The best way to let someone know you are leaving on an excursion with a boat is: by filing a boat plan.
A boat plan is also referred to as a sail plan or float plan and it can be defined as a paper document that outlines a traveler's itinerary and other important information while on water.
Generally, a boat plan comprises the following important information about traveler and the trip:
Ideally, it is a good idea to ensure that you inform a friend or family before taking your boat out for an excursion. Also, the best way to accomplish this is to file a boat plan.
Read more on here: https://brainly.com/question/10339634