# Why do ship's captains keep logs? **URL:** \ **Category:** Factual Questions\ **Created:** [April 16, 2006, 11:44pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923 "2006-04-16T23:44:34Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [April 16, 2006, 11:44pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/1 "2006-04-16T23:44:34Z")
I can understand why Navy captains would keep logs – the military wants to keep meticulous records of everything. But in the film _Dead Calm_ – [http://www.imdb.com/title/tt0097162/](http://www.imdb.com/title/tt0097162/) – a man who is simply taking a sea vacation with his wife in his private yacht logs everything that happens, the ship’s location at every day, in highly technical nautical language – what use would such records be? (Some, perhaps, to investigators in the event of disaster or crime at sea, such as happens in the film – but who goes to sea expecting something like that?) And I infer such is standard practice for all masters of craft, admirals and yachtsmen and all in between. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [April 16, 2006, 11:52pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/2 "2006-04-16T23:52:15Z")
Yep. Standard practice, and for pretty much the reasons you surmise. Until fairly recently, the idea of a “pleasure cruise” was unheard-of, especially captaining your own boat. The log was necessary to let crew know exactly what happened while they were asleep, or otherwise occupied. It served as a record of disciplinary actions, weather conditions, crew morale, food conditions, etc. for anyone who came afetrwards, and acted as a reminder for the captain on later voyages. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [April 17, 2006, 12:17am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/3 "2006-04-17T00:17:52Z")
The detailed ships log was not widely used until 1850, when the Royal Navy made it mandatory: > [@](#): > > During the early part of the century there was little legislation affecting the lives and conditions of Merchant seamen. Their accommodation, hours of work and food were left entirely up to the ship owners that employed them which in effect meant that their Captains were left to do much as they pleased. Whatever food was supplied to the ships was given out as daily rations, this was often extremely basic and was no more than required to keep body and soul together. The conditions in which seafarers lived were no better and in some cases worse than those that prevailed during the Elizabethan era and passengers fared no better. Those passengers wealthy enough were expected to provide their own linen and furniture and steerage even their own food, only water and fuel was provided. In 1850 when it was thought conditions couldn’t get any worse and the viability of the Merchant Service was in doubt the Government after consultation with the Board of Trade introduced an act of Parliament entitled “ An act for Improving the Conditions of Masters, Mates and Seamen and Maintaining Discipline in the Merchant Service”. > > The principle feature of the Act was for the establishment of Shipping Offices in all the main ports were seamen were engaged and discharged from their respective ships, ships articles became the responsibility of the Shipping Master and it was his duty to read out to the seamen what was contained therein before they “signed on”. \*\*The official Ships Log Book came into being also, this book had to be presented to the Shipping Master on the vessel’s arrival in port. \*\* Attention was paid to the sleeping arrangements and a minimum space allowance of nine superficial feet was allocated to each seaman, a provision and supply of medicine also had to be available on all ships. Most importantly however was the introduction of an examining body, these examinations were initially to be conducted by local marine boards and all foreign going Masters and Mates had to hold the relevant certificate. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 17, 2006, 12:22am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/4 "2006-04-17T00:22:55Z")
> [@BrainGlutton](#): > > I can understand why Navy captains would keep logs – the military wants to keep meticulous records of everything. But in the film _Dead Calm_ – [http://www.imdb.com/title/tt0097162/](http://www.imdb.com/title/tt0097162/) – a man who is simply taking a sea vacation with his wife in his private yacht logs everything that happens, the ship’s location at every day, in highly technical nautical language – what use would such records be? (Some, perhaps, to investigators in the event of disaster or crime at sea, such as happens in the film – but who goes to sea expecting something like that?) And I infer such is standard practice for all masters of craft, admirals and yachtsmen and all in between. I don’t remember the entries in the film, but they were probably expanded for narrative effect. Some may use it as a Dear Diary as