Not true, otherwise scale model testing of large ships would not work. The reason scale models are used in tow test tanks is because the effects can be corrected by using the Reynolds Numbers to adjust the effects.
So you'd have to use something other than water, with a very different Reynolds number (I wonder what you'd have to use to simulate something that small?) which means that again our intuition about what would happen in water is irrelevant.
Also as you point out that's used for tow tests. No-one tries to simulate the actual mechanism of propulsion, which would be more difficult. The non-scaling relationships between length and area and volume and mass would get you every time. But even if it could be done, then, as I say, our intuition, based on water, doesn't tell us how the experiment should turn out. There's no use for common sense applied to conditions with which we are unfamiliar.
Personally, I pay very little attention to FFA topics, as I view them as dump sites for misc. material of dubious value (or something like that).
I'm now guessing that much has happened in this topic that should have been in more theme specific topics in the "non-garbage dump" forums. Thus, I'm going to close this one down and force those good themes to find a better home. At those better homes, feel free to link back to this topic - But the relevant text should be included in the "better home".
Closing in no less than 15 minutes.
Gripes about this action? Consult "Index to certain important topics" to find the appropriate place to gripe.