Amazing Toy Steam Boat, no moving parts

Sometimes you run into things that just cry out “elegant”. Some are so simple as to look like nothing at all, crude bits of nothing. Those are my favorites.

This one is a stellar example.

It has a boat ‘hull’. A Candle. And a bit of bent tubing. That’s it.

IMHO, it is best described as a “pulsating heat pipe” that is open ended with both ends under the water. A loop of pipe near the candle gets hot and when steam forms, shoots a load of fast water out the back. The steam cools in a cold section of pipe, and cold water is sucked back into the pipe, eventually hitting the hot part, that puffs it out again. High speed straight out, low speed diffuse origin in. Differential thrust / drag. The boat goes forward.

I have to wonder how large one of these could be made… It just cries out to be tried at the ‘full scale’ level. Perhaps with larger tubes it would need a feed pump to keep things more stable (or more quiet ;-) but in any case, a ‘steam jet powered boat’ would be a bit fun. Especially one that worked on any old fuel you had (even trash) and had no lubrication or maintenance (other than dumping the ash box…)

A kind of pulse jet for boats…

About 1/2 way down this page:

Toy Steam Pipe Boat

Toy Steam Pipe Boat

The same site has a ‘cannon’ made from film cans… ( I knew I was saving them for something ;-)

Someone has a great imagination, a sense of fun, and way too much time on their hands…


As much as it reduces the elegance, I have to wonder if a bit of differential drag in the two pipes would lead to better water pumping all the way into the hot part. Perhaps as simple as a small bend in one leg, or a slightly pinched exit from one of the pipes? For a large design, perhaps putting Tesla Valves in the pipes would lead to one way water in / steam out asymmetry? It would still have no moving parts, and be very very elegant, though lacking some of the ‘crude charm’ aspect… It would also allow for differential optimization of the steam nozzle vs water inlet configurations and orientations. Water scoop forward and small, steam nozzle rear facing and larger… Or perhaps that’s just putting a load of yellow paint on a lily…

I did find an online patent for one with one end of the tube completely sealed, but that seems to lack some desirable features, like having the mass flow always be from front to rear.

Frankly, IMHO, this just cries out for someone to make a full sized version. I’d like to see a State licensing authority try to figure out where the ‘engine’ was and what to classify it as.

It also looks like other folks have played with the idea as well. This video looks like ‘similar, but different’:

While this one is a twin engine model:

This Canadian is claiming the world speed record. It looks, from the tube count, like he has a multiple engine job. My count of the rear facing tubes would make it a 4 engine model. However, it also has a forward facing tube on the right side, so there may be some “special” design in use… AND… In this other video we see what is likely the same engine. It is described as a single engine, but with multiple tubes.

IF (and it is a very big if) the scale speed ‘scaled up’ with full size, that would be a respectable boat speed. Even if you only get 2 to 4 MPH out of it, it would still be fun on a lake.

The test of multiple hull designs and tests with variations in engines, engine shown clearly:

I’m left to wonder how I could have lived all these years an not known of these before…

This page claims they have been around for over 100 years:

Though it was forgotten by most until about 1982:

Basil Harley seems to have rediscovered the 1891 invention of the pop-pop boat about 1982, after having written several articles on pop-pops for Model Boats magazine during the 1970s. In a 1975 article, Harley mentions a similar boat seen in a French journal from 1880. The pop-pop boat as we know it originated in an 1891 British patent for water pulse engines by an inventor named Thomas Piot. The patented engine was of the coil type.

The popularity of the boats spread quickly, however, and they were soon being manufactured in many countries. In Toyshop Steam, Harley mentions a series of boats made in the first decade of the 20th century by the German toymakers Ernst Planck. In 1916 a US patent was granted to Charles McHugh for the diaphragm type engine. (See patent document.) The McHugh patent was specified for use in toys, while the Piot patent was apparently left more general. The addition of the diaphragm seems to have produced a toy with great appeal, as evidenced by the large number of advertisements found in magazines such as Popular Science and Boy’s Life (see illustration). The German name for the boat, toc-toc, originated as a product brand name for a diaphragm-boilered boat in the late 1920’s, while they have also been called put-put, phut-phut, and pouet-pouet boats elsewhere.

