IOWA CITY, Iowa—A woman whose family went on an Iowa amusement ride shortly before an accident that killed an 11-year-old boy and critically injured his brother said Friday her boat also had problems floating properly and felt unsafe. Amber Estrada, 31, said the boat carrying her and her husband, their three children and nephew at times struck and dragged along the bottom of the manmade river on the Raging River ride at Adventureland Park in Altoona on July 3. She said the boat made a grinding sound that she could feel under her feet. Estrada, of Eagle Grove, Iowa, said her husband told her that he felt scared and wanted to get off the ride. The couple made the decision to lean forward in their seats with their children because they were worried it would tip over, she said. They were able to reach the end of the ride safely, …