Let’s Make Some Lightweight Solar Powered Boats!
- Laurence Clarkberg
- Jan 14
- 23 min read
by Laurence Clarkberg
I’m on a train with my wife Judy heading north from Miami to New York after having visited family in Puerto Rico. People always ask us why we choose to take the train instead of fly. Over and over again we have to explain that even though it adds a day to our travel each way we do it because trains emit less pollution than planes. We avoid flying because we value this planet we live on, and we don’t want to have to move to another one if humanity trashes this one.
And so the train is our first choice for long distance travel. However, it is not possible to take the train all the way to Puerto Rico due to a large body of water between Miami and San Juan. Judy and I tried to find an eco-friendly alternative to the plane but we are told that sailboats and ferries and other small boats cannot easily make the journey because of the strong currents of the Gulf Stream rounding Florida’s tip, and because of the persistent trade winds blowing from the northeast. “Rather than sail directly to Puerto Rico, it would be easier to sail to Europe first and then catch the trade winds back to Puerto Rico,” my sailing savvy brother tells me. We’re not gonna sail to Europe first. At least, not this year.
And so instead we have over the previous year carefully budgeted our long distance travel, declining other trips we might go on, so that we can make this 1,000 mile hop by plane from Miami to San Juan within our carbon budget. And the rest of the journey we do by train. That’s just who we are.
Arriving in San Juan we find that ground transportation on the island is challenging. The population is stuck in a vicious circle: because it is difficult to walk or bike or take public transportation, people choose to drive. And because people choose to drive, street space is limited: people park on the sidewalks. Cars crowd the narrow streets so tightly that parked cars have to tuck in their side mirrors. And people are so desperate to get through traffic that they drive very aggressively, making walking and biking life-threateningly difficult.
In spite of multiple lane highways throughout the city, there are constant traffic jams. On several occasions we have to abandon our plans to go somewhere because after we head out we are physically unable to get where we want to go because the traffic jams between here and there extend for miles. And several times even when we do get to our destination the parking situation is excruciatingly time-consuming and difficult.
And I think, this ground transportation situation is ridiculous and unnecessary. If half the people here rode ebikes instead of driving, they would get to where they were going much faster. The roads would be calmer and more spacious. Responsible parking would become possible. The air would be cleaner. The weather here is consistently great for biking even in winter. So what’s keeping people from doing the right thing? Very few people are confident enough to ride an ebike in traffic. And very few people are willing to be the weirdo, to do things differently. Not me. I resolve to bring an ebike the next time I visit Puerto Rico, and I contemplate even opening a solar-powered ebike business here.
And air-transportation to and from the island is no less challenging. A steady stream of jetliners roar overhead. In spite of this volume, the demand is even greater. When we get to the airport to leave we find a traffic jam encircling it. After heroically breaking through that barrier we enter a TSA line hundreds of people long. An hour and a half later we make it to our gate and find it is standing room only and our plane is delayed for two more hours. We have to step over people asleep on the floor from having spent the night in the terminal. We talk to a neighbor who says that they have been waiting at this airport gate for twelve hours and are not expecting to leave for another twelve.
There has got to be a better way, I think. On this train ride home I have lots of time to imagine what better transportation might look like. I imagine an amphibious vehicle, a bike that can tow a boat to the water, where the boat can then be unpacked and inflated to take the bike across the water. No lines to wait in, just an adventurous journey with my honey from anywhere to everywhere. But that’s just crazy, right? That’s just a caffeine dream from the cubano coffee I had this morning, right? And then I remember two people who actually traveled across Europe like this: they rode bikes towing boats across land and they rowed boats carrying bikes across water.
In 2006 National Geographic named Colin and Julie Angus “adventurers of the year” for their ambitious amphibious trip across Europe. In 2009 I went to see them on their speaking tour to promote their book “Rowed Trip” described here:
Some Personal History
I was greatly inspired by their talk, and a couple of years later I tried my hand at building my own amphibious bike which I called the Aqua Xtracycle. Little did I know where that would lead.
