Summary

This design is in response too - Benchy

I mean if you print something you would expect it to be functional. I made the mistake of printing it for my kids, only for it to float upside down in the bath.

Well Benchy - meet the Sydney Ferry CAT

Bath test
At least it floats up right, next is to make it higher in the water line

fail v2 has window detail pulled out
fail - v4 bigger hull & window area removed, and a larger level one - displacement

v5 Build a air box in the base of the lower deck with a hole for the material to wash out - leaving a hollow