Fremantle Sea Rescue is assisting a 34ft vessel moored off Rottnest's Thompsons Bay after its exhaust system failed and began taking on water.
The sinking vessel had two adults and three children on board.
Fremantle Sea Rescue sents its vessel R100 to the scene and the volunteers are now helping the boat's owner right the ship with pumps
#UPDATE: 34ft boat w/2 adults, 3 children on board located. Pumps were placed on board and the persons on transferred to R100. #perthnews pic.twitter.com/DKBziUsO04— Fremantle Sea Rescue (@FreoSeaRescue) September 27, 2016
Those on board were transferred to the R100 and placed on a ferry back to the mainland.
A spokesman for Fremantle Sea Rescue said the boat will be towed back to the mainland on Tuesday night, but that will be a long and slow process due to heavy seas and winds of up to 40 knots lashing the Rottnest channel.
