Larger boats will typically have a permanently fixed inboard motor. Usually these motors are diesel and are started with a switch and a key, similar to a vehicle. Any motor should have a kill switch which can allow you to immediately stop the motor if there is any type of emergency or someone is knocked overboard.
Boat trips are great for all age groups. You don't have to be a professional boater to enjoy the water. In fact you may even be able to leave it at the dock the whole time. If you want a new and interesting way to spend your time, consider renting a boat for this.