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The Importance Of An Engine Log

Archiving Your Engine. Keeping track of your powerplants on paper can be simple and easy and may prevent big problems later on.

Voyagers have a long tradition of record keeping. Captains from James Cook of the Endeavor to James Kirk of the Enterprise maintained logs that exhaustively detailed their travels and adventures. But a ship’s log was never primarily just a form of adventure writing; rather it was the definitive account of a voyage maintained primarily for the benefit of future captains and masters who could learn from the details therein—what reefs to avoid, what islands harbored cannibals, and so on.

Engine logs not only keep track of all things vital, but can alert you as to what may lay ahead.

Engine logs not only keep track of all things vital, but can alert you as to what may lay ahead.

When I began boating it was fairly common to maintain a log, in this case more a diary of pleasures, lessons, and near misses. For years I kept the log of my second powerboat, a tattered, dog-eared spiral binder. Scanning the pages of that document—bespotted with the spillage of various beverages—brought me much joy in subsequent years, and when the log disappeared in one of my many moves, I felt I’d lost a link to my past.

Nostalgia is a great reason for keeping a written archive of your travels, but there are practical benefits also. A log can be a valuable record of the condition of your vessel and the work performed on her, and this is especially true in the matter of engines. Even if you have no desire to write down your travels, you should maintain some sort of written record of the performance and maintenance of your engines.

Before you groan with revulsion, let me assure you that a proper engine log need be neither complex nor time consuming. It can be part of your ship’s log, if you keep one, and if you don’t, a simple notebook with a durable cover will suffice; smaller is better given the traditional lack of stowage space aboard. You’ll want to keep yours near the helm so you can make entries as they occur. Log keeping, like so many other tasks, is a job that once deferred is quickly forgotten.

What goes into your engine log can be basic or complex according to your taste. Some like to record everything from fuel taken on to rpm settings; others prefer brevity. Wherever you fall on this spectrum you’ll want to be consistent and include a few basics. The date of your entry is an obvious one, but along with it should also be the engine hours. After this should come specifics like work performed—for instance, if you had the oil and filters changed. (Cross-reference this with the file you keep off the boat—for obvious reasons—containing receipts and job orders.)

Remember that fabled little black book you always heard of? Your engine produces all the content you'll ever need.

Remember that fabled little black book you always heard of? Your engine produces all the content you'll ever need.

You’ll also want to record the addition of lube oil, coolant, and additives. A friend, who certainly qualifies as Type A, writes this information in red ink so he can monitor oil and coolant consumption at a glance and be forewarned of any unusual trends. Obsessive he may be, but unusual fluid consumption is often a sign of future problems.

Of course you should also record unusual engine-related events, such as mechanical malfunctions. And don’t limit yourself to major issues. Even minor annoyances are important and should be included. Remember: You’re creating an archive to help you understand larger issues.

I recall an owner who repeatedly recorded in his log a noisy drive belt, even though he was able to tighten the bracket and quickly put a stop to it. One day while scanning his log he was surprised to learn just how frequently he’d done this. He consulted his mechanic, who after a bit of snooping discovered the threads on the bolt securing the bracket to the engine block were stripped. Eventually it would have failed and the bracket would have come loose and stopped the engine.

Whether to record the fuel taken aboard and from where it came is another matter of personal preference. The desire for brevity and lack of hassle argues against it but the information can help you trace the source of substandard fuel. Those of you who travel to Mexico and the Bahamas know that not only can fuel quality vary greatly from port to port but that lousy fuel often comes repeatedly from the same source.

The final category in your basic engine log is, in my opinion, the most important one: your impressions. An experienced captain has a sixth sense about engine issues. Even when everything seems to be going swimmingly, he or she can sense that something’s not right. It might be a sound or vibration, or maybe something more elusive. Imprudent boaters ignore such signs but savvy ones record them for later reflection. They may mean nothing—they often do—but they may also be early warning signs of trouble.

Which is why, after you’ve gone to all the trouble to maintain a log, you also need to read it occasionally. You may be surprised at what is revealed, everything from overdue maintenance to a surprisingly persistent malady. Kirk no doubt left this job to Spock, but I’m sure Capt. Cook spent many a night personally perusing and reflecting upon his log entries. But then he wasn’t concerned about engine problems.

This article originally appeared in out affiliate publication, Power & Motoryacht, and can be seen here.