One passage implies that the Tesla valve version with inlet forward, jet rearward, would be a significant improvement (as would be some insulation on all those exposed hot surfaces …)

In The Flying Circus of Physics, Jearl Walker pinpoints the crucial quality that makes the pop-pop boiler function:

The candle converts some of the water in the boiler to steam, which then pushes the water column back through the tube to emerge behind the boat in a jet. Upon leaving the boiler, some of the steam condenses in the cooler tube and contracts, thereby pulling water back into the tube. However, the key feature is that the water entering the tube comes from a hemisphere of directions, not from a single direction. There is a net propulsion forward because of the asymmetry in the jet emission rearward and the inflow from all directions in the rear hemisphere.

This strongly implies that even more asymmetry would work even better. Alternatively, a nozzle designed to entrain water during the steam expulsion to increase the rearward mass (i.e. through a venturi and flare), while favoring water intake from the front during the ‘reload’ stage, could also work well.

My vision of it would have a small scoop pointed forward, pipe to the boiler area, a Tesla Valvular conduit to assure water only flowed in that way, the boiler, pipe toward the rear (no valve) ending inside a vented flare such that the steam jet would entrain water mass rearward (like the steam injector pumps in steam engines). Some water would still be able to reverse flow up the exhaust pipe (to help prevent vacuum collapse of the system, if nothing else ;-) but at speed, more would come from the front of the craft.

Steam Injector (a kind of pump)

Steam Injector (a kind of pump)

For those not familiar with it, the Tesla Valve has no moving parts, very fast response time, and acts as a fluid diode allowing substantially one way fluid flow only. The valve is shown in detail on the top, mounted on a turbine housing in the bottom:

Tesla Valve on a turbine housing

Tesla Valve on a turbine housing

More than you would ever want to know about it here:

Patent description (with the above image) here:

There is also a tease reference to someone having made full sized boats…

And then there is Peter R. Payne, whose interest in the engineering aspects of the water pulse-jet led him to some fascinating experimentation using them in full-sized boats. If you want to take your construction project to the leading edge of the technology, Payne’s work is the handbook for your efforts.

I found four of his papers here:

But the type and size means it will take me a while to slog through it and find if there is a mention of the full sized performance.

UPDATE: In reading one of them, it includes performance data and even a picture of the boat.

And this biography: sure sounds like an interesting fellow I’d have loved to know, but he, too, has met his end.

In it there is another tease talking about a 14 foot scale of boat powered by one of these engines.

At that point the trail goes muddy, and this post is getting a bit long. OK, perhaps someone else can put in the time to find an image or performance data on the larger scale boat.

It looks to me like there ought to be a fairly easy path to some improvements that would make this a very workable personal sized craft with near zero maintenance and very long life. The big question I see would be fuel costs (and perhaps sound levels). It would also make a good gimmick in an ‘alternate timeline’ story where folks in, oh, Egypt of the Pharaohs invent a steam boat from copper pipe and oil lamps… and dominate the world…

At any rate, now I have another toy I want and will likely never have ;-)

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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29 Responses to Amazing Toy Steam Boat, no moving parts

  1. Another Ian says:

    E.M. These have been around a while. Dad (born 1897) in his youth was playing with one on a stock trough and was asked “Was it a bumboat or a battleship”. And he watched us use them. As I have with our boys.

  2. Gary says:

    I recall seeing instructions for building these in the 1960s, probably in a Boy Scout publication.

  3. adolfogiurfa says:

    Good idea for my grandkids!

  4. conscious patrick says:

    how will these be maintain in case of breakdowns, or failure in steam generating?

  5. Chuckles says:

    baby brother of the Flash Steam boats that were popular during my misspent youth. They used serious blowtorch systems directly on copper pipes as the boiler to generate the steam. The world record for a model flash steam boat is about 120mph.

  6. H.R. says:

    How about putting your LP gas bar-b-que on a full size hull and then you can cook lunch while cruising about the lake – 8″ pipe over the back of the burners and meat and veggies of your choice on the front of the grill.

  7. Jason Calley says:

    If you ever get a chance to watch the Japanese animated movie “Ponyo” (which I recommend, especially if you have a young offspring, or grandkid or two to watch with you) you will see a full sized –well, child-sized anyway– pop pop boat with a couple of children in it. Well, OK, an animated drawing of a pop pop boat. Well, OK, it was a toy at first, and then magic turned into a larger boat. But it was very good magic! Worth watching.

