Apparatus and method for liquid level measurement in a sounding tube

A level sensing apparatus for attachment to a vessel to measure levels of contents in a tank of the vessel. The level sensing apparatus includes a housing, a transmitter disposed within and operatively connected to said housing, and an antenna operatively connected to the transmitter for directing electrical and/or mechanical waves in a direction away from the transmitter. The antenna is further adapted to receive electrical and/or mechanical waves. The level sensing apparatus further includes a mounting system affixing the level sensing apparatus to a vessel. The mounting system is adapted such that the mounting system can be placed in a first position while the transmitter is affixed to the vessel, wherein levels of contents in a tank can be measured with electrical and/or mechanical waves, or in a second position while the transmitter is affixed to the vessel, wherein levels of contents in a tank can be measured manually.