No matter whether the vessel is in port or at sea, sound at least a day from the sounding pipe or measure by the remote level gauge. If remote level gauges are used for the daily soundings, these shall be periodically verified for accuracy by comparing manual soundings with gauge soundings. Sounding pipes on exposed decks may not be sounded when unsafe to do so as in heavy weather. Any abnormal soundings are to be investigated and reported to the office.