    The idea of the ancient steam boat is neat! Lot’s of good alternate history stories in that! I am reminded of something I ran across some years back, the African Steam Engine. I have spent many hours considering possible slightly higher tech versions of the African engine, just in case the wife and I ever get our cruising canal barge boat.

    OK, let’s see, the Egyptians could have built steam boats. And a Rogalo hang glider is just two lateen sails mounted on a common boom. Can an ancient Egyptian aircraft carrier be far behind?

  8. Æthelwold of Wessex says:

    An aquatic pulse jet?

  9. E.M.Smith says:

    @Jason Calley:

    Love that link about the “stove engine”. Just the thing for “After The Fall”…

    Also found this quote rather “illustrative” our our Progressive Friends approach to ‘saving the village’…

    When this break-away region was forcibly re-united with the UN-approved ex-colonial “official government”, our tyrant disappeared while under house arrest. Under a policy of “progressive” Westernization loudly supported by all right-thinking Western Liberals (who had never visited the place), the stove-engines were replaced by outboards from Western manufacturers.

    The cost of a high-revving, small-propped 10-hp outboard to do the same job as a slow, large yuloh indebted a boat family for life. Fuel for these outboards had to be imported since the local low-quality (high sulfur content) oil was refined abroad and imported as gasoline. The imported outboards didn’t employ the local people. All the profits from the outboards and fuel went back to the Western World at the expense of the Third World local population (naturally).

    The “progressive” Western and Liberal-approved government actually made stove-engines illegal. The reason was supposedly that they “used valuable hardwood resources for fuel”. They did not, but the propaganda appealed to Liberal “rainforest savers” who were just then getting started. Actually, the hardwood was coveted by Western upscale furniture and piano manufacturers who became responsible for greater rain forest harvesting than ever before 1983. And, of course, locally-made stove-engines challenged the market for outboard sales – and continual sales since no outboard repair facilities were set up. Aid business as usual, courtesy of the World Bank and USAID.

    FWIW, if you read the linked articles from Peter Payne, he has some significant improvements. Also one that gets you thinking about it as a kind of Stirling Engine with a ‘water piston’ (and a version using fuel burning inside the chamber… ) and a ‘water pump’ version.

    This has led me to ponder the benefit of a simple lift pump. At the foot of a pipe, a check valve (no more than 25 or so feet down, otherwise the vacuum lift will fail), then the “boiler” of a hot thick metal plate with some contact area enhancing surface treatments. Then, sharing a Y fitting to the boiler with the intake, the outlet with another check valve that lets the steam push the water much higher. Prime and fire it, you ought to get a decent pump. I’d enhance this with a heat exchanger (ala more formal Sterling engines) just about one “stroke” outside the “boiler”. This ought to work better than the ‘accidental heat storage’ of the long exit pipe. By doing this, the ‘back and forth’ of the water is reduced (reducing friction losses) and the heat recovery is better (reducing heat losses in the long pipe…)

    (I know, it would be better with a picture… I’ll try to draw one up).

    The end result ought to be a fairly efficient water pump with a 20 ish foot lift and fairly high head pressure that could be built by anyone with simple plumbing skills. I’m sure you can see the utility of this in 3rd world countries and “emergencies”… That it can be fired with anything that burns, or even just a large mirror…, would be nice too.

    Hmmm…. I think I’m feeling a ‘theme’ coming on… Making the most advanced results possible with the most primitive skills and materials possible and publishing it to the world. Rocket Stoves, that ‘stove engine’, the ‘water piston pump’ and the ‘put put boat’…

    At any rate, if you would like to have a thread to mull over such things, and / or make a communal ‘design point’ for things like the ‘water piston pump’, let me know.

  10. Chuckles says:

    Jason C, fascinating story, may I suggest this link as a better alternative?

