looks like the only way water can get up and in there in either from spillage of the front bow sac and rolls forward , the bilge water running up from the stern to the bow thru the ski locker drain hole during start and stops or some poor seal around the floor in the bow from some rollers. since the deep v under the ski locker is the lowest point in the boat it will be hard to get rid of that water by normal draining... my .02

not sure why that part in not sealed as it looks like the locker is added to the stringers afterwards in the pic # 1


sc any time would be great to chime in.