O. Ships

O1. Kitesurfing towboats pull existing cargo ships across oceans

Is a kitesurfing robot an impossibility? Well, nobody has ever built one, probably because nobody has ever tried. Is that anyone's proof of impossibility?

The world's fastest kitesurfer has reached 116 kph (72 mph). I recommend prototyping a supersized kitesurfing towboat that can tow an existing cargo ship across the ocean with wind power.

Kitesurfers regularly tack into the wind just as sailboats do. With such tacking abilities, perhaps 90% of every ocean-going ship's fuel use can be displaced by the pulling power of a kitesurfing towboat. At times, cargo ships may tack or zigzag across the ocean in order to displace fuel. Existing ships can be retrofitted with strong towing points on their hulls. Near a port, an ocean-crossing towboat can release its cargo ship to a local pilot, have a port call for the crew and then grab the next ship out.

Kitesurfer boards have hydrofoil surfaces beneath the part of the board that the surfer stands upon. In the picture above the main part of the kitesurfer's board is up above the water's surface and a thin post leads down to the underwater hydrofoil part of the board. Balancing an entire towboat on a hydrofoil may not be an overwhelming engineering problem because we live in an age where the Segway Scooter is old hat. I'd expect a rather huge sail area and a hydrofoil on the towboat with a rather huge cross section. In addition the tug will need the ability to retrieve the kite sail in bad storms. As with most prototypes, drawing the towboat comes first, then a microsized version is sculpted...

As I teach with two kite wind power sails, I favor a lighter-than-air kite sail design and in using high altitudes for steadier power.

Maritime shipping accounts for 3% of total greenhouse gas emissions.

8/17/26 In an optimized economy, a kitesurfing tugboat could pull a ship eastbound across perhaps 90% of the Pacific Ocean, then disengage that ship to let the ship motor into port and unload. Then it could quickly attach itself to a westbound ship and pull that ship westbound across 90% of the Pacific Ocean, then catch yet another eastbound ship, then a westbound ship, then finally head for port for the crew's downtime and for any ship maintenance. In this way the tugboat could optimize its value to the shipping industry. As with commercial jetliners now, the wind-powered towboat would follow weather forecasts to make the best times versus the lowest fossil fuel expenditures. At times a mixture of fossil fuel power and wind power will be optimal, but at least some fuel will be displaced. In case of unacceptable weather or waves, the towboat disengages and the cargo ship plows through the gale alone.

For further reading: Putting a kite on a ship for power: https://www.airseas.com/ Simply putting a kitesail on an existing ship can only displace perhaps 10% of the ship's fuel use. Unfortunately, existing cargo ships would need far larger and stronger keels in order to better utilize wind power. Also, the lateral pressures of kitesailing will tend to roll the ship over, and heeling over could be an unsafe complication for almost any existing cargo ship.That's why I recommend new kitesurfing towboats for pulling older ships straight forward by the bow.

O2. Mandating port to port cargo ship speed limits

Friction is related to a boat's velocity through the water, raised to the third power. (I've elsewhere seen "raised to the fourth power," same conclusions here). By putting transnational speed limits on ship speeds relative to the need to avoid certain dangers, we can greatly cut worldwide fuel use. Any port in any individual nation can announce tomorrow that they won't offload a certain ship, allow pilot service or allow a port call before a certain ship's expected day and time of arrival. The captain will then slow down to best conserve the ship's fuel. Trucking companies already use GPS to monitor the top highway speeds of their fleets of trucks.

It's possible to monitor almost every ship's progress across the ocean. By checking the ship's progress 75% of the way across the ocean, 95% of the way and 100% of the way we can tell if the ship is speeding and dock the carrier (wild guess, $1 per minute that the ship is early at each checkpoint, times the ship's gross tonnage). This gives the ship's captain latitude to minimize fuel use and equally to steer around any storms. The captain will almost always choose to slog along at an optimum fuel-saving pace over the distances between checkpoints. Other incentives such as prohibiting early loading-unloading at the destination port might also encourage better fuel use.

O3. Reticulated ships

8/15/26 We already have reticulated buses on the road. Why not have passenger ships with joints that can travel more easily up rivers? Each joint would come equipped with its own propellers. It's possible for each section of such a boat tohave one joint section at most, and the sections detach so that one section of the boat at a time can make it through a series of locks. A reticulated boat may or may not save energy but I wanted to add it for completeness. At least a single very long boat decreases total water friction on the boat for the same load, and a bendy boat can go around the curves in a river with minimal total water friction..

The universal joints where reticulated ships bend will most probably be spring-loaded plus they will carry shock absorbers in the up-down direction and also in the left-right direction, to handle powerful wave action.