After seeing an unknown image during a recent sidescan effort our team decided to dive on it an see what it might be.
Surface conditions were spectacular but as it turns out that was not the case on the bottom. Ben Griner, Shaun Gardner, and Bob Bailey dropped to 205' which is about as deep as you can go in Lake Washington. Shaun was in position one and responsible for the reel work. Upon reaching the bottom we had visibility of less the 5 inches. Using touch signaling Shaun indicated he wanted to try a search. We began a circular search pattern hoping that the visibility next to line was poor due to the line shot hitting the bottom. Unfortunately that was not the case. The searching was slow and we maintained touch contact with both the line and the divers beside us. After 10" we decided to call the dive early. Using a bump-n-go advance down our search line we headed back to the drop line. On the way back we realized our line had wrapped around something. Bob freed our line and Shaun and Ben explored the boat by touch. Bob hovered directly over Shaun and Ben so that no one accidentally swam under something. After another 5 minutes of exploration we left and again started heading back just to realize that the up-line was not more than four feet from the small boat.
After hitting the line we settled in for a long and cold deco. Scott Christopher acted as the safety diver for this dive and met us at 70'. Scott completed deco with us and once hitting the surface Marc Greenway quickly picked us up.
After a little research we determined the small boat was indeed a boom boat. Click the link below to see a video of a similar looking boom boat in action. At this time we do not have any plans to revisit this site. But may explore some of the debris around it when visibility improves in the spring.