A sea trial or trial trip is the testing phase of a watercraft (including boats, ships, and submarines). It is also referred to as a shakedown cruise.That is the way it works. Here we will discuss the brief nature of both , what all procedures are carried out during shop trials and sea trials. Sea trials test ship speed and machinery in open water. Test bed tests check machinery in a test facility. A sea trial is the marine equivalent of a test drive, crucial for assessing a vessel's performance before it is fully commissioned or sold. Shopping for a 32 CB and out on a sea trial. The best cruising speed I can get out her is 16 knots at 35gph. Its the beam and the bridge wings.