Unlocking the full potential of America’s Waterways
From water to land and back to water.
Ask anyone who has played the computer game civilisation, building your cities on rivers or the coast is a key tactical advantage. Moving goods, people via waterways was one of the very first examples of transportation technology after horseback riding. Things shifted back to the land with the advent of the wheel, roads, and automobiles, but as our cities and populations continue to grow and require ever increasing mobility throughput, we find ourselves at a stage where the next frontier of transport will be found back on the water.
Cars and trucks are great - but they need nice roads to work.
Road vehicles have transformed American society, economy and geography since their invention in 1920. They are nice and fast, they are smooth, quiet, all weather, and are reasonably energy efficient at 27 MPG for a light duty vehicle. They are also pretty cheap to run, at about 14 cents per mile paid for gas.
But there is a catch - to get those stats on a car, you need to drive it on a straight, smooth rigid surface that is going in the direction that you want to travel. In other words, a road. Roads are not cheap nor fast to build. Today in the US a new road costs somewhere around $5m per lane mile, and a new road project takes 2 to 3 years to complete.
The other downside of the popularity of the modern automobile is record road congestion in almost every major city in the US, not to mention difficulty parking the cars at both origin and destination. Adding more roads is pretty restricted due to all the land around existing roads being densely occupied by homes and businesses.
Why don't we currently use the water?
About 50% of US NFL cities have a major waterway running through them, with places like San Francisco, Seattle and NYC featuring the largest bodies of water. So why aren’t these waterways leveraged to provide transport options?
The short answer is that they are, as far as is feasible using existing marine technology, which is leaving a lot on the table. Take San Francisco as an example - one can take the SF bay ferry from the ferry building to Oakland in the East Bay in just 25 mins. But then you need to deal with the fact that there is a 2.5 hour gap in the middle of the day where there are no ferries. And good luck if you want to go to Berkeley, or the east end of Alameda, or Fisherman's Wharf, or Oracle park. The ferry is great at peak times when you can fill them up on the most major of routes, but anything more flexible than that is just not possible due to the existing physics of boats.
The challenge of boat physics
The core issue here is that with existing boat technology and how it relates to ride comfort and energy consumption. Conventional boats rely on buoyancy and planning forces to stop the boat from sinking. When this is the case, drag increases somewhere between velocity squared and velocity cubed, and it is also roughly proportional to the size of the hull which is quite large. Drag is also proportional to the density of the fluid, and water is a massive 800 times denser than air, so having anything at all in the water creates a massive amount of drag.
Where you are going slowly, like the raft or barge back in 5000BC, this isn't an issue, as the square of a very small number is also very small which means very low drag, and you can move around with a gentle breeze or a paddle. But once you start moving at a decent clip, v squared and v cubed get really big, really fast. With more drag to overcome, two things happen. The vehicle consumes a proportionally higher amount of energy, and the power output of the engine also needs to increase, which means a bigger engine, making the vessel heavier and sitting deeper in the water, and in turn resulting in more drag, creating a negative feedback loop.
Bigger is sometimes better
One solution to this is to make the boats bigger and longer. This takes advantage of the fact that bigger and longer boats have proportionally less drag for the same speeds than smaller boats due to less wave drag and less skin drag compared to the total displacement. This is why commercial cargo vessels and tankers are so massive, and continue to get bigger over time. But these improved economics only work if the vessel is full of cargo or passengers.
For a 400 passenger ferry like here in SF, when the ferry is full, the energy economics are not too bad - still worse than a car, but you avoid the traffic which is popular. When the ferry is empty the economics are plain terrible. You still burn 120 gallons of fuel per hour, even if there is just one passenger on board. If you were that one passenger (of which I have often been on my way home from work in Alameda) that ferry burned 60 gallons of fuel just for me to get home.
When they are that big you also need to build large ferry terminals to get everyone on and off. So more money, bureaucracy, and time.
Small is expensive and rough
For a car-sized boat (30ft long in boat terms) will use an astronomical amount of fuel to go anywhere. Mileage of 1MPG is considered good, for a modest 25 miles per hour on the water. That comes out to about $5 per mile, compared to the 14 cents per mile for a private vehicle. So you can see why no one is using small boats to get to work. The other major downside of a small boat is how rough the ride is at any speed above 10 mph. Hitting choppy water at 30mph in a boat is a rough time that is exhausting and nauseating. With small vessels however you can offer considerably more flexible routes and schedules, offering more point to point transit rather than hub and spoke systems.
So the roads are full, and we can’t build any more.
Boats use way too much fuel, or they are so big that you can’t always fill them up with people, and then they don't go where you want them to go.
Hydrofoil technology - the game changer.
