Self-righting system when capsizing

I have searched some ships which have self-righting capablity.

1. boat(less than 10meter) : most of them are equipped with orange color's self-righting bag.

2. more than 10 meter : I can't understand how to be stable position when capsize.

today I read some news report below.

http://www.maritime-executive.com/article/Boat-Like-a-SelfRighting-Bath-Toy-2014-02-05

air bubble in the wheelhouse which enables the capsized ship to right itself quickly

I want to know exactly how to make air bubble from wheel house.

are there guyz who know this principal?

 

The air in the wheelhouse is enclosed if the boat is capsized (upside down), because the wheelhouse stays watertight even if immersed.

So the wheelhouse works as an "air bubble" and provides a lot of bouyancy.