Water_displaced_mass calculation.

[JordanGleesonQUT]

I am increasing the scale of the rudderboat to 1 so that it is about 5m in length to suit our purposes. Everything is working so far however I cannot seem to be able to find the right value for the buoyancy. How did you calculate the values for back_water_displaced_mass, middle_water_displaced_mass and front_water_displaced_mass.

Anything I calculate makes the boat bounce around wildly, and if I reduce it the boat just sinks, I can't seem to find that happy middle ground.

[JordanGleesonQUT]

I tried to numerically find the mass values by bringing the models into Blender to determine the volume below water level. The values I found are:
back_water_displaced_mass = 356
middle_water_displaced_mass = 427
front_water_displaced_mass = 226
However the boat still bounces around wildly.