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Comment by reactordev | Hacker News Reader

Ships are often balanced between providing power and consuming it. Excess power gen is wasted fuel. Excess power draw is a blackout so it’s very typical of a ships captain or owner to max out power consumption while minimizing power generation. Its a cost index.

I do this on my own sailboat with a solar power source and battery setup.

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Diesel generators simply use less fuel if there is less load than the maximum.

Not exactly. A diesel engine uses less fuel at 80% load than 50%. At maximum load it uses the most fuel but in general as load increases the engine gets more efficient and so the calculations are weird.

Note that generators need to run at constant rpm to provide the correct ac frequency. Your car has gears so that it can run at lower rpm at low loads and so you won't see the same effect.

An independent diesel generator could have been loaded onto the ship as easily as the spy equipment. It was a tanker, there was plenty of room for a genset and its own fuel. Then the ship's power plant wouldn't be taxed at all.

Then you have radio equipment in addition to an independent diesel generator and fuel to explain…

Yes it was a tanker. The bigger the ship doesn’t mean it has more people or more power generation like a cruise ship. A tanker has a crew of 4 plus captain, maybe?

You've got the spying equipment to explain if boarded. An extra generator is hardly a concern. If anything an auxiliary generator can be explained as a backup/replacement for the ship's mandated backup generator.

Generally the people ordering radios don't think about that. They are used to land where you have more power to the building than you could possibly use.

But it's not perfectly linear, and as should get bigger, the incentive to optimize grows

Less fuel less efficiently

There are many parts on a ship of that size which need power and are critical for safety. That is not comparable to leisure craft.

Thank you for your insight. Hard to believe nobody else thought of it before.

Whilst basic, its a critical and valid point. It is being made on a forum where shipping, ships, and related engineering issues are not well known (at all).

It does lead to questions about how backup and failover power work on large ships. Secondary generation? Central batteries? Per device battery failover?

Batteries, yes. And there's an emergency generator that runs on diesel (big ships run on "bunker oil") which can be started with batteries or manually.

https://www.youtube.com/shorts/_Y2VNS5TFFY (this one with a hydraulic hand pump)

https://marineengineeringonline.com/emergency-generator-on-s...

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