There is a web site,
boatequity.com.au/You could also put up notices around the local clubs.
Your first issue to solve though would be where to keep the boat, as pens on the river are hard to come by.
Also be aware that if the boat does not have mast lowering capacity it costs around $10K.
You might be better finding a near new boat in Perth than a new one. Best place to start is to join your local yacht club, you will be supprised how helpful some are.