Hi Ed,

Thank you for your detailed reply.
I had an application that needed to read the thrust of a jet of water and before our order of force sensors came in we used a paddle wheel to determine the speed of the jet.
The results were within 5% of the real sensors readings.
Depending on your precision and accuracy requirements any of the suggested methods should work but with some penalties.
IMHO your biggest problem will be the changes in water density due to various reasons (salt, temperature…..)

Thank you again and good luck.

Regards,

Nick