A Putt-Putt Boat.


Putt-putt boats are model boats powered by a very simple, unique steam engine and they make great weekend projects for construction.

Credit for this design goes to David Waters and you need to refer to his original construction article for the finer details.

There are also many other neat designs of Putt-putt boat. If you can solder then this all-metal design looks great. Or for something more simple this great idea, uses waxed milk cartons for construction.

A simple Wooden Putt-Putt Boat

 

 

 

 

 

 

 

 

David's design used a wooden hull and wheel housing fitted with a copper 'pot' boiler. There are 2 exhaust tubes and the engine also featured a thin diaphragm skin which made the engine produce a nice clicking noise when running.

 

 

 

 

 

 

 

 

A chunk of 2" thick wood was marked out with the inside and outside hull profile. The profile was cut out using the band-saw but before this a 12mm slice was taken from the lower face to make the base.

The Inside and Outside Hull Profile

 

 

 

 

 

 

 

 

The inside was cut out first, but because the band-saw was being used the cut had to be started outside the profile, this cut was taken along the bow line.

After removing the inside material the bow was glued back together and the base glued on.

 

Hull being glued and clamped

 

 

 

 

 

 

 

 

Sanding the Hull Profile

Once the hull was glued it was shaped to the final profile using the band-saw and sanding disc.

The angle of the deck was cut first and then the outside hull profile.

The sanding disc was used with the table tilted to get a slight angle to the sides.

 

 

 

 

 

 

 

 

Drilling the exhaust holes

The 2 holes for the exhausts were drilled by hand. After the first hole was drilled a spare drill was placed in this hole to allow the second hole to be drilled roughly parallel.

 

 

 

 

 

 

 

 

The wheelhouse was made from off-cuts of wood as shown. The portholes were cut with a 19mm hole cutter.

The size of the wheelhouse was based around a tea-light.

 

 

The faceplate on the lathe was used to bore the wheel house roof to suit the chimney which was made from a 22mm piece of copper pipe.

The floor of the wheelhouse was also bored to hold a tea-light candle.

 

 

 

 

 

 

 

 

The engine was made exactly to David's design and building instructions can be found here.

The 22mm plumbing fitting was skimmed in the lathe to give it a true edge. A 0.02mm piece of copper shim was used to make the diaphragm and the whole assembly was silver-soldered together.

It was planned to fire the boiler with a small night-light or tea-light, rather than the original spirit burner.

The Putt-Putt Engine

 

 

 

 

 

 

 

 

To assemble the boat, first wheelhouse was glued in place without the roof. Then the engine exhausts were threaded through the holes in the base and the engine positioned in the wheelhouse. Epoxy glue was used to seal around the exhaust and keep the hull watertight..

After this the roof was glued in place.

Engine Installed

 

 

 

 

 

 

 

 

 

 

Wheelhouse complete

 

 

 

 

 

 

 

 

 

 

The boat was then finished in several coats of Teak oil to smarten it up and make it watertight.

A rudder was fitted by drilling a vertical hole between the exhaust pipes and fitting a small (2.4mm diameter) piece of copper pipe. Inside this pipe a brass wire was inserted which was a sliding fit in the copper. This wire had a blade soldered to the bottom and it was bent over at the top, as shown, to form a handle.

Boat Rudder

 

 

 

 

 

 

 

 

 

 

The finished boat with burner installed

 

 

 

 

 

 

 

 

 

 

On the first test run the boat moved along but didn't produce the pop-pop noise from the boiler diaphragm. More heat was tried in the form of an Esbit fuel tablet, but this did nothing except set light to the cabin.

The other problem was that the boat didn't sit level in the water it was very front heavy.

 

 

 

 

 

 

 

 

To get the boat sitting level 2 brass weights were glued into holes drilled in the underside of the hull.

To try and get the boat to make more noise a thinner brass diaphragm was soldered to the boiler but this made no improvement. However the boat ran quite nicely anyway, just quietly.

Hull weights

 

 

 

 

 

 

 

 

Putt -putt boat out on the wheel barrow lake.

Cutting through the waves

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