Basically my question is the subject.
SO if you have a large pan the same shape as the boat as filled with water and you put the boat in the pan - how much water must the pan have for the boat to float ?
Say the boat weighs M kg.
Displacement, AFAIK, doesn’t concern itself with mass, but with volume. A boat needs to displace its volume in water to be able to float. I’m sure that somebody else will come and provide a better answer.
Depends on the underwater surface area of the boat, and the smoothness of the boat and the pan.
If you assume perfect smoothness, then almost no water is required - just enough to form a layer a few molecules thick over the surface area.
And BTW, there’s another thread currently on the front page that also deals with this topic: How exactly does a boat float?
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And for that reason, I’ll close this one and address questioners (and answerers) to the other thread.