At that time the idea of a “cargo bike” was just being invented. Electric cargo bikes were not yet available; to get one you had to add a motor yourself from a kit. So I did that. The best option was to add a Stoke Monkey mid-drive motor to a Surly Big Dummy cargo bike. After adding the motor I went a step further and added pontoons and an electric trolling motor so that I could bike on the lake. I made a YouTube video of the Aqua Xtracycle that is still online here:
The bike worked well. The main problem was not the technology but that my first wife was not very supportive of my new hobby. She insisted that it was my parental duty to drive our kids everywhere like everyone else was doing. But I guess I’m just not like everyone else. I persisted with cargo biking. I relished getting groceries with it and taking my kids to school on it. I felt like here was a technology that could really change the world for the better for once. I got into cargo ebikes even to the point of starting a small shop to sell them.
I had a couple of visitors stop by my shop who really inspired me. One was a fellow ebike enthusiast from Syracuse named Troy Rank. One summer he read that the longest ebike trip recorded in the Guinness Book of World Records was less than 1,000 miles. “I can beat that!” he declared. Within a week he had loaded up his electric cargo bike with camping equipment and rode to Colorado and back, blogging about it along the way. I felt honored that he visited my shop on his way back home.
Another inspirational visitor was Dr. Sara Dykman, an entomologist who was returning from cycling alongside monarch butterflies on their 10,000-mile round-trip journey from Canada to Mexico and back. She writes about her epic journey in her book Bicycling with Butterflies.
I was inspired to make my own long distance journey by ebike. I made plans to bike the 500 miles from Ithaca New York to Washington D. C. I found that an ebike loaded with four batteries could easily do 100 miles a day. I had a great trip and I’ve since made that trip a couple more times. One thing I realized, though, is that it’s a drag when touring by ebike to have to find an outlet to recharge your batteries. To solve this problem I started putting solar panels on my experimental ebikes.
I got divorced in 2018. My first wife’s lack of interest in ebikes may have been a factor in our decision to get divorced. In 2022 I married Judy, a fellow ebike enthusiast. My marriage vows included agreeing to keep her own ebikes in good repair. One of the first things we did as a couple was to pioneer the sport of trainbiking: taking folding bikes on the train. We invented this sport when I realized that 80% of our friends and family lived within 50 miles of an Amtrak station. Trainbiking is a happy joining of two eco-friendly kinds of transportation that makes sense and really deserves to be promoted: rail travel for the long-distance parts of the trip and traveling by ebike for the short distances. That summer Judy and I got a month-long rail pass and traveled cross country to Burning Man and then to friends and family out west.
I had finally found an adventurous partner. After that trip Judy supported me in developing a series of increasingly capable solar powered tandem e-bikes that we have been testing together on multiple-day camping trips (see a short video here). Our collaboration culminated in riding a week-long 500-mile organized ride across Iowa last summer described here:
I have started bragging to friends that I’ve married “the last tent-camping wife.” I love her so much. Her supportive attitude has helped me blossom as an artist, inventor and adventurer. And now new adventures await for us and anyone else willing and able to bring solar and ebike technology onto the water. As Judy and I sit together on the train ride home I am reviewing the state of the art of solar powered boats on my phone. I have come up with five increasingly complex designs worthy of spending some time and money on bringing to fruition, which I will now share with you. I welcome your suggestions and help.
Review of Current Solar-Powered Boat Technology
I like being the first to make something new. I love the thrill of being at the cutting edge of new technology. I’ve had great success building some of the first solar powered tandem bikes and I realize that there are similar opportunities to create the first solar powered small boats. Here’s a sampling of what’s already been done in order from small to large boats.
Solar Kayaks
I like kayaks. I think of them as “the bicycles of the water”. As such they are the perfect boats to motorize with ebike-sized parts. This example from five years ago shows that just adding a 100 watt solar panel, a charge controller, a 12v lithium battery and a small trolling motor makes a very capable solar-powered boat:
I am most interested in a kayak catamaran design in which a steel tubing frame connects two kayaks and solar panels and an outboard motor are mounted on this frame. I found this example from seven years ago:
This is a great design. But in the last seven years solar and battery and electric propulsion technology have all improved, so it should be possible to improve on this design in many ways. I have more to say about this design later in this essay.
