I am doing some research into the use of weather vanes under water. This "water vane" would serve the same function as a weather vane does in air, just while submerged in water.
I understand that weather vanes must allow for free movement around a vertical axis.
I read here:
The surface area of the design must be asymmetrical, unequal, which enables the smaller area to turn into the wind. However, the weight must be equally distributed on both sides of the axis of rotation to allow the wind vane to spin freely.
This makes sense in air, however, my question is, when constructing a "water vane", do the same design principles change? By design principles, I mean, need the tail be larger than the head? Must mass be evenly distributed between the head and tail for free movement?
I ask because in a medium like water, buoyancy forces at play would support the vane. This is not the case in a medium like air. Would the extra support of buoyancy allow the vane to rotate differently? I could not find any literature in the way of water vanes.