First test of a steam model of a Murray River Paddle boat.

[Tony Bird]

Hi,

Yesterday I had the opportunity to try out the steam model of a Murray River Paddle boat I made in a very small boating pond. A video is at:

https://youtu.be/K2IOAPcVOZY

I was quite pleased with the result as I have never made a model paddle steamer before.  The model has a reasonably small turning circle but the paddles do not seem to absorb much of the engines power so I am wondering if larger or more paddle blades would improve its performance.  Any suggestions?  Maybe for the models next run I will try with the existing paddles lower in the water.

Regards Tony.

[DamienG]

    Very nice looks quite stable 

[Delaunay]

  Hello ;
Un petit bateau bien sympathique !
Cordialement

A small very nice boat! : bravo
Kind regards
François

[Bierjunge]

You are telling that the paddles doesn't consume much of the engine's power. In the video, the engine seems to run at very high revs and sounds more like an internal combustion engine.
I would therefore guess that you have a very short transmission ratio between engine and wheels. Instead of modifying the wheels, you could simply try a longer transmission ratio instead to make the engine spin lower at a higher load.

[Tony Bird]

Hi,

You are telling that the paddles doesn't consume much of the engine's power. In the video, the engine seems to run at very high revs and sounds more like an internal combustion engine.   I would therefore guess that you have a very short transmission ratio between engine and wheels. Instead of modifying the wheels, you could simply try a longer transmission ratio instead to make the engine spin lower at a higher load.

The engine design was for a simple small light weight unit that could be mounted low in the hull whose gear ratios could easily altered by changing the size of the pulleys.  The ratios at the moment used are worm wheel 18:1 and the pulleys 1:1.  As the engine is more than capable of powering the size of paddle being used lower ratios could be used so conserving steam or as I will initially try lowering the water line so more paddle is in the water, at the moment about 50% of the paddle blade enters the water.  The idea being to get more speed with possibly less steam use.  It is all a bit of an experiment!  As the engine is only single acting so won't self start it is better if it runs a little fast but not as fast as it does, I might try mounting it on rubber to reduce the noise it makes.

Regards Tony.

[Delaunay]

  Hello Tony ;
Une augmentation du diamètre des roues et du nombre de palettes devrait avoir un meilleur rendement, non ?
An increase in the diameter of the wheels and the number of pallets should be better, no?
  François

[kno3]

The first things I would try would be to lower the engige to paddlewheel gearing ratio (would also savesteam) and to make sure the paddles go deep enough in the water.

[Delaunay]

Bonjour ;
Je ne crois pas que d'augmenté la profondeur de pénétration des roues soit une bonne idée, car celles ci, en position de sortie, vont faire frein.

: D Hello;
I do not believe that increasing the penetration depth of the wheels is a good idea, as these two, the output position will make brake.

Cordially
François

[Tony Bird]

Hi,

The first things I would try would be to lower the engine to paddle wheel gearing ratio (would also save steam) and to make sure the paddles go deep enough in the water.

I have tried ballasting the hull until instead of two thirds of the blade entering the water all the blade does.  On test in a plastic box the engine runs slower and more water is being moved.  Having never made a steam powered model paddle boat before it is all a bit of an experiment, the engine is single acting with a worm wheel ratio reduction of 18:1, the pulleys used are 1:1 so by trying smaller pulleys on the paddle axle I can reduce the 18:1 reduction easily.  I intend the leave the gear ratio as it is until further tests on a pond.  As it stands at the moment if the boiler is filled and brought up to pressure and the Sterno tray filled again the model will run continuously for around 15 minutes when the Sterno runs out leaving the boiler about a quarter full.

It might be some time before the model gets into a pond again, and it might be in foreign parts as we are taking a model railway layout to an exhibition in a few weeks and as there is plenty of room in the trailer I will be taking the paddle boat and I am told there is quite a lot of water in the Netherlands.

I will report the results of further tests.

Regards Tony.