    While the story has some very valid points about shipping ‘inappropriate technology’ to 3rd world destinations, there are some fairly odd and sometimes contradictory claims floating round in there, but there are some nuggets of truth that strike a chord as well. So who knows, at least parts of it could be true. Great story nonetheless! :)

  11. E.M.Smith says:


    One of the links ( I think it was the one from Jason) had a reference to cooking dinner over the ‘boiler’ … great minds think alike ;-)

    @Conscious Patrick:

    I don’t think a simple pipe is going to break down much, but if it clogs up with scale, I’d just put in a fresh one while I fixed the old pipe…

    @Jason Calley

    A search on ‘Stirling water piston pump’ gives some interesting pages:

    Click to access FK_AO.pdf

    Much lower temperature devices (often using air as the heated fluid) so not quite the same.

    Still, I have to wonder how many archeologists would recognize one of these if they found it in a ruin. It would just look like some broken pipes with odd shapes and maybe a ball or flap valve. Not the stuff to make an archeologist think of overturning all the history of heat engines and the ancient world…

    I think I’m going to have a cuppa tea and contemplate low stress ceramic engines and no moving parts water pumps for a while…

  12. Jason Calley says:

    @ Chuckles Yes, better link. Thanks! Like you, I wonder just how much of the story is reliable. I am guessing that the basic idea may very well be possible though. Good story, either way!

    @ E.M. “if you would like to have a thread to mull over such things, and / or make a communal ‘design point’ for things like the ‘water piston pump’, let me know.”

    Might be fun! I rather like the idea of low tech devices. I mean, anyone — these days — can buy a computer that will play music or do calculations, but how many people can make a record player out of junk they have lying around? Or calculate complex math problems by hand? I find that sort of skill MUCH more impressive than doing the same job with high tech. If you start a thread on such ideas, can you call it something like “Low Tech Miracles”? Certainly low tech steam engines should be there and some of your no-moving-part water pumps. Probably some water ram pumps too. Probably the Ragged Chutes air compressor. Maybe the Minto Wheel.

    By the way, good info on the liquid Stirling! If you used a ferromagnetic fluid in that and pumped it through a magnetic field with some pickup coils, I wonder could you get electricity with no moving (solid) parts? For example, imagine that the hot and cold chambers (which are alternately partially filled and emptied) had a magnetic field and coils of wire wound around the chambers. As the ferro fluid fills and empties, the total flux passing through the coils vary and you get power out.

    You say: “I have to wonder how many archeologists would recognize one of these if they found it in a ruin. It would just look like some broken pipes with odd shapes and maybe a ball or flap valve.”
    One of the more peculiar ideas about the Great Pyramid of Egypt is that it was a giant water pump. The idea was first bruted back in the 1929’s I think. I admit that I am very much unconvinced. On the other hand, did you ever wonder where the name “pyramid” comes from? It seems to mean “fire in the middle.” Maybe that was the fire thaat ran the pump? Not sure if I am kidding or not… :)

  13. Al says:

    I had first seen this in a children’s encyclopedia in the early sixtees. (Knewnes encyclopedea?). I was maybe 12 years old and i was so fascinated by the design. I always meant to make one. I’m 60 today and i think I ll be building one for my grandsons. My wish would then come true

  14. Don Ross says:

    There was a company named Pursuit Dynamics that was intending to produce a steam powered motor for pleasure boats. It was to be based on a steam powered waterpump that I believe was designed by a guy called Alan Burns. I don’t think it ever made it to market.

  15. adolfogiurfa says:

    “I have to wonder how many archeologists would recognize one of these if they found it in a ruin. It would just look like some broken pipes with odd shapes and maybe a ball or flap valve.”
    They would say: “It´s an object of cult” and , if liberal: it was used to slave the poor….etc.
    Every time I hear archeologists I remember critics of art explaining a painting. EVERYONE LIES, the same in science, but it is “cool” and if enough indulging (and leftist) your receive the Nobel prize!

  16. xyzlatin says:

    I remember having a tiny toy put put boat about 6 inches long when I was small. It was in the shape of a tugboat. It had a tiny candle and I used to place it in the concrete washing tubs. This is about 1950. I was fascinated by the sound and the light.

  17. Jason Calley says:

    @ xyzlatin Is this it?

  18. Thanks for reminding me of a really neat little 10 inch boat that I had long ago in Wales. Instead of a candle it had a little burner with a wick. The fuel was methanol laced with a foul tasting blue substance so that folks would not be tempted to drink it!

  19. R. Shearer says:

    Very interesting..

