I’ve been working on an oceangoing ASV for years as a side project to demonstrate some of the marine robotics components we make at Blue Trail Engineering. I finally got it done and launched it on February 8, 2025 from Avila Beach, California. The original destination was Hawaii, but the boat outperformed expectations and ended up making it all the way across the Pacific. The total distance traveled was 13,322 km, which I believe is a record for a solar-powered autonomous boat.
Special thanks to Blue Robotics’ own @tony-white for taking the time to go out and meet the boat as it passed Hawaii! He’s the one who snapped this picture.
This boat used a Blue Trail Engineering thruster (the MTR-2000), rudder servo (SER-2020), and cables and connectors (our Cobalt Series), with Blue Robotics batteries. The autopilot was an Arduino running homemade code (and by “homemade,” I mean that I copied it from various places on the internet). The code left a little to be desired, especially in the area of power management, but all the mechanical and electrical bits worked flawlessly during the 4-month voyage.
While passing close to land on June 5, the boat was taken out of the water by an Indonesian fisherman. A local tour guide helped us track down the boat and got some pictures of it. The propeller had been chewed up pretty badly and one corner of the solar panel deck was bent (which indicates a pretty hard hit by something large). Interestingly, there was very little fouling on hull.
I had grand plans of writing a build blog for this project but never did. If anybody has interest in the details of how it was built, let me know. There are more photos of the boat here, and the basic specifications are as follows:
Length: 2.6 m
Mass: 28 kg
Solar panel: Sunbeam 126 Tough++ (it didn’t actually generate 126 watts, though… closer to 100 watts)
Solar charge controller: Genasun GV-10
Motor: Blue Trail Engineering MTR-2000
Motor controller: Castle Creations Phoenix Edge 50
Propeller: APC Sport 8x8
Batteries: 2x Blue Robotics 14.8 V, 18 Ah (total of 532 watt-hours)
Battery protection: BatterySpace #6221
Communication: Rockblock 9603 satellite modem
Autopilot: Arduino ESP32 running homemade code
Battery and motor control/measurement: Arduino ESP32 running homemade code
Other electronics: Pololu MinIMU-9 v6 for attitude and heading, Adafruit Mini GPS PA1010D for position, EagleTree RPM Sensor for motor RPM, multiple INA260 for voltage/current measurements, R/C receiver for manual control
Hull construction: wet fiberglass layup co-cured with expanding polyurethane foam, G-10 reinforcements in key locations
Solar panel base construction: 1/2" foam core laminated with carbon fiber
Rudder construction: carbon fiber
Keel construction: aluminum spine overmolded with urethane, 4.5 kg of lead in keel bulb
Yes, it really was an airplane propeller, spinning at roughly 500 RPM. Airplane-style propellers are generally more efficient for low-speed, low-power applications. Next time I’d like to get one made out of metal instead of plastic for increased durability, but I’m not sure how pricey that will be.
Congratulations! I remember following your first attempt and how cool and novel it was to have a personally owned USV just out there cruising the ocean. Thanks for listing off your BoM and nice finds with the charge controller (actual model: GV-10-Li-16.7V-RETAIL?) and the PCM. Balancing off solar was always a concern and some of these Li-ion chargers didn’t exist years ago.
Aside from all your other accomplishments, another amazing thing is the lack of marine fouling in the picture from Hawaii. For a hull that has been in tropical water, it’s remarkable.
Thankyou! And yes, you’re right about the Genasun part number.
On my first attempt, there actually wasn’t an MPPT at all; I had a protection circuit to keep the battery from overcharging but there was no device to match the solar output to the battery input for max power. An electrical engineer friend of mine told me I probably wouldn’t need it with the particular battery that I was using (5-cell LiFePo4) because the optimum voltage for the solar panel was so close to the battery voltage.
Hi @psupine , yes, it was remarkable how little fouling there was. But it’s possible that the fisherman who took it out of the water cleaned it off. Not sure.
The average speed was about 1.5 m/s for most of the voyage.
Thanks, @rjehangir! This boat was about five years in the making, so obviously I was a little distracted by the business!
Sometimes I called the boat “Nomad” (which is my name spelled backwards) but I never really liked that name. So really it’s just “the boat.” Sometimes engineers have trouble with creativity, you know.
Do you think you will put together a build blog like you did for your SeaCharger? We learned a ton from that blog a few years ago.
We are very curious how you were able to achieve an overall average speed of +3 MPH with only 532 Wh of battery? What is the power consumption for your MTR-2000 at 500 RPMs? As well, what is your hotel load?
Thanks again for all the knowledge you have contributed!
I wish I had put together a build blog but I’m just too busy. Sorry. If you have specific questions, I’d be happy to answer them.
The thruster power consumption was about 16 watts at 1.5 m/s speed. Speed was not constant: it would go faster on sunny days (using up to 25 watts at around 1.75 m/s) and slower on cloudy days. The hotel load was 1 watt (that includes all the electronics and the rudder servo).
Hi Damon, thanks for the additional info! 16 watts is pretty incredible for an 3mph average. As well, 1 watt per hour for your hotel load is amazing. We might have more questions for you in the future as we progress on our project. Thanks again, Mike
