When the Family Car Is a Solar Powered Boat

What do you do if you live off the coast of Panama and you need to get the family around? If you’re Jaimie Mantzel, you build yourself a solar powered boat… or three.

Mantzel had previously built a 16′ catamaran sailboat with a plywood and fiberglass hull, which he later converted to a solar powered motorboat. Taking what he learned, Mantzel built a larger pontoon boat with many clever innovations. He also started on a huge house boat to live on, but that’s another story.

The Hull

This time, instead of starting with plywood, Mantzel formed his own molds to create fiberglass pontoons and a frame for his boat. Fiberglass is strong and light weight. Each pontoon has three separate compartments, which limit how much water the boat takes on in case of hull damage. There is a hatch in each pontoon for storage.

Solar Panel Roof

The roof of the boat is a movable frame holding seven 250 Watt solar panels, for a total of 1750 Watts of power. A clever mechanism allows the roof to pivot at the front and to be lifted and tilted from the rear. This can be used to maximize the effective exposure of the panels to the sun. In addition, Mantzel would like to use the whole roof as a sail to give him the option of moving under wind power.

Motor

For the motor, Mantzel hacked together a broken outboard motor purchased for $20 and a 24V Leeson DC electric motor, rated for 1.5 HP. He removed the busted gasoline engine and swapped in the electric motor. Mantzel had to extend the length of the motor to reach the water. So he used a pipe to lengthen the drive shaft, and made a fiberglass section to connect the motor on one side and the lower section of the old outboard on the other.

Motor Control

The control of the motor couldn’t be much simpler. A pair of hand-made switches let Mantzel connect either three solar panels, four solar panels, or all seven.

The outboard Mantzel got has a clutch inside that only gives power in one direction. So for reverse Mantzel simply turns the entire motor around.

Performance

Mantzel recently tested the boat on a 30 mile all day cruise, and was quite pleased with how everything worked. Although it is not as fast as a typical power boat, the motor is very quiet compared to a gasoline engine. Of course the cost of fuel can’t be beat. The boat fits with the lifestyle Mantzel works so hard to lead:

“If I had used a gasoline engine and a normal ‘gringo’ boat, I could have gotten there and back in 2 or 3 hours, but the thing is that that would have cost money… and this doesn’t… When you don’t need money to do things, life looks different.”

Mantzel gets pretty good speed even on a cloudy afternoon; the speed is even better in full sun between 10am and 2pm. He figures he averaged 6mph while traveling at non-optimal times of day. He’s not sure what the boat’s top speed is yet. He has temporarily disconnected one solar panel, because all seven panels slightly overpower the motor. Still, he’d like to test using all seven solar panels with full sun on the next trip. The motor seems to be handling everything, no problem.

Future

Mantzel plans to add boards across the front of the pontoons for a deck, and netting in the back. He’s also adding batteries to work with the charge controller he already installed. He might store batteries in the pontoons.

Mantzel is still working on the mechanism to tilt the solar panels to capture maximum sun, or to use as a sail if there is no sun and good wind. Mantzel says the tilting sail idea is, “fully intact and being implemented.”

A boat like this might not be for everyone, but it does show what you can do with a little ingenuity and a lot of hard work.

“There is a massive, massive difference between making something for fun or that’s a proof of concept,” says Mantzel, “and making something and using it and putting your life in its hands.”

Watch the video below for quick walk through of Mantzel’s boat design.