The problems which arise in the course of a study of aeroplane stability are of considerable complexity as compared with those confronting engineers in other branches of locomotion. Ocean–going vessels provide another instance of the motion of a solid body in a fluid and their stability is clearly one of vital importance. Naval architects have consequently studied the subject and calculations are made for the stability of each new design of ship. The process is so well known and so well founded that it surprises no one that a newly launched vessel remains on an even keel. One instance, not connected with British shipbuilding, serves to remind designers of the serious consequences of faulty calculation. The disaster relates to a ship which was launched fully engined, etc., and which turned turtle and sank within a few minutes of launching.

The type of stability which the naval architect needs to calculate most carefully is that which is concerned with the security of the ship when rolling.