Thanks all for your replies.
I did notice there are two models for the sensors. I have difficulties understanding how the straight one would sit in the hull given it’s position. At present it’s still working so no immediate action required.
I did look at the ultrasonic version as well, maybe a more sensible upgrade path. I’m thinking about replacing the current stuff B&G and Furuno Navnet 3d with a full suite of Furuno to reduce the number of brands and to reduce the massive amount of power the Navnet Blackbox is consuming. My first activity was to upgrade the monitor at the navigation desk with a touchscreen panel to support the new blackbox from Furuno.
The new blackbox solution from Furuno takes only 30% of the power the Navnet 3D is taking. I don’t really like the B&G gauges at the helm as well, they take up a lot of space and provide little information for the space they take up. They feel a bit outdated to be honest. But the total pricetag for the upgrade is still quite scary...