Cybergibbons

First up, how many bananas in a container? A standard forty footer holds 20 pallets. There are maybe 6 boxes of bananas per level, 10 levels, and 100 bananas per box? 120k bananas per box.

So that's more, right? 120k * 15k = 1.8 GigaBananas? Nope.

15,000 containers will be referring to TEUs - twenty foot equivalent units. 120k * 7.5k = 900 MegaBananas? Nope.

Is it weight? A banana weighs about 125g. So, around 15tonnes per forty footer. That's far short of the maximum of 28 tonnes.

So what is it? It's power.

Even the biggest container ships - for example, the Emma Maersk with around 11k fully laden TEUs - only have 1k reefer sockets onboard. Assume those are all filled with forty footers. We are down to around 1k * 120k = 120 MegaBananas.

Wow, big difference! But, it gets worse. Those reefer positions all need power.

We used to factor around 4kW for a reefer... so that would be around 4MW total. Easy! Problem is, bananas are not average. Most frozen cargo is taken onboard frozen. It doesn't take much power to keep it frozen at -21degC

Bananas are different though - they are often packed warm, and brought directly to the ship. They are also kept at +14degC. This means the refrigeration needs to work harder.

We are now looking at as much as 20kW to cool that container when it comes onboard, and 8kW to maintain the temperature. We've jumped to 8MW at least! That's changed what you are doing in the engine room.

Each of the 5 generators on the Emma Maersk is around 4MW. You are now running 3 generators just to keep the ship running in port!

Worse still, the shaft generator (the thing that recovers power from the main engine) is only 8.5MW. You are now having to run extra generators. Not economical. But doable.

So where does all that heat go from the refrigerated containers? The air. That's fine above the hatches. But what about below the hatches? Well, you need fans. And a lot of them.

No container ship I worked on had enough below hatch ventilation to handle 100% bananas. 100 containers dumping 8kW of power under a hatch is a lot. Total guess, but I don't think you'd manage more than 75% of reefer being at full load.

So I think at best... we have 750 * 120k = 90 Mega Bananas. Enough for everyone in the UK and me.

How do shipping companies handle this? Well, there are actually special banana ships - they are open hatch and can easily handle the load. Anyway, hope that was fun :)

This is what happens when you just multiply containers by how much you think is in them.