Thanks for your comments,
@dirvin21 single kayak is my next step, as my wife, is always concerned about my safety, she tags along all the time when I go fishing.... That's why I said "Tandem". And I have a Corolla hatchback, over the top of my head, I need to equip cross bars to carry a large kayak. I heard it's not safe to drive on motorways, not to mention the length of my car. Ocean kayak would be the final option if I don't need to feed the family..... I will think about sit-on kayaks, this is important to me, safety always comes first.
@savit "Easy to carry" and "Easy to clean" would be wonderful for me. If I go somewhere, say, Blue Mountains or small lakes, central coast, or botany bays, I just drive my car to get there, and put together pieces, then have fun. I will try big snake and C-kayak