India's Phat Phats: ingenious steam-powered toy boats

This short video demonstrates the iconic Indian "Phat Phat Boat," a cheap kids' toy sold at festivals. It has a tiny steam boiler powered by a bottlecap filled with paraffin with a little wick, and when powered, it poots around in adorable circles.

It's part of Arvind Gupta's lovely Toys from Trash series, which has dozens of great projects you can make at home.

PHAT PHAT BOAT - ENGLISH - 23 MB (Thanks, AviSolo, via Submitterator!)


  1. Wow. I used to play with these when I was a kid. My old man would bring them back for me!

    Yay memories!

  2. I made a boiler out of a pop can and epoxy, it was a mini steam engine.
    I wonder if I made a 1000 mini boilers could I power a small row boat.

  3. i want this! sad that kids toys so seldom use fire these days. loved my old mechano steam engine… and how about the spark shooting robots? awesome.

  4. This toy is usually called a “pop pop boat”, as at . The toy was patented in 1891, but there are reports of it as early as 1880. The heyday was in the 1940s and 1950s, declining as plastic toys took over the market.

    The video says there is an “inlet pipe” and an “outlet pipe”. That is incorrect. The steam propels water out both pipes, then vacuum sucks water back in both pipes. The main reason for having two pipes is that it makes the boiler easier to fill.

  5. I had no idea these were available to buy anywhere, but they’re great fun for kids to make. Wrap the middle of a length of metal tubing around a stick a few times to make the boiler and jets, and install it in anything that floats and won’t burn. I seem to recall that at least once we carved a boat out of a bar of ivory soap.

  6. I’ve always liked the simple version shown here:

    There are a bunch of other great projects on that site.

    I’ve also seen a version that uses a small folded-over sheet of metal (soda can wall?) as the main chamber for the water, which creates a very loud PUTT PUTT as the water turns to steam and then the walls of the chamber collapse back in on themselves (I think).

  7. i remember that the cub scout manual of my youth had a page on how to build these with balsa wood and copper coil. what a cool toy!

  8. By the way, although water goes both in and out of these tubes, it’s interesting that there is a very defined forward motion, instead of jiggling back and forth. I’m pretty sure that this is because of the directed “pushing” of the water during expansion, and non-directed “pulling” of the water during contraction.

    That is, if you tried to blow out a candle by blowing at it through a straw, it would be very easy. But if you tried to blow it out by sucking through the same straw, it would be very hard, even though you’ve got the same amount of air moving past the straw’s opening. That’s because, I assume, the air is coming into the mouth of the straw from all around the opening when sucking, instead of all going in one direction when blowing.

    Throw Newton’s third law in there, and you have a boat that travels more in the forward direction than in the backward direction on each putt.

    1. @SamSam – I am not an engineer, but looking at it, I think the motion is probably not due to slightly unbalanced directional vs non-directional push-pull motion, but more to do with the fact that it’s a steam boiler :-)

      1ml of cold water ingested, turns into 1600ml of steam expelled (according to a quick web search).
      So that’s where the small pull, big push comes from. Not that these toys approach 100% efficiency or anything, but there is clearly enough vaporizing to make plenty of motion happen.

  9. A simple diagram for a DIY version of this, using copper tubing and a candle, was featured in “Elective 6: Sailor” in the 1962 printing of the Wolf Cub Scout Book issued to all new 8-10 year-old Cub Scouts working to earn their “Wolf” rank.

    They just called it a “Jet Boat”. I think the Indian “Phat-Phat” is an excellent onomatopoeic rendering, though.

    1. I don’t think many companies want to take on the product liability laws in the US by putting out a toy that requires an open flame to operate

  10. Sadly India is now flooded with cheap toys from China and this supply is killing the local, handmade wooden toy industries. Channapatna is South India used to be very famous for toys.

  11. When I was a lad, I used to make little boats out of aluminum foil and attach a notched piece of soap to the stern (does a tiny foil boat actually have a stern?).

    Anyway, the soap breaks the surface tension of the water and this propels the boat.

    Not quite as cool as this, though.

  12. I played with these as a child in India (late 1960’s) when my dad would buy them from one of the many toy sellers who could be found at the local markets. We migrated out of India in the early 1970’s. Recently, my dad went back to India for a family visit and managed to buy one for my son. They are much harder to get now but still as much fun and keep running until the flame goes out.

    The other thing that goes with these boats are the plastic “fish” made out of thin scrap plastic sheet in the shape of a “V”. A small piece of camphor is inserted in the notch of the “V” and they are dropped in the water and as the camphor dissolves, they zip around randomly on the surface.

    Simple fun from another time and place.

  13. As a kid in India, I couldn’t buy this. But based on a book by Ya Perelman (Physics for Entertainment I or II), made one with an egg as the boiler.
    For the right kind of boiler, you make pinholes at each end, blow through one till everything is pushed through, including the yolk, dip the egg in a bucket of water and blow out the water collected within to rinse the egg out all out. Repeat till you think it’s clean. Seal one hole with tape or anything better – but non-inflammable – that you can think of. Dip the egg in water again to fill up to a point a little below the remaining pinhole when the egg is placed horizontally.
    Bend wire to make a makeshift tripod. Make a boat of cardboard from last year’s school exercise books, cover it with paper from those old books, then plastic cut out from bags. A bottle cap with oil or paraffin and a wick of cotton provides the energy source.
    Place the egg upon tripod and the whole thing in the boat.
    There’s no popping sound and jerks as in that ‘unaffordable’ phat-phat boat, just a low eerie hiss.
    Works like a charm and you feel you’ve accomplished something even if you haven’t. Hey, but it’s fun.

  14. ha this brings memories! i made one of these for my girlfriend’s birthday a few weeks after watching ponyo. putt putt putt putt
    Now i can say i learned thermodynamics for a woman!

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