Perched on the southeast corner of the University of Washington campus, where the Montlake Cut meets Union Bay, the ASUW Shell House looks as vulnerable as it does majestic. Over the course of a century, the structure built as a critical wartime post later was the home to a group of rowers who captured the nation’s imagination before becoming an all-but-forgotten artifact of the past. Now, propelled by a wave of renewed interest, the 12,000-square-foot wooden structure is the focus of an $18.5 million campaign that will restore and renovate the space.