Skip to main content

Making a 'Ponyo' or putt-putt boat

If you've seen the film Ponyo (or if you grew up in Asia) you may have seen a sort of toy boat powered by a very simple steam engine. This sort of boat is variously called a putt-putt or pop-pop.

They work by having a very simple boiler powered by a candle in which water is turned to steam. The steam forces water out of a pair of tubes creating a partial vacuum which sucks water back in. The distinctive pop sound comes from the movement of the thin metal boiler's walls.

I came across lovely plans for building such a boat from a drink can and a milk carton from Science Toy Maker. The explanation and videos are really clear and easy to follow and the boat worked first time. Here's a short video showing it under test in my sink:



The first step in the instructions is making the engine. It uses a drink can, two straws and some epoxy glue. If you follow the video instructions it's not hard to make. Here's the can with the lid cut off using scissors:

Then it's folded in half and held together with some tape:

Then a pattern of cuts and folds is stuck on with more tape and the can is cut in two places and two folds are made to form the boiler:

Once folded the boiler is completely flat:

Then by gentle squeezing and inserting some straws you form the boiler shape which is fixed using epoxy glue:

Finally the straws are glued into place with epoxy and bent until he correct angle. The bends are hot-glued to keep them from unbending:

Then the engine is ready for a power test.

The boat itself uses a milk or juice carton. Here's one I borrowed from someone's party:

There's a simple pattern to print out and stick to the flatten out carton:

A bit of cutting, folding and stapling and the boat takes shape:

Then you stretch the boat to change the shape of the bow:

Finally, I painted it using a spray silver paint that was polystyrene safe and inserted the engine. The engine is hot-glued in place which helps seal up around the straws and weigh the boat down.


The boat is powered by a tea light.

Comments

Stork K said…
The real challenge would be to make one the same size as the boat in Ponyo.

Popular posts from this blog

Your last name contains invalid characters

My last name is "Graham-Cumming". But here's a typical form response when I enter it: Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not. What they actually meant is: our web site will not accept that hyphen in your last name. But do they say that? No, of course not. They decide to shove in my face the claim that there's something wrong with my name. There's nothing wrong with my name, just as there's nothing wrong with someone whose first name is Jean-Marie, or someone whose last name is O'Reilly. What is wrong is that way this is being handled. If the system can't cope with non-letters and spaces it needs to say that. How about the following error message: Our system is unable to process last names that contain non-letters, please replace them with spaces. Don't blame me for having a last name that your system doesn't like, whose fault is that? Saying "Your

All the symmetrical watch faces (and code to generate them)

If you ever look at pictures of clocks and watches in advertising they are set to roughly 10:10 which is meant to be the most attractive (smiling!) position for the hands . They are actually set to 10:09.14 if the hands are truly symmetrical. CC BY 2.0 image by Shinji I wanted to know what all the possible symmetrical watch faces are and so I wrote some code using Processing. Here's the output (there's one watch face missing, 00:00 or 12:00, because it's very boring): The key to writing this is to figure out the relationship between the hour and minute hands when the watch face is symmetrical. In an hour the minute hand moves through 360° and the hour hand moves through 30° (12 hours are shown on the watch face and 360/12 = 30). The core loop inside the program is this:   for (int h = 0; h <= 12; h++) {     float m = (360-30*float(h))*2/13;     int s = round(60*(m-floor(m)));     int col = h%6;     int row = floor(h/6);     draw_clock((r+f)*(2*col+1), (r+f)*(row*2+1),

The Elevator Button Problem

User interface design is hard. It's hard because people perceive apparently simple things very differently. For example, take a look at this interface to an elevator: From flickr Now imagine the following situation. You are on the third floor of this building and you wish to go to the tenth. The elevator is on the fifth floor and there's an indicator that tells you where it is. Which button do you press? Most people probably say: "press up" since they want to go up. Not long ago I watched someone do the opposite and questioned them about their behavior. They said: "well the elevator is on the fifth floor and I am on the third, so I want it to come down to me". Much can be learnt about the design of user interfaces by considering this, apparently, simple interface. If you think about the elevator button problem you'll find that something so simple has hidden depths. How do people learn about elevator calling? What's the right amount of