Fixed versus moving shock trials

A ship and an explosive charge can be fixed at known positions to produce controlled shock-trial data. A warship in combat will normally be moving, introducing a relatively small variation in the angle and effect of the shock. The controlled test supplies a reliable baseline, while an underway test adds the variation caused by motion. Both are useful, although shock testing deliberately stresses and can damage a new ship. Builders and governments face repair costs and commissioning delays, making fixed trials an economically attractive choice.