A life vest (Personal Flotation Device) is mandatory on all boats for all passengers. (A pealess whistle attached to the PFD is an excellent idea!) You should wear one at all times. If you have children with you, they should wear one even when you are at the dock.
Every vessel, regardless of length is required to have a certain amount of safety gear aboard. This ranges from an anchor with sufficient rode, flares, and other equipment as may be mandated by the Government. These regulations are for your safety and should be adhered to.