How to Keep a Captain's Log

How to Keep a Captain's Log | Life of Sailing

Last Updated by

Daniel Wade

June 15, 2022

Keeping a captain's log is a good habit that can help you navigate and keep track of maintenance.

Generally speaking, there's no law that requires you to keep a captain's log. That said, keeping a captain's log can help you run a tight ship. The captain's log is used to record incidents, plans, and things that need repair around the boat.


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What is a Captain's Log?

A captain's log, or a ship's log, is a booklet or document used to record information about the vessel, navigation, and virtually anything else related to boating. Information such as sailing plans, GPS coordinates, ship sightings, and weather are often recorded in the captain's log.

Commercial and navy captains have been required to keep logs for decades, so the practice is nothing new in the maritime world. A captain's log is usually a medium-sized bound book or a binder. They're often labeled as such and sold at most marine stores. Today, many sailboat owners keep digital captain's logs.

Digital vs. Paper Captain's Log

What's the difference between a digital and a paper captain's log, and why choose one or the other? A paper (traditional) captain's log is a book, binder, or notebook that you keep aboard. Some of these logbooks are waterproof, making them a resilient and reliable way to store information aboard a sailboat.

Digital captain's logs rely on computers, which can be unreliable at sea for obvious reasons. That said, cloud-based storage makes digital logs almost impossible to lose. Additionally, a digital log allows friends and family to keep up with your whereabouts, which can be lifesaving in the event of a problem or emergency.

One way to bridge the gap between analog and digital is to keep a paper captain's log aboard and to upload a picture of the page each day. This serves as a digital backup with a timestamp and helps keep loved ones (and the coast guard) in the know in the event of an emergency.

Benefits of Keeping a Captain's Log

There's a multitude of reasons why you can benefit from keeping a captain's log. The most obvious benefit is that it helps you keep track of what's going on aboard your boat. If you notice a blown fuse or a loose cabinet, make a note in the log so you'll remember to fix it next time you're in port.

Another benefit is navigation, as the log is a central and organized place to record your location at various intervals during the voyage. You can also use the log to make calculations for navigating and refer to it for dead reckoning if your G13 should fail.

The captain's log is more than just a nautical to-do list. On a lighter note, you can use the captain's log as a voyage diary to record interesting events, information about people you meet, preferred passages and marinas, and more. It's a useful habit with both practical and fun applications.

The additional benefit of the captain's log is for insurance and resale. If there's an accident, recording detailed information in the ship's log can make the claims process easier. On the other hand, recording regular maintenance and information about repairs can help you fetch a higher price on resale.

What to Record in the Captain's Log

Given the limited space in the captain's log, it's important to prioritize what information you record. When keeping a captain's log, you should first prioritize navigation and maintenance.

Record information such as when you leave the marina, your destination, and expected arrival time. Other information such as known hazards, stopping points, drawbridge call signs, and weather forecasts are also helpful.

If anything breaks during your trip (such as a frayed halyard or an interior component), record that information as well. If you notice anything that will need repairs, such as a binding winch or loose helm pedestal, record it and use the log to remind yourself to have it repaired.

The captain's log is also the best place to keep track of your provisions. Before embarking on a voyage, take an inventory of your food, water, and medical supplies. Take daily inventories during your voyage as well.

This will help you stay in the know, and it'll prevent you from overstocking or running out of supplies. Don't forget to take inventory of items such as soap, toilet paper, toothpaste, and commonly-used spare parts.

Do You Need a Captain's Log if You Use a GPS?

These days, it's easy to dismiss the captain's log as an obsolete relic of a more tedious and imprecise era of marine navigation. However, even though it's possible to navigate without a captain's log, it's still a very good idea to dedicate a few minutes each day to record your position.

The captain's log is a great way to estimate your position if your GPS fails. Make a habit of marking your location on a physical chart every hour or so, and do the same in the log. That way, you'll always know where you are within about an hour.

With that information, you can estimate your future position by factoring in your course and speed. Plus, you can relay accurate information to the Coast Guard should an emergency arise.

Where to Buy a Captain's Log

It's easy to find a captain's or ship's log if you know the right places to look. The first places to try are local marine stores. Many medium and large-sized marinas stock items such as life jackets, flares, fire extinguishers, and logbooks. If you can't find a logbook at a local store, then try a major retailer such as West Marine.

Sometimes, even the largest brick-and-mortar retailer won't have a logbook. More often, they won't have the exact format that you prefer. For items like specialized logbooks, personalized logbooks, and binder refills, it's best to search online. Amazon has a wide selection of logbooks, though higher-quality products can be found through smaller specialized marine retailers.

Tips for Choosing a Captain's Log

For many people, it has been years (or decades) since they last took notes regularly. This can make it difficult to figure out what logbook format works best.

Think back to when you were in school. How did you take notes? Did you use a planner? If you're the neat, organized, and regimented type, you may prefer a classic blank logbook that you can format as you please. If you take messier notes, then you could benefit from a pre-formatted logbook, which makes it easier to stay clear and organized.

Captain's logbooks are available in all shapes, sizes, and finishes. You may want to consider a water and weatherproof logbook in rougher climates. If you have a large and dry boat, you can use a fine leather-bound book with more confidence.

If you use a waterproof logbook, be sure to pick a pen that won't wash off or smudge on the page. Also, remember that ballpoint pen ink fades over time, especially when exposed to sunlight. If you don't want to buy a special pen, a thin permanent marker will usually suffice.

Tips for Filling Out a Captain's Log

Filling out a captain's log is easy once you decide how to organize it. There are a few widely-used methods to filling out a captain's log, and which is best depends on how much information you want to record.

Sailors who like to record lots of precise navigational information usually utilize the back of the previous page for a table. Often, they'll create a table with hours on the 1-axis and information about position, speed, and weather on the X-axis. This way, a quick glance at a few instruments every hour leads to a complete technical record of the entire voyage.

Since the chart occupies the back of the previous page, you can reference other voyage information from that day without turning the page. On the other page, you can record information such as incidents, anomalies, things that need repair, and other general notes.

If you decide to use a single page, you can use the top section for technical data (course, speed, weather) and the bottom for destination information and other general notes.

The primary purpose of the captain's log is to help you run an organized and safe boat. Therefore, you can develop a system that works best for you. That said, it helps to be consistent with the layout in case you (or someone else) need to go back and find information about a specific part of a voyage.

Alternatives to a Captain's Log

A full captain's log is probably overkill for certain voyages. For example, if you only make short day trips in a closed lake, you may not need to mark your position or speed. In these situations, you may consider downloading a captain's log app for your smartphone.

Combined with a waterproof case, a captain's log can make it easy to keep up on maintenance. Captain's log apps are also useful for bluewater sailing, as long as they're used in conjunction with a log that doesn't require electricity or internet connection to work.

Many sailors know that power and connectivity are fragile systems, so it's always good to have an old-fashioned pen-and-paper backup.

How to Keep a Captain's Log
Daniel Wade

Daniel Wade

I've personally had thousands of questions about sailing and sailboats over the years. As I learn and experience sailing, and the community, I share the answers that work and make sense to me, here on Life of Sailing.

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