Check & recheck. A) Karen Johnston (Marine Laboratory Specialist, IODP-USIO) ensures the shackles are secure as she readies the GI gun for deployment. B) Mike Meiring (Marine Instrumentation Specialist, IODP-USIO) and Roy Davis (Lab Officer, IODP-USIO) guide the airlines and cables overboard as the GI gun is hoisted into the air. C) Positioned approximately two meters below sea level, the gun is used for vertical seismic profiling. (IODP) [Photo ID: exp308_050] Back to expedition photos.