But the steamer is useful and practically unnoticeable except when it whistles.

There were extremely minor, practically unnoticeable vibrations of the ship from time to time.

My ex's physical activity would have only spiked for like 90 seconds so it would have been practically unnoticeable anyway.

As a matter of fact, this chimney long ago became nicely toned down by its native soot, and is practically unnoticeable.