Hello I am looking to model buoyancy, is there a way to stop an object falling over only buoyancy straight up and down

Hello,
I am trying to model a buoyant house simulation- However am having problems keeping the buoyancy in one plane. This is what the pontoon posts are for in real life. If anyone could please help me simulate this that would be great- thank you

https://drive.google.com/file/d/1KIIGwubTON0ZTzp4-RmG5sE0V_yiC_-F/view?usp=sharing