Hydrofoils are a way to shift from boat-like drag numbers to car-like numbers. The solution to the boat drag problem is just get as much of the boat completely out of the water as possible, and eliminate 95% of the issue. This is done by using hydrofoil wings which are submerged under the water to create the lifting force needed to overcome the weight of the vessel instead of using buoyancy or hull planing forces.This is not an easy task as balancing an entire boat on wings and struts just a few feet of the surface of a moving surface of water, but more on that later.
The drag on the wing will still increase with the square of the velocity, but the area term and drag coefficients in the drag formula are an order of magnitude lower, and there is no longer any drag related to the production of surface waves. The upshot of this is for a medium sized boat, going at a medium to high speed, the drag is reduced by a factor of 5.
The second thing that hydrofoil technology can do is it allows for electrification. This is because without foiling a battery electric boat would be flat in a very short period of time due to the massive energy consumption. Electrification is beneficial because electric propulsion systems can be up to 90% efficient when it comes to turning stored electrical energy into useful mechanical work. An internal combustion engine can do at best ~30% converting chemical energy intro mechanical work, meaning that the electrical system if 3 times more efficient.
Hydrofoils can also be powered by traditional gas engines, albeit more complicated, as the engine and the propeller need to be connected by a drivetrain, greatly limiting the possible locations of the engine and creating flow-on challenges for weight distribution.
Combine the two, creating a hydrofoil boat powered by electricity, and now you have a combined 15x improvement in the overall energy efficiency compared to a regular boat. Back to the average car sized boat we mentioned earlier getting 1MPG and costing $5 per mile - convert it into an electric hydrofoil vessel, and depending on local electricity prices, and gasoline prices, you can get that energy cost of operating down to 33 cents per mile. There are a lot of simplifications in this calculator, and it’s intended to be illustrative. Many factors will influence this - the size and shape of the boat, it’s operating speed and weather conditions.
Once the energy or ‘gas’ cost of a vessel operating falls that low, it now blends with all the other costs like insurance, maintenance, depreciation.
The ingredients of a transportation revolution
Our thesis is that if you can improve a single dimension of a transportation technology by ~15% you will have a highly successful product. If you improve two or more dimensions by 100%, you create a transport revolution, as has happened before thought history. What are these critical dimensions of transportation technology?
Speed, comfort, range, convenience, cost, and emissions.
Some examples:
Railroads were 2x more comfortable than a horse and cart - (at least one can estimate from watching old time movies), and hence became so popular that the railroad companies formed the first ever monopolies in the United States.
Propeller planes like the DC-3 were 3x faster than the train, 5 times faster than cars and 4 times faster than ships. This created the first air transport revolution.
Jet planes were 3 times faster than propeller planes, and twice the range. This boom was the beginning of globalization.
A modern case study in a step forward in transportation technology
A modern analogy I like is the CFM-LEAP 1B turbofan. When installed on a narrowbody jet, it could improve the fuel efficiency by about 15%. It then spawned the creation of the entire new 737 MAX and A321 Neo aircraft designs so that airlines could capitalize on these savings. Two entire new lines of aircraft were created just because of a 15% efficiency improvement. That 15% improvement in efficiency netted CFM International around $160bn in orders for their new engine.
The incipient Hydrofoil revolution
Hydrofoil technology installed on a small to medium sized vessel can improve passenger comfort by about 3x removing motions from waves and swell, greatly reducing sea sickness. It can improve the energy efficiency by 15x, reducing the operating cost massively. They can reduce vehicle emissions to zero, which is a new and important dimension for vehicles. And did I mention that a hydrofoil is effectively silent?
Throw this together with largely empty waterways that are free to use, and it sounds like you have the makings of the next transportation revolution to me.
So, given that hydrofoil technology was first invented in 1869, why hasn’t there been a hydrofoil revolution yet? The reason is there has never before existed the right alignment of technology and market need like there is today.
The hydrofoil vessels that have been described require advanced computer stability systems to remain smooth and stable while in flight. While these systems have been possible from the 1960s, they can now be built using incredibly cheap off the shelf components combined with very clever software. The struts that hold the vessel up are long slender structural elements that can now be strong and light thanks to mainstream carbon composite technology. Off the shelf lithium ion batteries offer high performance and low cost, largely driven by advances and volume in the automotive industry.
The personal mobility market has transformed immensely in the last 20 years largely due to the advent of smartphones and ridesharing with the consumer expectation that they should be able to get point to point seamlessly on their own schedule. Emissions targets and mandates are coming into force in all developed nations with many bodies of water now banning gas powered boats.
The future is foiling
The waterways will be full of small and medium electric vessels moving people around. Recreational boating will be transformed with silent, smooth boats that leave no wake to disturb the shoreline. The military will insert their forces using silent hydrofoil vessels with no wave impact.
Valo will be the premier supplier of hydrofoil technology to the entire world, just like GE and CFM are for turbofan jet engines. A 15% improvement in efficiency in a turbofan engine landed 160bn in orders. Imagine that 15x efficiency could achieve with our hydrofoil technology.