We've all seen articles about massive container ships of the future using kites to supplement their engines, but I suspect a really solarpunk future would look a bit further afield, or perhaps further back in time for their ship designs.
I think in any future with humans and continents, people are going to be trying to cross the ocean. There might be less shipping in a world without our abundance of cheap energy, or more of a focus on reducing consumption and producing necessities locally, but people will still trade goods and travel. So what might the ships look like? Return to tallships? Solar panels and electric motors? I love reexamining traditional technologies to see how they can fit with modern engineering and design principles, safety features, and electronics, but I don't know much about ships, and especially not much about modern sailing.
So what do you think will be bringing back holds full of old world fashions harvested from the Chilaen desert?
While container ships will win for bulk shipping (discussed in a different comment), I wouldn't be surprised by the use of airships.
A large, modern airship wouldn't have the problem of the Hindenburg etc. We can make lightweight materials that can stand a brief hydrogen fire. Further, modern solar panels can be thin light and flexible. If you covered the skin of an airship, you would have significant generation capacity, particularly when above the clouds (solar works better in the cold). Excess power can generate hydrogen for both lift and fuel. This just needs water, which also makes an excellent ballast.
While it would lack the speed of a jet, it would have more capacity, and lower fuel requirements. While it would lack the sheer capacity of a container ship. it would be a lot faster. It would also be able to go across land, and so access more areas, and cut long detours.
Add rail to this mix, and you have most bulk cargo requirements covered. Jets and trucks can fill ultra fast, and last mile delivery niches respectively.
I'm really digging the modern reconsideration of airships. Between the more advanced materials, the higher-tech drive, control, and navigation systems, and the advantages in low-input operation and ability to park anywhere, it seems practical. I like that it seems like a pretty closed system once built, aside from maintenance. I didn't ask this question specifically for art ideas, but I'd like to do a photobash of airships in use at some point.
Do you have any idea what modern airship yards would look like? I dig the look of historic mooring towers and airship sheds but they're probably not as practical - from reading wikipedia it sounds like some modern ones can just land on the ground, which is less stylish but probably way easier for everyone involved. And it sounds like the canceled CargoLifter ones were supposed to operate something like a flying crane and winch cargo up from the ground.
I don't know how much you know about them, but if you (or anyone) have any airship designs you really like, I'd love to see them. The top covered in solar panels is a cool look, concept art I've seen has the airships in all shapes and configurations which I don't know enough to differentiate reasonable designs from bad yet.
First a proviso, while I've a better physics education then most, it's FAR from focused on this area. Take my ideas as the ramblings of an educated layman.
Shape wise, it will likely be best a cross between a bullet and a wing. You want it to present a blade-like cross section to the front for cutting through the air, with a trailing tail to reduce drag turbulence. You also want to limit the side cross section to limit wind sheer effects, though this is less critical. The end result is an inflated flying wing shape. This also gives a large area on the top for solar panels.
The airship will also need propulsion. 3 ideas spring to mind. Ducted fans would potentially work well for forward thrust. (Think finger jet engine arrangement). For maneuvering, you'll want pods of some description. Vector thrust options mirrored around the centerline. These could be ducted pods, like those used to maneuver cargo ships, or more quadcopter like, with larger exposed fans. Aerodynamics will be a big limit however. They will either need to be part of the main thrust generation, in flight, or fold out of the air stream.
As for a depot etc, I suspect it will be closer to a ship unloading dock. The main docks will have the airship latched down to the ground, for efficient loading and unloading. Outside that, they will likely want to tether. This lets them turn into the wind. Think something like this: Random image I found Not the prettiest site, but practical. Enough room to avoid collisions, but otherwise anchored. Airships would require some sort of mooring pole, so it would likely be more regular in arrangement.
This is awesome, thank you!