• BJ

Ship's Logs: The Bane of Big (Sometimes Useless) Data

In June 2020 I published a blog post explaining why I don't use commercially produced logbooks, or electronic log book apps. In a nut shell, unfortunately most of the commercial logbooks and available apps try to be the Swiss Army knife of ship-board logs, they tend to be overly complex, and include unimportant entries because someone thought it might be a good idea for something. Don't get me wrong, it's not that I don't log information that's important to me. I just don't waste time logging bits of useless data that doesn't benefit me or others in some way. For example, I don't record wind speed and direction every hour. I don't care 1 week from now that the wind was 10 knots out of the southwest, and an hour later it was 7 knots out of the west. Instead I focus my efforts on recording and preserving that data that is useful to me, or others in some meaningful way.

Data Rule #1 - Don't collect data that doesn't serve a useful purpose. You can spend a lot of time collecting data, and waste a lot of time trying to figure out ways to use before you finally realize you are pursuing a Sisyphean task.


Of course there is some data we might want to preserve. For example, most paper log books provide entries for logging latitude and longitude at periodic intervals (along with a bunch of other 'stuff'). This is useful data if you plan to manually plot tracks of your passages to keep a record of where you have been. But, there are currently many ways to automatically record passage tracks whether you are sailing inland waters, coastal cruising, or crossing oceans and electronically plotting that information to a digital map more pleasing to the eye and more easily sharable. Underway I use Iridium Go and a Predictwind tracking page to plot my tracks in real time. I also have a Class B AIS system that shows positional data. But, there are many other alternatives. This can be important to demonstrate your passage was non-stop. (as is required by the Fiji Blue Lane process during this Covid pandemic)


Data Rule #2 - If you can automate the collection of data that you want...do it! Simplify your life!


To use the data that's important to you will probably require some calculations, tracking, and analysis to see if you are reaching your goals (after all...if you don't have specific ideas/goals in mind...then you should ask yourself, "Why am I collecting this data?"Computers (including 'smart phones') are intended to make our lives easier and minimize mundane tasks. Writing things down in a log book (maintenance log, position log, etc.) is mundane. Performing tasks such as calculating averages, plotting tracks on a chart, budgeting, scheduling reminders on a calendar are also mundane tasks. (Sure we should learn how to do those things just in case the sun explodes and the resulting EMP blast wipes out all electronics, but I'm pretty confident that if that happens none of us will worry about logging data or calculating averages.) Welcome to the 21st century. Virtually every cruiser I know has a cell phone, 1 or more tablets, and laptop computers onboard their boats. While many people still find it "comforting" to write things down in log books, computers make data much more easily accessible/searchable, and much easier to manipulate (calculations, create visual charts and graphs, etc.).


Data Rule #3 - Make the data easy to collect so you can make the data work for you, and provide you with the information you want.


Apps for Data Collection and Management.


As I wrote in my previous post on logging I downloaded and tested many free and 'pay-to-play apps to find one that would best suite my needs. I tested My Captain, NauticLog, Boat On Pro (French only), Ship’s Log for Captains, Tracklink NauticEd, Logbook Suite, Boating Suite, Keep Sailing, Sailor LogBook, Odyssea, Skipper Tools, Aiolos Lite, Yacht Panel, and a few others. Unfortunately, most of these apps were merely electronic versions of paper logs, and offered very little customization. Some were only useful with a cell/internet connection, and some only worked on a cell phone.


But, the good news is that these logging apps are all simply database apps with a pretty face (user interface) on them. So, I thought, 'why not get a simple database app, and create mulitple tables and custom fields for the specific data I wanted. But, there were a few very important "features" that are critical for my use since when I am on my sailboat I am frequently out of cell range, and rarely have Internet access 7 days a week. So, here are a few key features that are important to me...

  • Simplicity - My general rule of thumb for software is the number of "features" is inversely proportional to ease of use. If I can't install/download an app, and it is not immediately instinctively useful...then it's crap. I know some advanced features might take a little investigation, but the app should do the basic things I need right out of the box! Having worked in the software industry for over 20 years if I can't install and app and figure out it's basic functions in 5 minutes...it's a crappy app that gets deleted.

  • Customization - Being able to customize the app, or the data entries enables you to focus on the data that's important to you, helps to create an uncluttered input and presentation, and allows you to personalize the data entries.

