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[sswcharlie]

Hi
 
What is the best method to check for thrust of a small boat. Using a trolling motor.
Can I use a weigh scale like used for checking travelling bag weights, and place boat in a tank etc attached to the scale.
Want to measure changes of thrust with variable speed and different propellers.
 
Thanks
Charlie

[Shipmate60]

Push against a set of kitchen scales.
if the scales are too high just tape a piece of dowel  on the superstructure.


Bob

[malcolmfrary]

The bollard pull method will give sufficiently consistent results as long as all measurements are taken in the same tank to tell the difference between combinations.  It should be remembered that results may change when the boat is released, and is allowed to move through the water, rather than just move water in an enclosed environment.  Its the difference between theory and practice.
Welcome to ModelBoatMayhem.

[derekwarner]

  ...a simple set of fish scales is the simplest & most accurate method of confirming a model vessel 's thrust........... ........Derek

[sparkey]

  I agree I used a set of fish scales in the bath one end fixed to the taps and other to the boat,this gave me an idea what size of prop to use,the down side is that this can be messy(on full power which can upset the wife) and only gives you an idea,the best way I think is testing at the lake after all a bath is not the lake.I have been lucky in that I have found someone with the same model and copied their setup and tried to improve it,this forum is a good place to start you are bound to find someone with the same model and work from there,I hope I have been of some help,happy sailing,Ray.