depth. In order to obtain an accurate sounding, all this must be done smartly, more especially if the vessel has much speed on her. It is often advisable to heave the vessel to while sounding.
It is the custom at sea for the leadsman after taking a cast of the lead to sing out the depth in marks and deeps. Thus if the first piece of red bunting is on the surface of the water, indicating a depth of seven fathoms, he calls out 'By the mark seven.' If the five-fathom mark is submerged and the seven-fathom mark is six feet out of the water, he calls out 'By the deep six.' The depths are calculated to quarter fathoms; thus if the depth be a quarter of a fathom more than six fathoms, this would be announced by the leadsman as 'By the deep six, and a quarter six.'
Always take soundings on the windward side of a vessel: if you throw the lead over on the lee side, the leeway of the vessel will cause her to drift across your line, which may consequently get foul of keel or rudder.
There is a hollow at the heel of a lead, and if this be filled with tallow (the process is called arming the lead) a cast of the lead brings up a specimen of the bottom, mud, gravel, shells, as the case may be. This is often of great service—in foggy weather, for example, when landmarks are not distinguishable—for if one compares the depth of water and nature of the bottom as given by the lead with the similar indications on the chart, the position of the vessel