  • "Off-Line" Capable - This blew my mind. I don't know how many apps for phones or tablets will not even launch or allow input if there is no cell data or Internet connection to the device. What nonsense and arrogance of developers who think everyone lives in a 24/7 connected world!!! As mentioned, I am not always in cell range or have Internet connection...if I am at sea and want to log some bit of information and the app doesn't work...it's crap! For example, I really liked Airtable database app, but when I tested its offline support I quickly discovered the app wouldn't even launch. This was a nice app but it's absolutely insane not to enable offline data entry.

  • Works on Multiple Devices - I have big hands. I dislike using a phone to enter information. I don't even like text messaging. (I'm sure there is some technical term for "big finger; little keys.") And, viewing things like nautical maps and such on a phone makes my head hurt. Onboard my vessel I have phones (Apple and Android), iPads, and laptop computers (Windows and Mac). If an app cannot work on at least 2 of these devices...it's crap! Remember, I'm not talking about games, social apps, etc., I'm talking about apps that I want to record data with and will likely need to make annotations or input some data or notes. So, an app that works on a cell phone, and a tablet is great. One that works on those and a laptop even better. And, an app that works cross platform is outstanding!

  • Syncs Data Between Devices - This is related to apps ability "working on multiple devices." The apps I use to keep important information have to be able to sync and share data and updates seamlessly either by cable connection, Bluetooth, or cell data/Internet connectivity. I am a big believer in redundancy! Should 1 device fail, I may lose some information, but as long as I sync data I will not lose all the information I value.

  • Supports Cloud Storage - This also relates to the sync issue above. Sync'ing between devices is important incase 1 device should fail. Cloud storage is important because it not only enables sync'ing between devices when connected to the Internet, but when the latest data is uploaded to the Internet 'cloud' it is a permanent record of the information you wanted.

  • Ease of Data Use - For me this includes everything from sorting the data, searching on the data, data calculations, and data presentations. We collect data for a reason, so if we can't make it work for us and easily give us the information we want from the data...there really isn't much sense in collecting data to begin with.

A log book, regardless of whether it is a passage log, a maintenance log, a budget log, a radio log, etc., is simply a repository of data. That's why a database application is the perfect solution. Since I have 2 iPads onboard S/V Discovery I opened the AppStore and searched for databases. I tested MySQL, Airtable, MobiDB, Ninox, FileMaker, and MyStuff 2 Pro. I settled on MobiDB because it was the only one that satisfied the majority of the "features" I demanded. (It could be much better it the developers did a better job of allowing the customer to customize the data input fields.) A well maintained log also serves as evidence for customs/immigration officials, and for insurance purposes should there ever be a need.

My Ship's Logs are managed on iPads and other devices.

Daily Ship's Log

Hours Underway / Distance travelled / Average Speed - Every sailing day I enter hours underway, the distance travelled, and the average speed whether it is a 3 hour day sail (I am rarely out for less than 3 hours), or a long multi-day passage. For multi-day passages I usually enter a record every 24 hours. Hours underway provides evidence of sea-time for USCG license requirements. Sailing is never in a direct line, so I track the distance between ports to get an average. Time and distance underway are included in my sailing resume, and insurance companies often ask for this to gauge experience. The distance travelled and average speed help me plan the approximate sailing time between ports; especially important on longer multi-day voyages.


Engine Hours - This is a no brainer. I record this in my daily log for 2 reasons. First, and most importantly are for tracking service intervals. If I really wanted to, I could also use this to calculate time under sail vs. time motoring. However, that is not really important to me. Time underway is the important number.


Maritime Segment - This is used for USCG requirements and also helpful to document experience for insurance purposes. The USGC OPUV license has a "Near Coastal" endorsement and at least 90 days (of the 360 day requirement) must be beyond the US baseline. (Hint...Puget Sound/Salish Sea are inland waters.)


Crewed vs. Single-handed - I keep track of this for my own personal value, but it's also valuable if I ever need to prove that I had crew aboard for insurance purposes. This is mostly personal.


Daily Journal Entry - To me this is the most important part of my "Daily Ship's Log." It is a daily narrative of my experiences, the things that happened that day, and sometimes just my thoughts or rants. The most interesting things about the log books of famous seafarers like Captain Cook, or Captain Bligh are not their meticulous logging of positional data, but the journal entries. Now, I am no Cook or Bligh, but my family and friends do occasionally enjoy my journal entries ("blog posts" that are also uploaded at least daily to my PredictWind tracking page and later converted into passage note blog posts with photos.)

My daily log used to store information important to me.