Solar Pontoon Boats
A next step up in size is to add solar panels to a pontoon boat. A pontoon boat is perhaps not the swiftest fish in the water, but it certainly has a lot of surface area on its roof to add solar panels. Here’s a great example made by a sort of a hippie commune in Wisconsin that likes to electrify old VW buses and tractors and outboard motors and such:
A solar pontoon boat makes so much sense that there are already a lot of commercial products out there. Here is one example:
Solar Yachts
Another step up in size brings us to solar-powered yachts which are likely to overtake the sailboat industry in coming years as the go-to boat for eco-conscious millionaires. Lots of commercial and DIY examples are out there. Here is a particularly well done example put together by a retired physics teacher who explains his setup in great detail. He has been careful to add some safety features such as putting a gap in his solar array to protect it from high winds, and adding lightning rods to protect his boat from lightning strikes. His boat features a 7kW solar array, a 32kWh battery bank, two 15kW electric motors and two diesel backup generators:
Even Bigger Solar Powered Boats
We are starting to see solar powered boats become possible on a commercial scale, for ferries and shipping and such. Check out this list of such boats on Wikipedia:
https://en.wikipedia.org/wiki/List_of_solar-powered_boats#:~:text=Alstersonne%20is%20a%2027%2Dmetre,In%20operation%20since%202022.
Three Kinds of Non-Combustion-Based Propulsion
As I sat on a beach in Puerto Rico last week I looked around me and I realized that the marine environment has at least three free energy sources to draw on to power a boat. There is the sun of course, spilling onto the surface of the earth to the tune of about a kilowatt per square meter. Current solar panels can capture at least 25% of that power and improvements keep coming.
Then there is the wind of course. The energy in one square meter of wind ranges from around 40W in a light breeze to over a kilowatt in 27 mph winds. Wind turbines could be placed on the deck of a boat to capture 20% to 40% of that wind power as electricity. Wind turbines can easily be added to solar powered boats because both systems can share a lot of the expensive electrical components, particularly battery banks and electric propulsion.
A solar boat can make use of wind energy for propulsion more directly than a wind turbine: it can carry a regular sail or a kite sail or a wing sail. (A wing sail is a new type of super efficient sail that looks like an airplane wing sticking up out of the deck of a boat.) One issue with a sail is that it can block the sun from solar panels on the deck. One way around this that we’re starting to see is to weave the solar panels into the cloth of the sail itself. Cool!
Also note that sea kayaks can be fitted with small triangular sales. The short masts can be flipped up when conditions are right and flipped back down again if the wind dies or if the wind gets too strong.
Using a kite sail to tow a boat is a nice way to supplement solar power because it won’t block the boat’s solar array, and also it can be stowed away when not in use. And the kite sail isn’t just for traveling downwind. Kite sails can go surprisingly close to the wind, often achieving angles of 45 degrees off true wind. I have a good friend who is into kite sailing so I’m excited to get his help trying out this technology with the boats I build. Here is an example of a commercial product, a kite sail designed to be added to the foredeck of a yacht:
The combination of wind and solar power is particularly nice for a boat. If conditions are stormy light levels are lower so solar power becomes limited, but at the same time the wind speed increases so wind power increases. And the wind can power a boat at night when solar panels are at rest.
The third energy source that I saw on the beach last week is not so obvious: the wave energy of the moving water itself. Waves can reach power densities of 60–70 kilowatts per meter of coastline in areas with deep waters.
Commercial grade stationary wave energy generators have been in use for decades now. But wave generators to power a boat are just now being developed. One notable example is a large ship named the Energy Observer sponsored by the Philippine government. It has a large central hull flanked by two outriggers. Waves make the outriggers move relative to the central hull and this motion pumps hydraulic fluid that powers a generator. Again, wave energy systems like this can easily be added to solar powered boats because both systems share a lot of the necessary electrical components:
Overall Design Considerations
My train ride continues. After reviewing the state of the art I start to think about what design choices I’ll need to make for my five solar boat designs.
