noun - IRB or Inflatable Rescue Boats are rubber boats with an outboard motor used in surf lifesaving. IRBs have been used for all forms of surf rescue, retrieval, and service by Surf Lifesaving in New Zealand, Australia and elsewhere since the late 1980's.
IRB's are made of rubber and consist of four inflatable tubes - two side tubes, a bow tube and a keelson tube. This specific feature coupled with the obvious fact that they are used in the water, has coined the term "rubber duck" or simply "duck" to describe an IRB.
IRB's are of great value when patrolling a beach especially ocean surf beaches where either the surf is too powerful or the beach too large to perform rescues effectively on a board.