well, but the ship’s logs I’ve seen tend to eschew information on the skipper’s emotional state or the selection of dinner items. That being said, a good skipper should maintain time, distance, and location logs so as to locate his vessel and stay clear of any navigational hazards and be aware of shipping lanes. He or she who neglects this (and there are plenty of them about) does so at own peril. It may seem quaint in these days with handheld GPS receivers, but even fifteen years ago, once you went over the horizon in the blue water the only things you have to guide you are your compass, the stars, ded reckoning, and the occasional pip of an atoll sticking up somewhere. Make a wrong calculation and you may end up thousands of miles off course, so maintaining accurate logs is important, and a GPS system is not an adequate substitute for this. (Old salts know that there are two kinds of marine electronics: those that have already failed, and those that are going to fail at the most inconvenient time in the near future.) Keeping detailed logs is also valuable for observing and integrated meteorological phenomenon to estimate the change of seasons, a not insigificant concern on the high seas. Stranger ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [April 17, 2006, 12:26am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/5 "2006-04-17T00:26:39Z")
Oops, forgot the link: > [@Fear Itself](#): > > [The detailed ships log was not widely used until 1850, when the Royal Navy made it mandatory](http://www.merchantnavyofficers.com/crow.html): ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [April 17, 2006, 12:42am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/6 "2006-04-17T00:42:41Z")
Last year, a semi truck lost it on an UPHILL turn and rolled it about three miles from my house. It was witnessed that the driver grabbed something from the cab, ran into the woods and came back to the truck and layed down pretending to be injured. He kept two logs. One for his employer, and one for the State. He hid his real hours in the real log in the woods. He fell asleep at the wheel, and luckily did not kill anyone. It sucks. A semi-driver is only paid for miles. And their employers push them way, way to hard. ---
**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\ **Post date:** [April 17, 2006, 4:39am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/7 "2006-04-17T04:39:49Z")
> [@enipla](#): > > It sucks. A semi-driver is only paid for miles. And their employers push them way, way to hard. You want the real ugly ones…short haulers. Many DOT regs IIRC do not apply to drivers who operate within 100 miles of their base. So places like LA and the San francisco bay area could have guys working 14-16 hour days and doing maybe 200 miles a day. They are usually hourly not mileage. ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [April 17, 2006, 5:05am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/8 "2006-04-17T05:05:00Z")
I’m getting scarily close to having two decades’ experience as a maritime lawyer. If I were Ambrose Bierce, my answer to this question would be as follows: “To have apparently contemporaneous written corroboration of the version of onboard events that the ship’s master would like third parties to believe to be true.” ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [April 17, 2006, 5:08am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/9 "2006-04-17T05:08:09Z")
> [@Princhester](#): > > I’m getting scarily close to having two decades’ experience as a maritime lawyer. If I were Ambrose Bierce, my answer to this question would be as follows: > > “To have apparently contemporaneous written corroboration of the version of onboard events that the ship’s master would like third parties to believe to be true.” In the words of the Guiness guys, “Brilliant!” ---
**Author:** ![Viscera](https://avatars.discourse-cdn.com/v4/letter/v/258eb7/32.png) [@Viscera](https://boards.straightdope.com/u/Viscera)\ **Post date:** [April 17, 2006, 5:29am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/10 "2006-04-17T05:29:30Z")
My current position involves assisting ship captains on their trans-ocean voyages, with regards to weather forecasting. Now, I don’t know everything that is part of the log, but captains do send us daily reports, with stuff such as weather conditions, distance sailed, current position, fuel consumed, comments/remarks, etc. This helps us determine the best route to take across the ocean, taking into account weather/safety, client needs, and other things. Basically, if anything happens down the line legally (could range from anything from vessel/cargo damage, vessel not performing up to the contract between the shipowner and the charterer, etc.), the log is the certified record of the ship captain, and everything he reports in it is true to the best of his knowledge. ---
