The Hilma Hooker is a 235-foot long steel boat that was purposely sunk in the double reef system in September 1984. The sequence of photos to the left shows the sinking. A link to the source of these photos, along with the somewhat sordid final history of the Hilma Hooker can be found here. The source of the above graphic is here.
In the photos below, Linda is at a depth of about 50 feet while the sandy bottom on which Hilma lies is about 100 feet.