Effect of Dead Weight in a Dragon boat

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Image provided by Broadwater Dragons http://www.broadwaterdragons.com/

What is the effect of dead weight (weight you do not need) on the performance of a dragon boat? Many dragon boaters bring bottled water into the boat or wet themselves down on a hot day before jumping into the boat. It is obvious that this adds weight in the boat.

What is not so obvious is the effect this extra weight has on the speed of the boat? Is it worth worrying about? 

What will be the “cost” of this extra weight?  

Firstly, we need to know the relationship between boat speed and dead weight. Fortunately our scientific friends have worked this out already. *

The change in dragon boat speed is equal to -1/6th of the additional dead weight. 

Let’s look at some common scenarios.  

Example 1:  Effect of Water Bottles on Performance

Let’s assume a full dragon boat weighs 2000kg (20x80kg paddlers + 60kg drummer + 70kg sweep + 270kg boat and oars and drums).

Every paddler brings in 200mls of water (0.2kg) which equates to 4kg (20 x 0.2kg) of dead weight. 

The extra 4kg obviously increases the overall weight of the dragon boat and crew. This equates to 0.2% increase in mass.

So using the formula mentioned earlier in the post, the boat will move 0.2%/6 = 0.033% slower.

0.033% is a small penalty, right?

Over a 500m race normally taking 2:30 this extra weight will add 0.033% to the time. This equates to an additional 0.05 seconds. Five hundredths of a second. That doesn’t sound like much.

How about we look at it from another perspective. If you compare the same crew with water bottles and without, the boat with water bottles would lose by 16.5cm. 

So the short answer is that there is an effect caused by the additional weight and it can be significant in a close race. 

Example 2: Effect of Weight of Drummer or Sweep on Performance

Let’s assume the same full dragon boat, but now the drummer and sweep are each 5kg lighter. In this example the drummer and sweep are considered dead weight (don’t tell them that). 

The 10kg weight loss equates to 0.5% decrease in mass. So the boat will move 0.5%/6 = 0.083% faster.  

Over the original 500m race time of 2:30 this corresponds to a decrease of 0.125 seconds or winning by 42cm. 

So the takeaway here is that the weights of drummer and sweep have a significant effect on boat speed. 

Example 3: Effect of Water in the Boat on Performance

What about water in the boat? Should we bail it out? 

Let’s assume the same full dragon boat but now there is water in the bottom of the boat.

Let’s say the water covers benches 3, 4, 5, 6, 7 and the water depth in the boat will be from 0cm at the front to 2cm in the middle and down to 0cm at the back. That’s an average of 1 cm deep across 5 benches. Assume 1m between each bench and the average width is 0.6m.

Image provided by Photographer: Zhao Haoxiang

The volume of that water would approximately be 4m x 1.0cm x .6m = 24,000 cubic centimetres. 24,000 cubic centimetres of water is equivalent to 24 litres which is equivalent to 24kg. 

The 24kg weight gain equates to 1.2% increase in mass. So the boat will move 1.2%/6 = 0.2% slower.  

Over a 2:30 race this corresponds to 0.3 seconds or 1.0m. 

Of all the scenarios, this one shows the largest effect of dead weight. Losing a 500m race by a metre because there is 2cm of water in the bottom of the boat is inexcusable.

Summary

Dead weight affects the speed of a dragon boat – whether you gain it or lose it.

Keep this in mind the next time you step into a race boat. Minimise any dead weight, including water in the bottom of the boat, water bottles, wet race shirts, etc. 

Like most sports, dragon boating is full of “1%”s. Managing weight is only one of the ways to get incremental improvements in performance. It costs nothing. What have you got to lose?

* If you want me to write a post on where this formula came from, please leave your request in a comment below.

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