This is taken from the GIO PDS
Proof of seaworthiness
When you apply for this insurance or before renewal of your policy we may ask you to supply us with proof of seaworthiness and good condition before accepting your application or offering renewal.
This depends on your boat's:
type and model
age
construction materials
motor type (eg. in-board petrol)
modifications
location when not in use (eg. moored).
What is proof of seaworthiness?
Proof of seaworthiness means
a written report by a marine surveyor or another qualified expert certifying your boat to be seaworthy and in good condition, following a physical inspection.We will tell you if the inspection needs to be done while your boat is in the water or out of the water.
The report needs to include checks on all aspects of the boat's operation such as the hull, electrical components, motors, structure and safety gear. The report must be less than 12 months old and you must pay for this report.
www.gio.com.au/documents/car-and-vehicle/boat/historic/gio-boat-insurance-pds-17-09-2010.pdfIf a surveyor is doing it then he's probably going to charge the same regardless of what the heading on the paper says it is, wether it is a certificate of seaworthiness or a survey. The highlighted text put in by me.
From the point of insurance it appears a certificate of seaworthiness is the same as a survey.