On the morning of April 18 , 1988 , the oil platforms were knocked out turning the operation to a search for reported frigates in the Strait of Hormuz , a body of water between the Gulf of Oman and the Persian Gulf .
On the morning of April 18 , 1988 , the oil platforms were knocked out . 
 The U.S. forces then turned to look for Iranian frigates in the Strait of Hormuz , which joins the Gulf of Oman and the Persian Gulf .