The best skippers are careful listeners and very in tune with the sounds produced by their engines.

A Good Ear

It pays to be acutely aware of noise on your boat, particularly if it’s coming from the engine room.

I’m not a big fan of loud music when I’m cruising on my boat. While I love music, I think it’s best to keep it at a reasonable sound level rather than blasting tunes for everyone in the marina or anchorage to hear. And there’s another reason to turn the volume down: Music can distract you from other noises on board, including those in the engine room. A builder told me a sad tale about a skipper who chose to run a boat from the flybridge while wearing headphones. He wanted to listen to his favorite bands rather than the throb of the machinery underfoot. It wasn’t until the tachs started fluttering that the captain pulled off the headset, only to hear the smoke alarms ringing. I don’t think he was listening to “Light My Fire” at the time, but even so, the boat’s owner fired the guy when he found out what he’d done.

Boats are noisy, and some sounds are good. On one delivery run I made from New Jersey to Florida, I encountered an electrical problem at a marina; the shore power couldn’t keep the bait freezer and other refrigeration running. I started up the generator, all the while thinking about the several hundred dollars I’d spent on the mullet, balao, squid and Spanish mackerel that needed to be preserved. When the Onan was up and operating, it was music to my ears.

Other machinery sounds can reveal less fortunate news, including a squealing from the cutlass bearing. A worn cutlass bearing will take its toll on a boat’s performance. I was reminded of that on another delivery from Connecticut to New Jersey. I was approaching Montauk Point when the throaty exhaust from the boat’s Detroit Diesel 8V71Ts changed to a distinctly hollow sound. Even before the water temperature gauge responded, I knew I had a problem with the engine’s water pump. I raced down the flybridge ladder and peered over the transom. I saw that the port engine was pumping fine, but the exhaust flow coming from the starboard side was no more than a drizzle. We ended up limping into a marina on one engine, and the worn impeller cost us a travel day, but it could have been a more serious repair had the motor overheated, particularly since we later discovered the engine alarms were not working. On that day, the ability to recognize changes in the noise produced by engines really paid off.

engine room

Modern marine propulsion—including diesels, inboard gasoline engines and outboard motors—is equipped with sensors in the systems for cooling, lubrication and fuel, and these sensors perform watchdog duty to prevent catastrophes, often by slowing the engine and reducing its power output. Get familiar with these features because they are designed first and foremost to protect the machinery from damage, not necessarily you or the boat. If an engine sensor detects a problem with fuel or lube, for instance, it could reduce the RPM output. If that occurs when you’re at the wheel, hopefully you’ll have enough speed to safely negotiate the boat through traffic, a rough inlet or strong currents. Prepare in advance for that type of situation by reviewing your owner’s manuals.

You should also test the alarms on board a few times each season. These devices, like so many things aboard a boat, age even if they’re never activated or used. I like to pull the kill switch lanyard on my outboard boat once a week just to make sure it’s operating properly. Whether I’m running at cruise in the ocean or puttering at a slow pace on the river, I want to hear that engine go silent when I yank that cord. It’s one of the most soothing sounds I know.

Marine Diesel Maintenance & Troubleshooting:

Want to learn even more? The diesel engine is the beating heart of your boat. Arguably, a good running engine is your most important single piece of safety gear. Diesel engines are economical, long-lived and reliable, yet there are a number of ways in which they can fail. This seeming contradiction brings us to the distinction that has shaped the Online Marine Diesel Maintenance & Troubleshooting course.
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This article originally appeared in the June 2018 issue of Power & Motoryacht magazine.

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