This clip is quite long and unedited:

The thrust has been increased to 1.5N.  The speed limits at 5kph.  I expected more but I did not analyse the wave formation until I observed what was limiting speed.

There are two speed limiting factors that are due to the wave making of the hull.  At 5kph the peak wave height is  15mm.  The wave trough is midship and that causes air to bleed out of the cavities with the cavities less than half full of air.  The static draft is only 15mm.  That increases the wetted surface on the bottom and sides in both cavities but more in the aft cavity.  Also I have a small block of foam that is only partially faired inside the aft cavity at the stern.  This is creating a lot of turbulence in the back of the cavity and entraining air.  When the model is close to the camera approaching the shore you can see air bubbles coming out of the rooster tail.  

I would need to make more cavities to overcome this in the existing model.  However it was not designed for low wave making so not much point. I plan to do some trials on one of the pedal boats next.  My side-mounted prop might suffer some ventilation due to proximity of the cavity but that is more likely when accelerating as the prop is more heavily loaded.   

Rick

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