If you keep your boat at a marina then yes most if not all marinas will require you to have liability boat insurance on the boat to use it in the water.
You also need a boating license and get the boat registered with the marina.
If you just take the boat out to a private lake or a lake way off where no police are or game wardens are then you'll likely be able to get by without any boat insurance or a registered boat or even a boat license.