Floatdown evaluation is the most comprehensive and detailed type of inspection. A "hands on" type of inspection allowing the inspector a close-up view. The inspector installs a sterilized rubber raft inside the tower and inspects every surface of the tower as the tower is drained. The inspector is then able to test coating failures and blisters to determine the extent of underlying damage. These DTF readings will be added to the report. This method gives the inspector a true picture of the extent of metal loss to determine the amount of welding and grinding needed. The close-up photos taken of all areas of the tower are very important. The tower will then be cleaned after the inspection.