A sensor mounting assembly is configured for use with a vessel arrangement including at least four vessels. The assembly includes first and second elongated frame members, first and second rollers, and first and second sensors. The first sensor is attached to the first elongated frame member and is configured to contact the surface of the first vessel upon actuation in a first direction. The second sensor is attached to the second elongated frame member and is configured to contact the surface of the second vessel upon actuation in a second direction that is substantially orthogonal to the first direction. This disclosure also describes a method of mounting at least six sensors for use with a vessel arrangement including at least four vessels, the vessel arrangement disposed in a container in a two-by-two stacked configuration having a central space.