First-of-class trial

A first-of-class trial is the extended sea-trial program run on the lead ship of a series, more thorough than the repeat-ship trials because it validates the design against prediction for the first time. It carries the full speed/power matrix, the complete maneuvering set (turning circles, zig-zag, spiral, crash-stop), seakeeping and slamming observations, the vibration and noise survey, and any mission-specific tests, with results fed back to confirm the model-test predictions and the as-built lines. Sister ships then run an abbreviated acceptance trial against the first-of-class baseline. Naval and offshore programs treat the first-of-class trial as the design-acceptance event for the entire class.