Hull Design: Go Long!
In boat design there are two main types of hulls: displacement hulls and planing hulls (hydrofoils are a special case covered below). Displacement hulls have v-shaped cross sections and are intended to ride in the water and the water flows around them. Sailboats have displacement hulls. Planing hulls have flat bottoms and need to have lots of power to ride on top of the water. Fast powerful boats have planing hulls.
Since my boat designs favor distance over speed and will need to carry lots of weight and will need to use energy sparingly, they will all use displacement hulls. The main disadvantage to displacement hulls is that their speed is limited to a theoretical maximum by the flow of the water around them. What happens is that as the boat’s speed increases, a wave develops in front of the boat, and that wave holds back the boat. It is as if the boat is carrying around its own little hill that the boat has to climb over!
The only way to increase the maximum speed of a displacement hull is to make it longer. This creates the counter intuitive situation that longer boats are faster than shorter boats. For example a 27-foot racing shell that seats one rower is limited to a maximum speed of about 7 mph. But the 62-foot “8+,” with eight rowers and a coxswain can reach 10 mph. Theoretical displacement hull speed is calculated by the formula: velocity in knots = 1.35 x the square root of the waterline length in feet.
A happy coincidence is that when it comes to designing a solar boat hull, long is good: it means more area for solar panels. And unlike a solar bike which is limited by road size, a solar boat can take up a large area on the water. So we can go long!
What About Hydrofoils?
Electric boats that ride above the water on hydrofoils are a welcome recent development. And they are amazingly fast and efficient. See for example the Candela C-7, a 25-foot electric power boat made in Sweden that can go up to 34 mph:
However it remains to be seen if the small lightweight low-power boats that I have in mind are practical candidates for hydrofoiling. Can their solar panels generate enough energy to power a motor large enough to enable them to hydrofoil? The C-7 is able to do what it does because it weighs almost 3,000 pounds, carries a 40kWh battery, and is propelled by a 55kW motor. Powering that beast would require about 40 square meters of solar panels. I’m guessing putting that many solar panels on your C-7 would prevent it from being able to hydrofoil. My designs, by comparison, will weigh less than 200 pounds, carry 4kWh of batteries, and be propelled by one or two motors totaling 3kW. Such a setup can be reasonably powered by four square meters of solar panels. But is a 3kW motor powerful enough to get it to hydrofoil?
Perhaps instead of scaling down the Candela C-7 it would work better to scale up something like this Manta5 hydrofoiling ebike that draws 460 watts:
It would be possible to extend the range of such a vehicle by adding a 100 watt solar panel on top. However, for my first few solar powered boat projects I am going to postpone any effort to get them to hydrofoil, and instead focus on making them practical for long-distance touring.
All Different Kinds of Kayak Hulls
Hopefully I won’t have to make my own boat hull, and I can use a commercial product as a starting point. The most promising products are kayaks. Judy and I already have two 10-foot plastic kayaks behind our garage that I plan to use for our first project. What else is available?
There is a big difference between sea kayaks and recreational kayaks, as described well in this video:
Basically sea kayaks are longer, narrower, faster, and better suited for rough water conditions and for long-distance touring. Recreational kayaks (confusingly also called ocean kayaks) are fatter, more stable, and slower. They are better suited for short trips in sheltered waters.
Some recreational kayak hulls are designed for paddlers to ride on top of the hull and others are designed for paddlers to ride in the hull. People using a kayak for fishing tend to prefer the on-top kayaks for comfort while fishing, and people using a kayak for practical transportation tend to prefer the in-hull riding position. For my designs I want to minimize wind resistance and so I prefer in-hull kayaks if portability is not an issue.
Kayak hulls can be made from several different materials: wood, plastic, fiberglass or carbon fiber. And there are several kinds of specialty hulls made for ease of transportation: inflatable, foldable and modular hulls. I describe some of these below.
