Our garage is 21'6" long. Our old boat (96 PS 190) was 21'4" long on the trailer w/o platform. From my experience with this, it was a nightmare. It was extremely difficult to get the boat into place and I had ductape on the floor to mark where each wheel had to be. I typically had to move it the last 3-5 feet by hand. This was difficult with a 2400 lb prostar on a 1000 lb trailer. If you have to do this with a 4000 lb star on a 1000 lb trailer I would say it will be extremely difficult. You probably have a tandem trailer too which will make turning next to impossible. My suggestion would be not to cut it close. Make sure you have sufficient room to move the boat with your tow rig and not by hand.