Currently (as of January 2012) there are no state or federal laws that require a boat owner to have insurance on a boat. The state of Massachusetts does not require insurance on a boat before registering. It is entirely up to the boat owner whether or not the boat is insured. However, if you have a loan using the boat as collateral the bank will require insurance coverage listing them as a loss payee to cover their interest in your boat. Some states may require that you carry liability coverage, so please check with your local law agencies to see if your state has any requirements. Also, most marinas will require that you maintain boat insurance in order to keep your boat at their facility.