The aim of training on manned models is to enable seamen to acquire or to develop manoeuvring skills through a better understanding of a ship's behaviour as it sails in restricted water conditions at manoeuvring speed. Manned models are considered by ships' captains and maritime pilots as the next best thing to a full-scale prototype for understanding a ship's behaviour. Training on the scale models provides experience that could never be gained on real ships for the simple reason that neither ship-owners nor local authorities would allow such risks to be taken. Scale models allow the shiphandler to make mistakes. Scale models allow experimentation on ship behaviour to explore unknown fields beyond the limits of safety.