What is this hole for??

[wreckingball]

so i took off some "homemade" covers and found these hole total is 4 of them and was wondering what they are for ?? all located at the back of the boat

 

[ajgraz]

How big are they? Maybe someone added access holes, for getting to wiring, bilge hose, through-bolts, etc.

 

[poconojoe]

Drainage? Take another photo from further away so we have some reference.

 

[wreckingball]

about 3" across , i have them on both sides

 

[JimS123]

They are vents. One should be open and the other should be fitted with a hose leading to the bottom of the bilge.

 

[GA_Boater]

What boat? Google the boat and you might see some pictures showing what the holes are used for.