Slanted hull front edges
The front edges of the hull sides are slanted forwards. The hole for the towing shackle is halfway up the straight edge. The top corner may be notched or rounded.
Vertical hull front edges
The hull front edges are close to vertical. The hole for the towing shackle is near the bottom of the straight edge.
Notched hull front edges
The overall shape is the same as the vertical front edge, but a large notch is cut in the straight portion.