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Comment by aristophenes | Hacker News Reader

The problem with this is the diesel powered boat delivers, on average, 1,142 cars per day. The wind powered ship, being slower and with a slightly lower capacity, delivers 583 cars per day. Therefore, to deliver the same number of cars, you need two of the wind powered ships.

This extra 35,000 ton ship will be offset by saving 100 tons of CO2 per day (120 tons created by the diesel, minus ~20 tons created by the two sail ships). Is this worth it? How much CO2 does it take to build a 35,000 ton ship? And then of course the cost of a ship vs. diesel fuel.

Plus I presume the sail ships are now dependent on weather, which introduces logistical problems.

I suspect that coating the top of the diesel ship with solar panels and using the energy to supplement or replace the diesel engines might be a better use of resources?

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> Is this worth it?

Maybe it is, maybe it isn't. But if you keep replacing links of the supply chain with green alternatives, then it must eventually reach a point where you come out ahead. Eventually the energy for building ships will come from renewable sources.

Trying to tackle everything at once on the other hand may lead to paralysis.

I never thought about it like that before, makes sense. Thanks.

>diesel ship with solar panels and using the energy to supplement or replace the diesel engines might be a better use of resources?

Imagine having the sails be photovoltaic for them to become a dual-energy source themselves.

Plus you need more than two ships anyway, at least one for backup if not simultaneous return voyages.

Such a ship has probably an expected life of 40+ years so the CO2 savings of the wind ship vs the diesel one are at most (the ship won't be at sea continuously) about 1.5 million tons.

You make good points, and I don't know the answer, but a meaningful comparison should indeed be made over the ship's entire lifetime, from manufacture to disposal.

Just a thought experiment for the numbers on oil tankers. The big ones carry 2,000,000 barrels of oil, which translates to 860,000 tons of CO2 produced from their cargo.

As to fuel, the bunker fuel used by cargo vessels is really dirty.

https://en.wikipedia.org/wiki/Oil_tanker

https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca...

https://en.wikipedia.org/wiki/Fuel_oil#Bunker_fuel

There's probably a lot more to the calculation too. I can imagine the wind-powered vessel could have a longer operational lifetime and require less maintenance since there's no combustion. Then again, if the mechanism is fragile it might be the opposite. I think it's still valuable to put this into production and iterate on better and better designs as we learn. Even if this first try can't make the math work.

I my experience sailing, anything that moves will break fairly quickly, anything that doesn't move can break to. I imagine the forces involved are an order of magnitude higher than for a motor, simply b/c motors are comparatively small.

What if we do wind/solar hybrids?

While double the ships is more costly to procure, it’s more flexible and fault tolerant, so there are benefits!

Ultimately I think the question is, what is the price difference to transport a car, and if higher would customers pay more?

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