This involves a coach or specially trained person warning a swimmer when they are close to the edge of the pool or when they need to turn by tapping them with a long foam-ended pole.
However, if a signal is given too early or late, it can lead to a swimmer being disqualified or injured.
Final year product design student, Mirthe Hofstede has designed Optic – a navigation aid for visually impaired swimmers that allows them to navigate in the pool efficiently and safely.