**Author:** ![Snooooopy](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Snooooopy](https://boards.straightdope.com/u/Snooooopy)\ **Post date:** [April 17, 2006, 5:34am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/11 "2006-04-17T05:34:20Z")
So Captain Kirk would have something to say at the beginning of each episode. ---
**Author:** ![The\_King\_of\_Soup](https://avatars.discourse-cdn.com/v4/letter/t/a87d85/32.png) [@The\_King\_of\_Soup](https://boards.straightdope.com/u/The_King_of_Soup)\ **Post date:** [April 17, 2006, 5:34am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/12 "2006-04-17T05:34:30Z")
And all this time I thought a ship’s captain’s log was just a personal flotation device. ---
**Author:** ![ScoobyTX](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@ScoobyTX](https://boards.straightdope.com/u/ScoobyTX)\ **Post date:** [April 18, 2006, 3:40pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/13 "2006-04-18T15:40:01Z")
> [@BrainGlutton](#): > > I can understand why Navy captains would keep logs – the military wants to keep meticulous records of everything. But in the film _Dead Calm_ – [http://www.imdb.com/title/tt0097162/](http://www.imdb.com/title/tt0097162/) – a man who is simply taking a sea vacation with his wife in his private yacht logs everything that happens, the ship’s location at every day, in highly technical nautical language – what use would such records be? The “man who is simply taking a sea vacation” is a Navy captain in the film (established in the first scene). He would probably keep a detailed log just out of habit, plus as an nostalgic tie-back to the age of sail in naval warfare. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [April 18, 2006, 5:36pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/14 "2006-04-18T17:36:39Z")
Couldn’t find a good webpage defining “rutter”, but I did find this quote from a Rutter Technologies [newsletter](http://www.mun.ca/marcomm/gazette/2002-2003/feb20/research.html): > [@](#): > > “Centuries ago, pilots (navigation officers) used small books called rutters to record the detailed observations of a voyage and assist them in navigating the world,” explained Byron Dawe, president of Rutter Technologies. “Noted within its pages were the aspects of the journey necessary for them to retrace their voyage safely, and so the rutter was the navigator’s most prized possession. Our Voyage Data Recorder (VDR) is a modern day version of these rutters, recording all the critical elements of the voyage.” I believe the concept of the ship’s log is descended from the rutters used in the in the early days of navigation – speciifcally, the days before the invention of reliable chronmometers made the calculation of longitude easier. Sailboat ---
**Author:** ![LiveOnAPlane](https://avatars.discourse-cdn.com/v4/letter/l/3d9bf3/32.png) [@LiveOnAPlane](https://boards.straightdope.com/u/LiveOnAPlane)\ **Post date:** [April 18, 2006, 8:22pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/15 "2006-04-18T20:22:26Z")
> [@Sailboat](#): > > Couldn’t find a good webpage defining “rutter”, but I did find this quote from a Rutter Technologies [newsletter](http://www.mun.ca/marcomm/gazette/2002-2003/feb20/research.html): > … This may not be the place to mention this, being GQ, but your post reminded me of many mentions about rutters in Clavell’s “Shogun.” It being fiction, who knows how accurate he was, but the info on them and their extreme importance in the days before longitude could be accurately determined was very fascinating to me. Again, I do apologize if I have erred/sinned. :o ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [April 18, 2006, 8:52pm UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/16 "2006-04-18T20:52:47Z")
> [@The King of Soup](#): > > And all this time I thought a ship’s captain’s log was just a personal flotation device. I thought it was what Kirk left behind when he went to the bathroom. (Which also floats.) ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [April 19, 2006, 9:24am UTC](https://boards.straightdope.com/t/why-do-ships-captains-keep-logs/352923/17 "2006-04-19T09:24:23Z")
Reminds me of the story where the first mate looks at the previous day’s entry in the captain’s log: date, time, course, speed, weather, and remarks. Under “Remarks” the captain has written “The first mate was drunk today”. The first mate objects to this, but the captain points out it was perfectly true; the first mate admits that this was so (it was his birthday, and he had saved a rather good bottle of brandy since leaving port five weeks previously in order to celebrate privately) but that the ship’s owners will see only the log entry and it could set his career back several years. The captain says that this is just too bad, since the log entry is no more than the truth. So later the captain finds the first mate’s log for the day which also date, time, course, speed, weather, and remarks. And under the last column the first mate has written: > [@First Mate](#): > > The captain was sober today.