There are no restrictions for private vessels wanting to enter the Hervey Bay Marine Park for the purpose of whale watching, but a number of factors must be taken into consideration:
Hervey Bay is a large stretch of water and the whales could be 20 or more miles out. Is your craft seaworthy, equipped with all safety gear, extra fuel, if required? Can you handle your vessel in adverse conditions and can your passengers?
You will travel very low to the surface of the water and will have difficulty seeing the whales. Do you know the Regulations of the Marine Park? Can you judge and maintain the required distances to avoid interference with the whales natural behaviour?
Can you guarantee, that you do not harass whales, not even accidentally?
The tours are all "affordable". You may find that it is cheaper to travel on a commercial vessel than with your own.
Being amongst a group of enthusiastic whale watchers is a real "buzz", where you will share your experiences, meet new friends, to be able to have a drink and do not have to carry any responsibility. You can expect better viewing and have the benefit of an entertaining, yet educational program about the Marine Park and its animals. And perhaps listen to the whales singing?