If you've never experienced the tension of failed equipment aboard or had to explain to guests why there is no more fresh water or panicked when thick fog closed in just after you had forgotten to make note of the last two buoys, you probably don't need to keep a log. But for those more human, it's not a bad idea.
Developed and refined endlessly over three decades by longtime cruiser Dale Nouse, The International Marine Log Book is flexible enough to allow to record anything from bare piloting details to names and anecdotes that are valuable and/or enjoyable to recall. It will encourage good piloting, train you to be a careful observer of weather, stimulate you to run through a vital maintenance checklist, and serve as a compendium of interesting information about your boat.
The International Marine Log Book--complete, compact, and durable--will make all others obsolete. Here is a legal record of your boat's cruising history; vital navigational aid; concise and accurate weather-forecasting system; daily checklist of your boat's mechanical systems; permanent record of your boat's important data; journal of your happy times afloat.
Log keeping pages for 105 days of cruising formatted parallel to spine for easy use. Each day gets two-page spread featuring morning maintenance checklist, record of times, courses, distances, positions.