Using Solar-Powered Ebike Parts
As much as possible I want to use the same parts for the solar boats as I did for the solar tandem ebikes I’ve developed. In particular this means:
52v 20ah ebike batteries that weigh less than 10 pounds
lightweight flexible solar panels in the 100 to 200 watt range arranged in arrays of two to sixteen panels
small 10 amp adjustable charge controllers, one per 200 watt panel
small motors drawing between 500 watts to 2 kW of power
I avoid 12v or 24v systems because the wires required to get appreciable amps and therefore appreciable power are thick and expensive. And I avoid systems greater than 52v because connectors spark more at these higher voltages which can cause corrosion and melting. And the physics teacher who made the solar yacht described above points out that voltages higher than 52v are more dangerous because if you grab a live wire your muscles freeze up and you can’t let go.
Ebike motors are generally not immersible, and don’t have a good spot to attach a propellor, so I’ll need to find a good marine motor. For reasons that I don’t understand, the market has less-than-$200 electric trolling motors at one end and more-than-$2,000 outboard motors at the other end with no options in-between. I don’t like the trolling motors because they are usually 12v and often underpowered for my purposes. And I don’t like the more powerful outboard motors like the Torqueedo because they also use 12v batteries and the batteries are proprietary. Last year I found this Inexpensive Chinese 48v 1,200 watt “5hp” outboard that I am excited to try out:
I have also just ordered a new kind of motor built into a fin that can be attached to the bottom of a kayak or paddle board. It draws up to 400 watts of power from a waterproof battery and connects to a handheld steering control by bluetooth. Pretty impressive for $629!
One last design decision: when building solar-powered vehicles one has to decide whether to make the solar array tilting or fixed. A tilting array can be pointed at the sun to gather more power, whereas a fixed array is generally simpler and less likely to fail. With a solar ebike it doesn’t seem worthwhile to use a tilting array because the bike has to follow the road so you would need to constantly adjust the array when you should be paying attention to the road. You could create a tracking system but this adds complexity and another point of failure. And tilting isn’t that necessary when stopped. When you stop for lunch, you can orient the whole bike toward the sun and tilt it on its kickstand.
A boat on open water, however, is a different situation. It becomes possible to go for long stretches in the same direction, so a two-axis tilting array becomes much more desirable. If possible the array could also have a way to be raised and lowered. In high winds it can be lowered close to the water to lower wind resistance, but in a calm situations it can be raised to provide shade.
I can quickly and easily create a prototype steel frame for a solar array using Makerpipe fittings with inexpensive EMT. If I like the design, I can weld up a more robust frame out of lightweight strong cromoly tubing.
Design 1: The Sunyak, a 10-Foot Recreational Catamaran
For my first project I plan to create a steel frame that connects two 10-foot kayaks. I’ll mount solar panels and an electric outboard motor to the frame. I am calling this contraption the Sunyak. My design goals are as follows:
Able to carry two passengers up to 5mph.
Has a range of 50 miles.
Able to fit into a 14’ x 6’ x 6’ cargo trailer.
Light enough for two people to lift, so less than 100 pounds.
Able to carry 50 pounds of cargo such as food and overnight camping equipment.
Designed for sheltered waters on calm days.
Able to deploy a small sail if wind conditions are good.
To achieve these design goals I plan to use the following parts:
We have a couple of old ten-foot kayaks I can use for the prototype. However, with the weight of the solar array and batteries and motor they may ride too low in the water, in which case I can switch them out for two 12’ kayaks.
I can probably use a solar array twice as large as the Honey Cycle uses, so four 2.5’ x 5’ 200 watt panels for a total of 800 watts.
The inexpensive Chinese outboard motor I have claims to be able to handle 1,200 watts so that should work well with this design.
This design can carry a bank of four 52v 20ah batteries, each connected to a 10 amp charge controller connected to a solar panel. I can connect the four batteries to the motor with three battery doublers. Four batteries this size will have about 4 kWh of energy. This much energy would give an ebike a range of 100 miles, but I suspect the boat’s range will be less. Can it go 50 miles?
I may want some sort of waterproof enclosure for the batteries, such as a Pelican-style case.
