Over half of all fishing fatalities are due to vessels going down, and most of the boats sink because of flooding. The sinkings of the Alaska Ranger and Katmai in 2008, for example, in which 12 men died, both stemmed from flooding through open hatches.

Those and other sinkings highlighted the need for an alert that provides immediate status of all openings aboard fishing boats. To the rescue: a simple electronic monitoring system on doors and hatches that sends signals to the wheelhouse.

It’s not new technology, said Chelsea Woodward, an engineering technician with the NIOSH commerci...