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@cybergibbons | |||||
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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 :)
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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Wow, big difference!
But, it gets worse.
Those reefer positions all need power.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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!
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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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.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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So I think at best... we have 750 * 120k = 90 Mega Bananas.
Enough for everyone in the UK and me.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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This is what happens when you just multiply containers by how much you think is in them.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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5. sij |
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For those of you interested in what the engine room of a container ship looks like, I posted some pictures last year:
twitter.com/cybergibbons/s…
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[asa]
@a_s_arthur
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4. sij |
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Bananas don't tessellate and there's a maximum number of bananas you can stack before they crush the lower ones, meaning you also need space for strong enough packaging to stack. Have you accounted for this?
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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4. sij |
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The boxes have reinforced corners for pallet stacking. pic.twitter.com/0QnBN0Vt72
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Radu Caprescu
@verrigo
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5. sij |
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I just have to say, as far as intersections go, your intersection of bananas and cointainer ship knowledge is the most unexpected and awesome
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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5. sij |
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I'd actually imagine most 4th engineers on container ships would know most of this - keeping the refrigerated cargo in good nick is your job!
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Eric Ericson
@egericson
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4. sij |
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Wait, banana specific ships?
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Ken Munro
@TheKenMunroShow
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4. sij |
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Well, there are car-specific ships. And I REALLY like banasao
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Darren Robinson
@motorbandit12
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6. sij |
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What you do is seal the hatches, evacuate the holds and flood with nitrogen. Clean, non-toxic and prevents rot and ripening. At least they did on the ships my Dad worked on as Chief Engineer. Just don't fall asleep in the hold if you're a stevedore on a break.
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Cybergibbons! (Project Zero Hounslow)
@cybergibbons
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6. sij |
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Interesting how containerisation has made things worse in some respects maybe?
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