US Navy uses 40,000 pound explosive to test warship in 'Full Ship Shock Trial'. The United States Navy has been carrying out 'Full Ship Shock Trials' off the country's east coast. This is to ensure their vessels can withstand battle conditions. After the completion of the trials, the USS Gerald R Ford is due to undergo ‘modernisation, maintenance and repair’. The US Geological Survey registered the explosion as a 3.9 magnitude earthquake.