What do you want to find out exactly?
If you choose the option in the simulation options to save temporary files and then run your analysis, you can go into the .out file and it will tell you things like the mass of the assembly and moments of inertia...etc. Is that what you're looking for?
I have a large surface model of a ship.
In Simulation I have applied the shell thickenesses to the surfaces.
I want to extract the resulting I values of the sturcture at particular sections through the ship.
You're going to have to do a quick thicken on those parts and use SolidWorks to do that. I can't think of any way to do that in Simulation either from the interface or the out file. There is no reason that I can think of for the software to know that information for the calculations that it needs to do.
What you could do is check what happens if you do a 2D simulation. the .out file might have information about the section's I. this would be a bit tedious.
Is there a way that you could get the I through a simple simulation test?
It sounds like a good enhancement though, the data is there, it would be a good back check. I just don't know how many people need it. Do you have a reseller that you can connect with to look into this further and check with SolidWorks technical support/the development team?