could manipulate the return to minimise the effect of the slowing force, then one could foreseeably gain some advantage by sitting up as part of the driving force.

Remember. The aim is not to minimise the slowing force because we can't - it is a law of physics (Conservation of Momentum). We are trying to minimise the effect of the slowing force on the boat. Just like the people have in the videos.

If any of our readers have experimented with this phenomenon, we would love to hear from you.

 

*  This analysis is interesting but simplistic because there are many other factors to be considered when trying to propel a craft through water.

10 responses

  1. Interesting…

  2. Hope everyone sees this.

  3. Do it all the time!!

  4. Very interesting and different from our stroke.

    • Mark Fogliani

      Thanks Patricia,
      Yes it may well be different from your stroke. And to be honest, I am not yet 100% sold on the idea that we can get the pros without the cons. So let’s call this idea work in progress until we get some hard data.

  5. Exit is too far back, in my opinion…and the paddler seems to be pivoting around the bottom hand, which bleeds off thrust far too soon…..again, in my opinion..

    • Mark Fogliani

      Hi Mike,
      Thanks for your feedback. The graphic’s main purpose was to show the movement of the paddler’s mass during a stroke. The technique depicted has some flaws (some of which you have highlighted) which I will address in future posts. Well spotted.

  6. It’s very difficult to accurately criticise the stroke here when there isn’t a paddle to be seen. Core strength and leg drive through the stroke should lever the body up and back and I for one believe that rotation through the stroke lengthens the positive angle of the blade at the back of the stroke too. Acceleration at the back of the stroke is quite possible but I have yet to actually prove with our crew that it is a helpful technique in races.

  7. Hi I do find this interesting as it ties in with my thoughts on recovery! I’ve been experimenting with various aspects of the stroke cycle over several years & more recently on recovery speed. For example the effects on energy & power during the stroke cycle and ultimately on the run of the boat.
    I’d agree with a slightly slower recovery than a snappy whipping the paddle forward as it does seem to effect the run of the boat somehow. Slowing recovery didn’t slow speed… but you need a strong pull through. Essentially it allows your energy to focus more power at the catch & pull through, thus a more fluid stroke with ‘recovery’ for the next stroke, therefore could be more energy efficient for the paddler and with this concept in mind, with the boat too!
    Obviously there are so many variables to consider such as technique (major factor) boat craft & conditions etc. I’ve spent many many many hours experimenting with technique & speed with data gadjects in my 01 (training outrigger kayak) and also monitoring them in the dragon boat. I encourage only technique in my outrigger boat…. well as close to a dragon boat stroke in single boat as possible, which does seem to get very similar readings. Bearing in mind the varying factors in weight of the boats etc…etc.. Furthermore, I single scull (& sweep row) and this initiated some of my thoughts about how vessels run on the water… one can learn a lot from a bow wave!
    Many thanks it’s good to see people take interest in developing our sport.

  8. Lee

    Looks like a C1 stroke and posture. Those boats are super light and a slow recovery is what they need to maintain as much as possible. Dragonboats are heavy and don’t lose momentum like a C1, so the more efficient way to maintain glide is to be short in the air and long in the water, the opposite of what was demonstrated here. My 2 cents of course but that’s what I see.

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