We received an email from a reader several days ago who was curious about the need for a carbon monoxide detector on their diesel-fueled trawler. Apparently a friend had said it was a waste of money because diesel exhaust didn’t have any carbon monoxide (CO) in it.


CO Monitors have a finite life span of between 3 and 5 years. The expiration date can be found on the device.

This is an interesting question and sadly one where many boaters over the years have made fatal mistakes. Even the American Boat & Yacht Council (ABYC) safety standard is a bit lax on this topic. The current standard (A-24) that addresses carbon monoxide detection systems only recommends the use of these devices on boats with accommodation spaces and either a gasoline-fueled inboard engine or a gasoline-fueled generator set.

Although diesel exhaust has a considerably lower percentage of carbon monoxide than gasoline exhaust, it still has some. Today most (but not all) of the builders I’m familiar with are installing these detectors on all of their boats with accommodation spaces, whether gas or diesel fueled. I absolutely agree with this approach for several reasons.

First, it is not uncommon for boats to be tied up at piers or bulkheads or even rafted together where one boat might be running a gasoline generator and the diesel boat is just sitting there with its hatches open, creating the potential for some of the gasoline exhaust to enter the diesel-fueled boat. Second, in the event gas exhaust transfer does occur (and it has happened many times), the diesel-fueled boat owner may never know the risk until it is too late. Not having a CO detector on a diesel-fueled boat is false economy! In my view, you should have one of these devices in each cabin area of ALL boats.

If your boat already has one or more of these devices installed, remember they do have a finite lifespan before they need to be either replaced or sent to the manufacturer for re-calibration. Units I’ve worked with over the years have either a 3 or 5 year life span. The dating will always be found on the device so if you already have them on your boat, check the date label on the unit to make sure it is still within its safe use time period.

And if you don’t have one yet, gas or diesel, make this a top priority. It could save your life!