Side scan imagery of Lake Washington – Debris complicates shipwreck exploration

Puget Sound Divers logged over 1000 hours of side scan searching on Lake Washington last year. These efforts resulted in the successful identification of several shipwrecks and the location of several planes resting on the bottom. However, as the team continues to refine its searches looking for smaller and smaller targets and targets that may be partially or mostly in the silt layer we increasingly have to determine what is a natural formation or trash vs. what is of historical significance.

Potential-logs.gifPotential Logs

In the picture above you will see that this appears to be an image to several logs. However, the object on the lower right side of the logs has an oval appearance and could easily be a small boat lying upside down in the mud. This would account for the poor shadow cast by the side scan unit.

This image is a slow scan pass at just 100 feet from the target with the side scan unit only 20’ off the lake bottom. These objects are located in 195’ of freshwater. To obtain these images took 2 hours of team time at a cost of approximately $300.00. Further exploration of this site is estimated to require divers to visually inspect the objects at a cost of over $750.00.

Currently our team has a long list of other small targets it has ranked as higher priority for its exploration efforts and at the rate we are able to obtain new targets it is likely that this site will not be dove for another year or more depending on funding. However, our team will continue to dive on these small targets as this is exactly how we discovered the boom boat sitting at 205’.