Make a Boat Powered by Fire.

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Introduction: Make a Boat Powered by Fire.

About: The answer is lasers, now, what was the question? If you need help, feel free to contact me. Find me on Reddit, Tumblr and Twitter as @KitemanX

There are many ways to power a boat - propellers, aquajets, sails, powerful fans, turbo-jets, rockets, and pulse-jets.

There are few ways, though, as gentle and serene as the warmth of a candle.

Step 1: What You Need.

Fire-boats need two important properties - to be light, and non-flammable.

My Clubbers used foil pie-tins as the hulls of the boats, kitchen foil as the sails and tea-lights to provide the heat.

We have, in the past, had success with normal-sized candles trimmed to only half an inch in height, or small clusters of birthday candles.

Step 2: Construction

Making a fire boat requires no specialised tools. In fact, it requires no tools at all.

A certain amount of intuition is also desirable.

Tear a piece of the foil to a suitable size, and fix it to the side of the pie-tin by scrunching the edge of the foil along the lip of the tray.

Curve the sail over the top of the boat. If it droops too far, add a crease or curve along the middle of the sail to ~~stop it drooping~~ add structural integrity.

Stand the candle in the boat, and you're ready to go.

The photos in this step are of the fire boats made by my Science-clubbers, before they took to the water. Some required tweaking, but they all worked to some degree.

Step 3: The Circular Fire Boat.

If the sail of a fire boat is not level, it will tend to spin.

This effect can be used on purpose as well - setting up two candles and sails facing in opposite directions on a circular metal lid created a boat that spun on the spot.

The clubbers had the idea that the idea could be used to make decorations which floated and spun in garden ponds or pools during a barbecue or garden party - the shiny foil sails would cast changing reflections around as the boats spun.

Step 4: Float Your Boat.

To see the fire boats working to their full potential, they need calm. Calm air and calm water.

We poured shallow pools of water into plastic trays and left them to settle. We also closed all the windows and doors to prevent draughts, and walked slowly so that the breeze of our passing wouldn't disturb the boats.

Place the boat at one end of the tray and light the candle.

As the candle burns, it heats the air around it. As you are probably aware, warm air rises. This is a convection current.

When the rising air hits the sail, it is deflected from its vertical path, which exerts a small, but real, force on the sail. Since the sail is fixed to the boat, the boat moves.

This video shows a couple of the boats my clubbers made:



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    74 Discussions

    i made one too.home toys.it rained a good amount and at a place on our top floor of the house some water got stored.i tried it there and worked.thanks!good luck for your next instructables.

    1 reply

    It's the deflection of convection currents - see step four.

    I paid attention at school - this is a logical (but not very useful!) combination of heat transfer (convection) and Newtonian mechanics (action and reaction).

    Science+imagination=Instructables.

    Genius! I enjoyed this very much, good work! I have two comments:
    Firstly, Newtonian mechanics (physics) coupled with fluid buoyancy effects (Archimedes) is causing the propultion. Convective heat transfer only causes fluid buoyancy (of the air) which has an action/reaction with the sail.
    Secondly, could you consider rather funnelling the hot air into a converging tube that draws air under the boat allows the hot air to push against the water? This should provide a serious increase in propulsion! I have seen such a tube made from a hollow kettle element, but a crimped copper tube should suffice. Any thoughts on such improvements?

    I haven't re-visited this project in a couple of years - feel free to use it as the basis of your own, improved fire-boat.

     Ahhh....I have a great imagination. Maybe I'll start paying attention now...

    THANK YOU SOOOOOOOOOOOOO MUCH!!!!!! I'm doing this in school for science and I'm happy I went on this website instead of just youtube!!! :D

    1 reply

    I think it would look just great if one made a ton of these and let them loose on a pond or pool at night. As long as they cleaned up afterwards of course.

    i made on of these with the top of a jam jar and my homemade ultra candle! i put it in the kitchen sink and tried it out it worked ok and i only stopped it when the fuel in the candle started to boil and shot bits of it everywhere so i had a fireball in the sink with my alfoil starting to disintergrate. so i blew it out and decided never to use the candle again. lol good times... good times...

    2 replies

    homemade candle... but the fuel caught on fire and boiled... not the best thing to have in you're sink.

    you could have a weight on one side, that will make the boat move, instead of using those 'ugly' sails, apart from that GREAT design!

    1 reply

    If you read it, the sails are the whole point...