Design 2: The Suncat, a 14-Foot Bikerafting Catamaran
Bikerafting is a recent adventure sport in which an adventurer carries an inflatable raft on a bike to a body of water, and then inflates the raft and carries the bike on the raft. Here’s a short video on what most people mean when they say “bikerafting”:
What I intend to build is a catamaran that uses two inflatable kayaks with a frame between them to mount the solar panels and to carry two ebikes in an upright position. I call this design the Suncat. The parts of the frame can be reconfigured in the field to make two bike trailers that can carry the deflated kayaks. Let’s see if this is possible! This vehicle would have the same design goals as the Sunyak but with additional constraints. For such a vehicle weight and portability becomes super important. There are now kayaks available that weight less than 35 pounds and can be deflated to fit into a backpack. One possible kayak to use for this vehicle is this 14’ model. It is possible to add fin motors to this kayak:
However, a good design challenge is making use of the same parts for both the ebike and the eboat. Would it be possible to mount the ebikes in such a way that they can be operational in boat mode, but driving a propellor instead of a rear wheel? So for example the ebikes’ BBSHD mid-drive motor could be used to crank a kayak pedal drive like this one:
Design 3: The Caryak, a 14-Foot Amphibious Bicycle
Another wild possibility would be to attach three or four bicycle wheels with hub motors to the sides of an electric pedal-powered kayak. I call this design the Caryak. When driven on land, the power would go to the hub motors. When driven on water, the wheels could be detached or lifted out of the way and the power would go to the props on the bottom. Here is a good possible kayak to try out this design, though the 36v battery seems underwhelming to me:
There is also a 13.5’ x 36” tandem version of the Old town Malibu Pedal T available. To make the first ever electric pedal tandem kayak would require getting this $4,000 kayak:
and outfitting it with two of these $2,500 pedal assist retrofits:
Adding a solar array and possibly even wheels to this tandem kayak would be an interesting design challenge.
Design 4: The Solar Hopper, a 22-Foot Island-Hopping Day Cruiser
After gaining some experience with the previous two solar boat builds, I have in mind to create a longer solar-powered catamaran with a range of hundreds of miles over open waters. I call this one the Sun Hopper. I imagine it could be used for island-hopping expeditions in the Caribbean or even the Aleutians as described in this video about two women who paddled sea kayaks on a 100-day 1,500 mile island-hopping journey along the Aleutians:
For such island hopping it would have to be light enough and have a shallow enough draft that it could be beached easily.
It might be worthwhile to build a custom hull for this one, but if that proves too daunting the 22’ Northwest Seascape 3 sea kayak looks like a good choice to use as a starting point:
It would be fun to try out this kayak before buying by joining one of these expeditions:
Another possible starting point would be to obtain two “8+” rowing shells that normally carry eight rowers and a coxswain. These narrow lightweight hulls are 62’ long, so the maximum displacement hull speed would increase to 12 mph. However transporting such a long boat would be challenging. Used 8+ boats can be had for as low as $5,000 each here:
At 22’ long the Solar Hopper would be twice the size of the Sunyak and so the design goals would be more like this:
Able to carry up to four passengers at up to 7.3mph.
Has a range of 200 miles.
Able to fit on a 20’ boat trailer.
Light enough for four people to lift, so less than 200 pounds.
Able to carry 100 pounds of cargo such as food and overnight camping equipment. And it could carry several hundred pounds more if it was only carrying two passengers.
Able to withstand stormy conditions.
Able to deploy a wing sail if wind conditions are good.
To achieve these design goals I plan to use the following parts:
Two 22’ Northwest Seascape 3 sea kayaks.
Eight 2.5’ x 5’ 200 watt panels for a total of 1,600 watts.
Two 48v 1,200 watt inexpensive Chinese outboard motors.
Eight 52v 20ah batteries, each connected to a 10 amp charge controller connected to one solar panel. I can connect two sets of four batteries to the two motors with six battery doublers. Eight batteries this size will have about 8 kWh of energy. And I can carry as many more batteries as necessary to bring the range to 200 miles.
Waterproof enclosures for the batteries.
