Thank you JapLance !
Assuming that these devices are from WWII and dimensions are in millimeters...
Here is a comparison of VonDos' paravane with all 4 types :
And a comparison with the type B :
So the lenght is correct, but the diameter is too massive. And the shape can be improved too.
Here is the Wings3D file :
https://www.mediafire.com/file/65g1j...NES.wings/file