In order to correctly model submerged weight it is necessary to switch on the wave loading module. Even when the wave theory is not specified and the wave height is zero the structure is being massivley laterally displaced when I turn the wave load on.

Is there any way round this? I have tried with a few different wave theories with similar results. The wave velocities are shown in the output as zero, but the structure is being massivley displaced when the wave module is on.

I have tried a frictionless case so there should be no difference between displacements for the submerged/dry weights but a difference is occuring...

Buoyancy is tied to the "load primative" WAV1, WAV2, WAV3, WAV4 - you have to have one of these in your load cases to get buoyancy.

If you have no wave or current, and you want buoyancy, define an "Airy Wave", with a wave height of 0.1 ft, a period of say 20 seconds, and the correct water depth. This won't put any wave loads on the sytem, but you'll get buoyancy.

If you still get your "massive lateral" displacements, something else is wrong. What happens if you push (in the same direction) on the model with a 100 lb load?