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.