When you do something that involves multiple steps, it's easy to forget one or two of them, and sometimes missing even a simple thing can have major implications.
Checklists counteract our forgetfulness.
Many professionals, such as airline pilots, use checklists several times each flight. Airline pilot Brian Koda, who also flies military aircraft as a Naval Reservist, says there are no fewer than six checklists that pilots use just to get the airplane from the gate to the runway. Some checklists, he said, are "written in blood," which means they were developed after a catastrophe to prevent it from happening again. Surgeons also use checklists to make sure they don't forget something critical in the operating room. Checklists for boaters can include mundane predeparture routines to those that help you in an emergency, such as what to do if your boat is sinking.
To make them more useful, checklists should be more than just a few things jotted on a scrap of paper. You'll want to first focus on the essential stuff that is frequently overlooked or skipped that may potentially sink your boat or endanger your crew. Next, what can damage your engine or electrical system? Finally, include a couple of small things that tend to slip through the cracks (see samples below). Checklists should ideally have no more than 10 items and should be able to accomplish in 1 to 2 minutes or they may start to feel like a distraction, which is when people often start "shortcutting," thus reducing their effectiveness. As the pilot told us, you can't spell out every single detail; a checklist cannot fly a plane. If you need more items, just make a separate checklist. For example, if your "leaving the boat" checklist is too long, make one for "locking up the boat" and another for "returning to the dock."
You'll want to use your checklist, test it, and refine it a few times as needed. If something changes on your boat, like you add a washdown pump that you want to remember to switch off at the panel, add it, though you may need to combine it with other similar tasks so the list doesn't get too long. In this case, you can add turning off the washdown pump to, say, turn off the cabin lights. For most uses, checklists should be a simple, one-page document printed in an easy-to-read font and a place to clearly check off each item.