101–110 of 233 posts
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"Fan" implies the propulsion is in response to air being forced backwards. These rotors create lift in a forwards direction from the wind blowing across them, a bit like having a fixed wing pointing up.
But you want to make sure you aren't just creating drag you have to fight against. So even with the rotors, the wind direction still matters.
Wonder why ships aren't trying solar panels and electric motors and auto-pilot... they're out in clear Sun, have a large surface area, and no traffic...
Some years ago I read The Box by Marc Levinson, a history of containerized shipping. Highly recommend it. If you live in SF and have wondered about the numerous barely used piers, this book explains their history as well - and why the major container terminal ended up in Oakland instead. One of the painful early lessons for the industry was the discovery that minimizing operational costs (particularly fuel and mainte…
Ignorant question: if operational costs trump all, especially fuel (Maersk says in the article 60% of operational cost) why not pure sail power? Is there some other maintenance cost or infeasability there? Or is there another hidden variable that is not satisfied?
I picture a small-ish shipping ship, say something moving 20 or 30 containers only, fully autonomous (100% crewless) with sails and solar only powering it. Solar electric motors handling the near-land operations and "not enough wind" conditions, sails otherwise. If you had autonomous loading and unloading, you would have zero variable/operational cost.
I am certain there are very good reasons this would never work, but I still love the idea.
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How big is the check and why? That's what's so hard to get an answer for when people are determined already to not to try. I mean, I guess I have Google and a long-weekend. I was hoping for someone to drop an URL that can explain this and provide key terms.
Throw out a speculative idea, get a speculative answer. Dunno why you’re expecting me to go all civil engineer on you, nor do I understand why you’re acting like I’m the barrier to the idea being tried. Go do the math yourself, it’s your idea.
Some years ago I read The Box by Marc Levinson, a history of containerized shipping. Highly recommend it. If you live in SF and have wondered about the numerous barely used piers, this book explains their history as well - and why the major container terminal ended up in Oakland instead. One of the painful early lessons for the industry was the discovery that minimizing operational costs (particularly fuel and mainte…
Ignorant question: if operational costs trump all, especially fuel (Maersk says in the article 60% of operational cost) why not pure sail power? Is there some other maintenance cost or infeasability there? Or is there another hidden variable that is not satisfied?
So you can use sails to help, but if you rely on them you might be late.
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> Salt water destroys everything This is the statement I hear relating to all kinds of ocean-based renewable energy ideas. Sources are never provided. The problem must have to do with economic viability and the replacement/maintenance costs exceeding savings. Could you supply sources to elaborate on where the break even point of solar tail (or any two other ocean renewable energy) systems would be as relates to costs…
I don't have a source, but as an engineer working for the US Navy, we are frequently told that the Navy spends an enormous amount of money on corrosion control. Like, in the billions to tens of billions of dollars per year. As a consequence, corrosion control is a significant fraction of the Navy's R&D budget. https://www.gao.gov/assets/650/647926.txt https://www.onr.navy.mil/en/Science-Technology/Departments/C...
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How big is the check and why? That's what's so hard to get an answer for when people are determined already to not to try. I mean, I guess I have Google and a long-weekend. I was hoping for someone to drop an URL that can explain this and provide key terms.
Throw out a speculative idea, get a speculative answer. Dunno why you’re expecting me to go all civil engineer on you, nor do I understand why you’re acting like I’m the barrier to the idea being tried. Go do the math yourself, it’s your idea.
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Hydrogen fuel cells are looking likely. Solar will probably produce too much electricity for usage during the day, so use that spare energy to split water to create Hydrogen fuel.
I was curious how much sense this actually made so I did the math, sources at the bottom. I suspect my sources aren't perfect, but they're probably close enough to get an idea of things. Our hypothetical container ship is roughly 400m x 59m, or 23600 m^2, and solar panels generate ~4.5 kWh/m^2 after inefficiencies, giving a total energy generated of 106.2 megawatt hours per day for a ship, if you had a big solar arra…
Obviously at this point fuel cells cannot produce the power output that diesel engines can at a given weight. But your power estimates on what a hydrogen fuel cell can do are off by a bit. Some quick searching finds portable 1MW fuel cells, existing 11MW power plants, and a planned 80MW power plant that's being constructed soon in South Korea. Obviously the latter probably weight too much for a ship today, but as the weight comes down that becomes a possibility.
Wonder why ships aren't trying solar panels and electric motors and auto-pilot... they're out in clear Sun, have a large surface area, and no traffic...
https://www.km.kongsberg.com/ks/web/nokbg0240.nsf/AllWeb/4B8...
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I was curious how much sense this actually made so I did the math, sources at the bottom. I suspect my sources aren't perfect, but they're probably close enough to get an idea of things. Our hypothetical container ship is roughly 400m x 59m, or 23600 m^2, and solar panels generate ~4.5 kWh/m^2 after inefficiencies, giving a total energy generated of 106.2 megawatt hours per day for a ship, if you had a big solar arra…
Clarification: I was talking about using excess electricity from shore based solar units. This would give operators somewhere to dump excess power cheaply (preventing negative electricity rates), all while providing fuel that's easy to store and usable in applications where batteries wouldn't work. Obviously at this point fuel cells cannot produce the power output that diesel engines can at a given weight. But your p…
My estimate didn't assume the ship left the shore with any hydrogen fuel. I (apparently incorrectly) assumed you meant that the ship would generate its own hydrogen during the day from excess solar while it was in transport.