July 28, 2015 | By Alec

Design challenges are always a good place to find unusual, fun and inspiring 3D printed creations, and it is already looking like Thingiverse’s Make It Float Challenge won’t be any different. Perhaps the most inspiring entry we’ve seen was developed by a Swedish engineering student known for original designs, as Filip Sjöö has 3D printed a very cool automated boat complete with desperate passenger. Filip’s boat won the third prize in the competition.

If the name of Filip Sjöö sounds familiar, that could be because we’ve previously reported on some very fun projects by his hand. The 22-year-old Swede studies engineering in Obrero, Sweden, something that is reflected in his original and often functional designs. Remember this cool and useful 3D printed dishwashing device that uses water power to clean dishes?

This completely 3D printed boat Filip has entered into the Make It Float Challenge somewhat revolves around the same principle, but like all of his designs is easily replicated as well. As he explains to 3ders.org, Filip only designed it on a whim upon stumbling on the challenge. ‘I read the description for the challenge and thought that it would be a fun competition do join. I had a lot of ideas on what I wanted to make,’ he says. And like his dishwashing device, he chose to harness the power of the water a boat was supposed to float in to give it an extra dimension. ‘I didn’t want to use electric engines or stuff like that, because that would have made it harder for other people to replicate. I thought that potential energy would be cool to use, I could use weights, but then you would have to ”wind it up”. I wanted it to move when you put it in to the water, without having to do anything else, so I came up with the idea of using the kinetic energy of the water around the boat, by simply making a hole so that the water could flow in to the boat, and the collect the kinetic energy with a water wheel,’ he says.

But that principle obviously needs a very clever design as you can’t hold a boat under a tap all the time and call it a floating boat. ‘My first thought was to use a propeller that made it go forward, but I think it would be very hard to make it move at all if you tried that. I also thought it would be fun to make a thing that squirts water when it sinks, that would be pretty cool. In the end I decided to make a boat with a man that waves his arms at the same time as the boat sinks, because that would be easier to make than the other two ideas,’ he tells us.

The young student set out on a on complicated design process that largely took place in SolidWorks – and as he never used it for a project of this size, it was mainly an educational project that took place alongside instructional YouTube clips. ‘When the shape of the hull was done, it was time to think about the mechanism in the boat. First I calculated how much the boat would need to weigh to make the water flow in the hole. I filled the boat with material up to the point where the water should flow in, material with the same density as water, in order to approximate the weight of the water that the body displaced, to get the upward buoyant force (archimedes principle),’ he explains to 3ders.org. ‘In order to make the water flow in to the boat it needed to weigh about 450 grams. You were encouraged to use coins as weights in this competition, so that was a great way to get to the 450 grams needed. To make the water wheel spin as long as possible, I made a ”lid” so that the money could lay on top of the water that was flowing in, so that as much water as possible could fit, without the water level rising so much that it stopped the water wheel.’

But of course the water wheel mechanism that makes the desperate passenger move needed to continue right until the very end, so that required some careful calculations on how much water weight was necessary. ‘[Therefore] I calculated how much water that would fit before the water wheel stopped, it was about 90 grams. In order to make the boat sink after all the water where in the boat, one would need about 660 grams. So about 570 grams of coins would make it sink when he’s done waving. Of course the arms and other stuff have some weight too, but that’s almost negligible,’ Filip tells us.

However, the water wheel itself required some careful thinking as well. Calculating the necessary rpm of the water wheel, after all, depends on a lot of factors including friction and ‘unused water’ that flows by. ‘Because of this I made a guess, of about one revolution each second. I knew the guess was a little bit low, but I figured that it was much better if the arms would go faster than slower than expected. I set the gear ratio to 1:4 so that they would go up once every 4th second, at worst,’ he says.

Upon completing his calculations, Filip began designing the water wheels themselves, but this was a slow and arduous process. The first five didn’t even work, up to a point where the student wanted to give up. ‘On the sixth water wheel something happened though, it turned! So I started optimizing the water wheel, and after a lot of iterations, I finally had a water wheel that could turn about 18 revolutions, much faster than 60 rpm though, but that was only good,’ he says. ‘Then I made all the attachments and the gears, which wasn’t too hard, but it took some time.’

Nonetheless, Filip called these water wheels the most difficult part of the whole design process, which nearly even made him miss the deadline of the Make It Float competition. ‘On the last day, a couple of hours before the deadline, my printer nozzle clogged, and I had some important things left to print, like the counter weight for the arms. Without the counter weight it would have never worked. Luckily I fixed it in time, but it was a close call. And I didn’t have much time to write the description on Thingiverse for the competition.’

With the hard part done, Filip got a bit create with the desperate passenger by using an Xbox Kinect to scan his own head, his father’s hand and his friend’s arm – creating a Frankensteinish passenger by combing the parts. ‘The last I did was to put a counter weight with a coin in it, on the arms, because they were pretty heavy. The equilibrium made them go up and down very easily,’ he adds. All of the parts used on this fun boat were 3D printed in PLA and assembled through a connector’s system similar to what you find on LEGOs. Some gluing might be needed depending on your 3D printer and the settings used, but Filip didn’t require any at all. If you want to recreate this fun little boat, you can find all the downloadable files here. There are a total of 21 parts (though the plug needs to be 3D printed twice), with total printing time being around the twelve hours (initial creation being up to forty hours!).

But the results are definitely worth the effort. As you can see in the clip below, a clever mechanism will begin to take place once there’s enough weight in the boat. Water will begin to flow through the hole in the bottom of the boat, and up through a pipe and down through a chute to the water wheel. ‘The water wheel drives two gears which reduces the speed to ¼. Then a shaft and a crankshaft transfers the energy to the arms, and makes them go up and down,’ he explains. The man, in short, is desperately calling for help until the boat sinks. Who wouldn’t want something like that in their bath?

Though Filip did not win, he was very pleased with his third place in the Make It Float Competition, and is already thinking about follow up projects that will be just as educational. ‘I’m thinking about joining the other competitions that Thingiverse have. I really learned ALOT on this one,’ he concludes. And if the quality of this entry is anything to go by, we will doubtlessly see him rise to the top of other competitions in the near future as well.


Posted in 3D Printing Applications



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