Volume of a section of a shelled model.

I am trying to find the volume of the shell's portion in 1 segment of the canoe. I have 2 questions: 1. Does the volume option in Mass properties determine the volume of the model as if the model was filled with a fluid (in other words, is the volume found here the total volume as if the model is not hollowed?). 2. How can I find the volume of the shell? I tried doing Volume filled - Volume with shell, but the answer does not make sense as the volume of the shell. I also tried with the intersect tool's internal regions but no internal regions can be produced in my model, I assume because it is already shelled.

Thanks.


Edu ​​​​​​​