I suppose context would be helpful.
The holes are on the starboard side, almost all the way forward where the aluminum flooring ends and the wooden bow insert is. A previous owner added hold-downs and battery-strap mounts in the midsection and rear. My first guess would have been for a seat, but the distance between the holes seems to not match with seats.
Related question - how can I figure out what size bolts would fit in the holes?