    You probably like the “simplicity” of the vortex tube too, which separates a compressed gas into cold and hot streams.

  20. Jason Calley says:

    @ R. Shearer Neat device! If you were to gang a few of those in series (use the cold air from one to pre-cool the intake air of the next) I wonder what would be the practical lower limit of temperature. Even if inefficient, it would be nice to have a device (with no moving parts!) that you could hook up to an air compressor at home and get liquid nitrogen from.

  21. E.M.Smith says:

    @Jason Calley:

    As I remember it, they device works by ‘sorting’ molecules by energy level. At each stage you get a less diverse batch to work with, so need a highly insulated ‘pause’ for the energy diversity to build up again. (Don’t know how long that takes… could be milliseconds…or minutes…) So insulation losses will be an issue.

    Also, as you approach very low temps, the available ‘range’ to sort is less. It will get harder to get colder.

    Don’t know if those two effect put liquid N2 off limits, or just make it very expensive. Some fancy math would answer it, but it might be easier to just gang up 10 of them and measure the data points then plot ;-)

  22. Jason Calley says:

    @ E.M. “At each stage you get a less diverse batch to work with, so need a highly insulated ‘pause’ for the energy diversity to build up again. (Don’t know how long that takes… could be milliseconds…or minutes…) So insulation losses will be an issue.”

    Oh, that is fascinating! IIRC practically all of thermodynamics rests on the (Gaussian?) distribution of energy among the various molecules. If it is possible to get gas with a non-standard distribution of energy levels (even if only for a second or two) can you do something like make heat flow from cold to hot?

    Where’s my perpetual motion steam engine?

  23. E.M.Smith says:

    @Jason Calley:

    Well, one interesting area I’ve not pondered much is that you get TWO streams, one hot one cold, each sorted out of the other. So you can have both cold sources and drive heat engines… As you start plumbing these together the opportunity for a lot of ‘perpetual motion ideas’ runs rampant. But are any of them non-scams? Well, as you have all that lovely ambient energy, maybe not… but it comes down to the SEER of the device. Can you get more energy ‘available’ by sorting the molecules than it takes to do the sorting? (Keeping in mind that both the hot and cold poles have something to work with… )

    In a strange twist (or a least an uncommon one for me): I have no idea…

    I suspect that the mechanical losses from the air pumping would be high, but could some of THAT be recovered and recycled too? Is there an efficiency trick we haven’t found yet? Then what? How about using some electromotive effects to improve the sorting? What then? It’s a black hole of interesting muse that I’ve avoided lest I end up on the wrong side of the event horizon building perpetual motion machine test cases ;-)

    And what happens if you take slices out of the vortex? Narrow bands of ‘just this energy’? What is different about gas in ONE band? Anything? Oh dear, I’m getting near that edge again ;-) I mollify myself by assuming that a bell distribution reforms nearly immediately but with a narrower bell shape… and just offset in one direction.

  24. Jason Calley says:

    And that, as you know, is the big question here. Certainly as long as the kinetic energy of the molecules is spread out in a normal kind of distribution, thermodynamics is going to win. Always, no argument. Any energy gain from splitting the hot and cold is going to be supplied by the energy going into compressing the gas. But I do have that nagging feeling… I need to think about this.

  25. Another Ian says:


    Forgot to mention that, in the small tube kids type, you can sometimes get some hellish vibrations, which might be interesting in anything larger.

  26. John F. Hultquist says:

    Catching up on my reading. Never saw the boats mentioned here, but did have one of these:

  27. Brigid says:

    Thanks for linking to my Granddad’s memorial page. (Peter Payne) I love that the internet has allowed people to stay familiar with his work even after his death. He was an amazing guy.

  28. E.M.Smith says:


    Well, he did some interesting work!

    BTW, liked the artwork on your site. Noticed you have a Celtic section:

    We’ve a fair number of Celts (and some “honorary Celts” too ;-) hanging out here. I’ve put up a few historical digs into Celtic history in some postings (just web search on “chiefio Celt” or put “Celt” into the search box on this page) but the most recent one you might enjoy is here:

    Feel free to ‘hang out’ and get to know some of the folks here… I think they will like your artwork too ;-)

  29. Science Toys says:

    Great Science Toy for the DIYer. Thanks for sharing

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