This boat wouldn’t have sleeping accommodations but it might be worthwhile to have small cooking facilities onboard.
The kayaks could be fitted with small sails.
I’d want to use a hand-held gps.
Design 5: The Solar Crosser, a 40-Foot Ocean-Crossing Catamaran
This is highly speculative at this point, but it should be possible to build a lightweight solar-powered boat capable of crossing the Atlantic. Heck, there are people who have kayaked across the Atlantic, including 65-year-old Aleksander Doba. He designed a 23’ sea kayak that has a self-righting buoyancy arch if the boat capsizes in rough waters. He traveled at an average speed of 1.4mph and made the 3,352-mile crossing in 99 days:
And then in subsequent years he crossed the Atlantic two more times.
A 40’ solar-powered boat would have a maximum displacement hull speed of almost 10mph, so it should be able to make the same journey in two weeks. As a first pass thinking about how such a boat might come together, my inclination is to make a catamaran out of two 40-foot-long 48” diameter steel tubes. An enclosed cabin could be mounted between the tubes in a low bubble. Solar arrays would be placed before and after the cabin. The ends of the hull could have buoyancy arches like Doba’s boat. Such a boat could be transported on a standard tractor trailer truck which is 8.5 feet wide and 53 feet long. This boat would be twice as large as the previous design, the Solar Hopper, and so the design goals would be more like this:
Able to carry up to eight passengers at up to 9.8mph.
Has an unlimited range.
Able to fit on a standard tractor trailer truck.
Weighs 500 pounds.
Able to carry 1,000 pounds of amenities and cargo with two passengers on board.
Able to withstand stormy conditions, perhaps incorporating a buoyancy arch and other self-righting technology.
Able to deploy a wing sail if wind conditions are good.
To achieve these design goals I plan to use the following parts:
Hull made from two 40’ x 48” diameter steel tubes.
Sixteen 2.5’ x 5’ 200 watt panels for a total of 3,200 watts.
Two 10kW inboard electric motors.
Sixteen 52v 20ah batteries, each connected to a 10 amp charge controller connected to one solar panel. I can connect two sets of four batteries to the two motors with six battery doublers. Sixteen batteries this size will have about 16 kWh of energy. And I can carry as many more batteries as necessary to increase the range.
Waterproof enclosures for the batteries.
This boat would have sleeping accommodations, a head of some kind and small cooking facilities onboard.
This boat could make use of a wind turbine and small sails or a wing sail to increase its range.
I’d want to have a gps map console in the cabin.
Thinking Even Bigger: A Shipping Container Boatrain
Lastly I conceived of an intriguing design that I don’t plan on building myself but I’ll put it out there for any entrepreneurs who want to run with it: it should be possible to make the Solar Crosser large enough to carry a 40’ shipping container, and to make it autonomous like a drone. Solar panels could be placed on top of the shipping container to power it. A line of such modular boats could then be connected together into a kind of a “boatrain” for traversing the ocean efficiently together. Perhaps the joints between the modules can generate electricity from wave energy. After crossing the modules could break apart and travel individually to separate destination ports. This avoids the expense of unloading and trucking the shipping containers from a central large port.
Action Items
Where do we go from here? I plan to get started on the Sunyak as soon as it gets warm enough to work outside. I have to clean out the kayaks behind the garage because a rabbit dug a hole under one of them, and threw all the dirt he excavated into the kayak.
Who wants to join me? It would be fun to make several experimental solar powered boats and to race them across the lake. Cayuga Lake is between 1 to 3.5 miles wide so that would be a good place to start. And Cayuga Lake is 40 miles long so that would be a good test of the Sun Hopper. Next would be trying to travel from Miami to San Juan and back. And lastly on the solar boat bucket list is to try an Atlantic crossing.
The clackey-clack and gentle rocking of the train slowly lulls me to sleep. As I drift off I begin to wonder, how hard would it be to make a train car powered by solar panels? A train uses about 6kW of power per passenger to go up to 80mph. But if we made the top speed much lower than that, say 30mph, and made the train car much lighter, we could probably get that power requirement figure down to 60W per passenger...
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