There are three kinds of waves:
Where the beach is relatively steep waves can break with considerable force. It can be dangerous to swim in these waves. They are a common cause of broken limbs and back injuries, take care!
The crest of a spilling wave tumbles down the front. If the sandbank where it breaks is shallow, the spilling crest will form a 'tube'. These are the best waves for body surfing.
These never break, because the water beneath them is deep, but they can knock people off their feet and drag them back out.
A rip is a strong current running out to sea. Rips are the cause of most rescues performed at beaches.
A rip usually occurs when a channel forms between the shore and a sandbar, and large waves have built up water which then returns to sea, causing a drag effect.
The larger the surf, the stronger the rip. Rips are dangerous as they can carry a weak or tired swimmer out into deep water.