Position / Speed / Course - I don't enter position speed and course into my "ship's log." But, I do keep track of it electronically. (If I had to do it manually, I would only do so every 24 hours.) Honestly, I don't care that on Oct 11 at 1400 UTC I was on a heading of 245 degrees true at 6.7 knots. That information is of zero value to me on October 11 at 1500 much less any time after that. But, I can get it if necessary. However, when I am underway I use my Iridium Go to automatically update my position hourly to a tracking page on the PredictWind site. (It just happens to record course and speed at the same time.) Tracking position is important to me for 4 reasons. First, it allows friends and family to track my progress and see where I am in the world. Secondly, should my course change radically or my position stops being updated it is an early warning that I may have encountered some difficulty to family members who I remain in close contact with. Thirdly, it is available to authorities to show that I made a non-stop voyage. During this pandemic voyaging from Hawaii to Fiji requires a non-stop passage. This is also tracked via AIS. And finally, it is a personal visual record of my voyages. Also, I will admit that I do enter this information daily on multi-day passages into my Weather Log, which I keep for the daily call in to the Pacific Seafarer's Net on 14.300 Mhz. They use YOTREPS information for voluntary observations from mariners reporting (MAROB Program).

My lat/long, speed, and course data are automatically posted hourly to Internet in real-time.

My Other Logs

During passage I do keep a daily Weather Log. The only reason I keep such a detailed log is because I check-in to the Pacific Seafarer's Net when underway making passages. The PacSeaNet collects the YOTREPS data for the The MAROB Voluntary Marine Observation Program. I only post 1 record a day at 0300 UTC during passages; I don't update this log daily.

OK...a Radio Log is a nerdy log, and completely unnecessary. However, I am an avid ham radio operator, so keeping a radio log is almost second nature. I also record latitude and longitude here for annotating on the QSL cards for maritime mobile operations to land based hams. But, I also track all "official" communications aboard e.g. calls to other ships at sea, calls to foreign ports, and esp. calls to SAR services. Yes...it's a nerdy thing.

An Expense Log is another unnecessary log, but at the end of the year I like to see how my money was allocated and to review spending habits. I'm not on a really tight budget, but should the stock market crash I might need to adjust some spending habits. I have expenditures divided into the following expense categories; Anchorage/Mooring, Boat Insurance, Customs & Immigration Fees, Entertainment, Food & Beverages, Health Insurance, Marina Moorage, Medical & Dental, Miscellaneous, Navigation & Safety, Maintenance, Port Clearances, Taxes, System Upgrades, and Travel Expenses.

A boat is a hole in the water into which a person throws money, and the more you work on you boat in exotic locations the more maintenance will become necessary. So, I do keep Maintenance Log of all period maintenance, repairs, and also new and/or upgraded systems. These records have proved useful when asked about what size cutlass bearing is installed, the size of the PSS bellows, and other details about the boat. It also documents periodic service intervals on the engine and other systems on the boat, and details repairs and upgrades should I ever want to sell S/V Discovery.

The Medical Log is a new log that I started in 2021. Due to the current pandemic the few countries that are open want to know that anyone arriving by yachts are free of the Sars-Cov-2 virus. Some countries require documented temperature checks twice daily during passage. The medical log is also beneficial to track vitals, administration of medicines, and symptoms if someone onboard becomes ill. Since MobiDB can export this information as a PDF file it is very simple to pass this information onto qualified medical personnel rather than trying to remember it. (And yes, my med kit contains all the necessary tools and I am trained on taking vitals, and advanced first aid measures.) This log also corroborates the administration of prescription medicines aboard the vessel.

Table of all prescription medicines onboard S/V Discovery.

And finally, I also created a Prescription Medicine Log to replace my hand-written papers listing out onboard medications. This was created this year also for ease of maintaining lists of medications on the vessel. Many countries require that all prescription medications be listed on the custom's form along with quantity. This list not only includes the medications in my med kit and rapid ditch bag, but also all prescription meds brought on my any member of the crew. Again, I can export these records in PDF format or easily transcribe them onto the customs forms. If a crew member departs the boat, I simply delete those records. Since all crew members aboard have access to my primary iPad (used for weather downloads, back up navigation, and logging (and maybe a few music videos), any member can also look up the medications onboard, know where they are at, and know what they are for and how to administer them in case of emergency (i.e., I am the one that needs help).


So, that's a view into my logs and my logging onboard S/V Discovery. I try to automate as much information as possible, but I also try to refrain from collecting data simply for the sake of collecting big data just in case I might need it 'someday' - because more often than not 'someday' usually never comes. Also, if your not going to be using the information for some useful long-term purpose then ask yourself, "do I really need to create a permanent record of this data?"