Tuesday, April 7, 2015

Ordered Parts for Second Robot Quadmaran-5 / Similitude of boat models

Ordered parts for second Quadmaran-5

We raised enough money already from our Indigogo crowdfunding campaign to order the parts to make the second Quadmaran-5 robot so I did so today.  They will come by boat so 2 to 4 weeks probably.

I can't wait to be able to have two of these motoring around in train formation.

Models and Similitude

People should know that boat models show you what a larger boat would do in waves.   All you have to do is shoot a video and then slow it down by the square root of the scaling factor.  Our Quadmaran-5 is 1:16 scale model for a Quadmaran-80.   So if we slow the video of the Quadmaran-5 down by a factor of 4 we can see what a Quadmaran-80 would look like in waves 16 times larger than in the test.    This is called Similitude.   Most people use expensive wave tanks to test out engineering models of boats.   We are using real waves.  

Our approach is much cheaper.  However, we don't get to turn a dial on a machine to pick the wave heights we want.   In Anguilla getting an interesting size wave is not too much trouble because we have many different harbors with different size waves on different days.   The biggest trouble with our approach is that the winds are usually far too strong for the scale we are at.   Inside a building with a wave tank they don't have any wind issue.

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