Looks like they were meant to have carriage bolts. The 8 sided star shaped holes would lock in the square portion of the carriage bolt nicely. All holes having the same punch instead of round hole is sometimes just bc it was cheaper to bang out at the factory that way. So my best guess is some sort of Chinese biminy/blind/rod holder brackets.
Those are rod holders. They're for securing fishing rods while trolling or to keep them out of the way. Their offset placement helps with balance and prevents lines from tangling.
Had to take another look see.....pole holders were probably right, my first thought when I saw the pic was they were on the bottom of the hull, not the side ! Guess at my age, I can declare a " senior moment".....best excuse I can come up with !!
Google Translate.........
The photo your friend took looks like a mooring bollard, used for tying ropes. However, the design is quite unique. The star-shaped holes appear to be designed to reduce weight or allow for attaching specialized accessories. I suggest taking more photos; you might find more clues!
