How piston cooling is done in main engine?

Here, I have explained piston cooling of main engine(Sulzer engine). The working piston consists basically of:

1. Piston skirt is directly screw fastened to the piston rod.
2. Piston crown and piston rod are joined by ten elastic bolts 9(indicated by 1 in the figure).
3. The oil cooling components and piston rings (indicated by 2 in the figure).
4. Piston rod (indicated by 5 in the figure)
5. Piston crown (indicated by 1 in the figure)
6. Piston skirt (indicated by 3 in the figure)
7. Piston rod is fastened to crosshead pin (indicated by 1 in the figure) in a particular position.
8. A compression shim is fitted between them (piston rod base and crosshead pin), its thickness being adapted to the compression ratio.

Fig.: Piston cooling of Sulzer engine