I just bought a 16' Crosby fiberglas project boat. It's not in too bad of shape. It looks to me like the floor has already been taken out. You can see outline of short stringers up the bow. The thing that has me puzzled is that there are three drain holes in the transom. One up high for the splash well and two at the bottom of the transom. One drains the floor area that is now bare and another one about two inches below that at the very bottom of the transom. Is there another floor below my bare floor. I don't think there's room for one but what is that other drain hole???