I made vibration dampeners for the inside and outside of the boltholes. The top of the transom has a board running through it to stiffen it. Under the seats, however, is just hull. I added a 1x4 down there to distribute the forces and vibrations. The engine mount went on the side of the transom where I had previously painted the name of the boat. I scraped that off and had to paint it on the other side of the transom.