Guest MOC interviews series

LEGO® motor boat

THEME

Practical machines

Andreas Stefadouros 

LEGO builder and adventurer

Were those the longest 11 minutes of your life?

Actually, no. I was very excited to use my outboard motor in the sea, so time flew by extremely fast.

How did you get this idea? What inspired you?

Since I was a kid I dreamed of shrinking myself to be able to fit in my creations. Somewhere between that dream being a scientific impossibility and me getting jealous of LEGO’s full sized Bugatti and your team’s Go Kart, I started thinking of what I could build with my non-existing corporate budget of roughly 10 Euros.

Moving myself would require overcoming enormous amounts of friction in comparison to moving a 1-2kg vehicle so it was obvious that I would have to build something that would work in an environment with the lowest possible amount of friction. The answer was “air”,  but since LEGO flight is not possible (not yet at least), I went for water and came up with the outboard motor idea. I spent my immense budget on a one person inflatable dinghy and here we are…

How long did it take to made this motor?Did you get scared when wind gets stronger and Steering was unresponsive?

I will answer both of your questions by running you through the long process of building and testing my motor using the extremely low amounts of spare time that I have.

It all started in October 2019 when I came up with the idea to build an outboard motor for a small inflatable boat. I knew it would be a tough project because my LEGO® time is very limited. I have to tackle two jobs and find some quality time for my wife and baby boy.Time for building and testing (especially in the sea) is scarce. I created a design in my head, built it in a few hours, tested it in my bathtub and a few days later (early November) I went ahead and conducted my first sea trials.

It was obvious that my MkI motor was extremely slow, so I started thinking about solutions to make it faster. After a bit of brainstorming I came up with the MkII design which used tank tracks as belts to transfer power to the propellers.

The design worked better than MkI and could achieve a little higher rpm on the props, so… I scrapped it and never tested it in the sea. It was December and I already had MkIII in my mind (plus other projects). In MkIII I decided that using propellers built entirely from Technic elements was nice but very inefficient. Turning the boat would also be a problem since my rudder was also quite ineffective. The solution was a pair of big RC propellers that were mounted on turntables that would be able to rotate them up to 180 degrees. The two propellers would still be powered by four XL motors and my BuWizz, while the turntables would be operated by an EV3 brick. January 2020 came and once again I had time to build. I built my MkIII motor in a few hours (always build when your baby is asleep), tested it in my bathtub and everything seemed to be in order.

One week later I went to the sea, got quite wet, almost dropped my drone controller in the water so I returned home without any footage of my first successful test. I decided to wait for the weather to get warmer. The motor sat in a closet waiting and… Covid-19 lockdown. No chance of testing my motor unless I flooded the house (wife said no). My first opportunity to test the motor came in late May 2020. I drove to the beach full of joy for my test and positioned my drone to capture the moment.

Everything was great until I dropped my EV3 controller in the water (turned out that handling one cellphone for BuWizz, an EV3 IR controller and a drone is quite hard). With my steering dead the test was over (at least I got some footage). Returned home, cleaned my EV3 controller and got it working again, so I was ready for my little-big adventure (FYI, that’s an old PC game) as soon as I got the chance.

One week went by and I returned to the beach to attempt my adventure. This time however, I wasn’t alone. An uncle of mine accompanied me with clear instructions : in case anything goes wrong get in the water and save the LEGO…

So, after all these months of getting wet, waiting, waiting some more and dropping controllers in the water, when the situation of my steering being unresponsive came up I wasn’t afraid. I was furious! No problem on this planet would get in my way of completing my adventure. I would see this through even if I was surrounded by great white sharks that hadn’t eaten for a month! Would I suggest that anyone else does that? No… don’t…

When do you plan to sail to Salamina?

I was thinking of Spetses, but Salamina is closer… challenge accepted…

What was the biggest challenge during building?

Finding a way to handle the amount of torque I needed to make things happen and mounting the whole thing on a squishy inflatable dinghy. Finding time was also tough. Always is…

What next can we expect from you? Besides sailing to Salamina

On the outboard motor front, expect MkIV. I already have the plans in my head. Just need to make them happen. If it all goes well I will be able to raise the prop rpm even higher and also use my BuWizz in ludicrous mode. In MkIII ludicrous mode tends to destroy some of the gears. I found a way to correct that.

I’m also revisiting a ship I built two years ago (before I got myself a BuWizz) and have plans to build an even bigger one. I think it’s obvious I enjoy water based projects.

In general, if things pick up in my YouTube channel, you can expect a show inspired by The Grand Tour, but instead of cars you’ll get LEGO in all shorts of crazy scenarios!

Thank you Andreas Stefadouros 

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