Behind the Line – Are There (enough) Coconuts?

In this coconuts post, there isn’t a ‘line’ I can quote yet as this research topic is taken from the next Emma Sharpe adventure, which is status=in progress.

#TDTPiratesWentMad - Are There Coconuts?
Photo credit: by Nandhu Kumar, CC0, via

This time Emma and Jack begin their adventure cast away on a deserted island. Their first challenge? The lack of potable water.

  • According to the Rule of Threes, humans can survive for about 3 days without water. After that, the ability to concentrate and undertake physical effort begins to noticeably degrade. A good rule of thumb, perhaps, with reality dependent on the conditions of the situation.
  • Here’s another way to look at it: to stave off a net loss of fluids in the body through evaporation (sweat, breathing) and more direct functions like urination, a typical human needs to consume at least one litre of water per day.

So, what do our heroes do?

  • Solar desalination or distillation – There is seawater in plenty and the air is humid. They do have their clothes, a knife, and some vegetation available as resources. It might be possible to create some sort of improvised solar still, but the amount of water that would be generated is unlikely reach two litres per day, or even half of that.
  • Digging a well – The island does get rainfall, and in fact the preceding weeks have been wet. However, the island is rock with the occasional pothole of accumulated dirt. So even with the right tools and plentiful labour, digging for water could still fail. And Emma and Jack do not have time to develop Stone Age boring tools.
  • Eating your fluidsFruits and vegetables contain a lot of water. Raw meat and fish are also 70%+ water. Emma and Jack also need to eat, so could they ‘kill two birds with one stone’? There are (shell)fish in the reef but there aren’t any vegetables or fruit on the island, except for a few coconut palms…or are there? Sounds like an assumption that needs to be checked.


The story takes place in the West Indies – a land synonymous with coconut palms swaying in the breeze, right? Surprise – coconuts are not native to the Caribbean. However, fortunately (for my plot), at the time Emma is having her adventures they could be found in the region.

It’s thought the Portuguese and Spanish brought the coconut to the West Indies from one direction and Austronesian sailors from the other. Also called the “walnut of India” and “nux india”, the coconut gained its now familiar name from the Portuguese word for “head” or “skull”, eg: “coco”. The three dark depressions on the brown, skull-like shell do have the look of a face, don’t they?

The coconut fruit and coconut palm have been found to have many uses, both nutritional and otherwise. Most importantly, for the purposes of Emma and Jack, the maturing coconut is a convenient container that can hold ~300ml of nutrient-rich coconut water. And luckily for them, there just so happen to be a few coconut palms on their island.

Did They Have Enough?

In the plot of the story, Emma and Jack are going to find a more substantial water source after four days. They just need to survive until then. Now that they have the coconut palms, the next question is “Are there any ripe enough to hold liquid?” and immediately after that, “How many of those coconuts are there?”

Again, luck is with them. It turns out that the coconut tree ripens fruit all year round, with each ‘bunch’ taking up to 12 months to reach full maturity. It also turns out that each canoe-shaped pod of ripening fruit can contain a dozen or more coconuts.

A Coconut Tracker

With this information now in hand, I calculated the number of mature coconuts that would be needed for Emma and Jack not to die, at least until the plot moved far enough ahead that water was no longer the pressing issue.

In order to make sure that all was accounted for properly, I made a tracker where I ticked off so many coconuts each day. That way I was able to make the appropriate references in dialogue and description along the way.

And that’s what’s behind the line. (Or will be.) 🙂