Sunken Concrete Pontoon

In July we dove a new target; one I am not sure anyone has dove before.  It is a huge concrete structure at the south end of Lake Washington – we came across this structure while doing some side scan sonar work in the area.  It is approximately 200 feet long and maybe just 20 feet wide.  In all it took us about 35 minutes to swim around the entire thing.  It appears to have massive holds inside; leading us to believe this space was used for ballast and this structure is either an old floating pier or it was at one time a section of the original floating I-90 bridge.