Accession Number

1986.008.0712

Alternate object names

Sounding Lead;Plummet;Plumb Bob

Creation Date

circa 1620

Description

This heavy sounding lead, or plummet, from the Spanish 1622 galleon Santa Margarita served as a weight to carry a line from the ship’s side down to the sea floor. The length the line traveled to the bottom told the ship’s pilot how deep the water was, an important measurement for maintaining a safe course. The recessed bottom of the lead was designed to hold tallow or wax. When the weight hit the bottom, the sticky substance would collect a sample of bottom material – whether sand, pebbles, or shells (if it came up clean, the bottom was rock). The sample could be compared to records of sea bottom composition charted by previous voyagers, which helped to establish a ship’s location. Dimensions: 29.4 cm L x 4.8 cm W x 3.25 kg.

Exhibition Label

Case Caption (2023): 

The Pilot

Aboard a Spanish ship, the pilot was third in seniority and would have had
over sixteen years’ experience. His training included mathematics and celestial navigation. He also had to be familiar with charts of the overall voyage and those
of the fleet’s destination in detail. He needed to understand changes in cloud patterns, shifts in ocean currents, and the quality of the ocean floor alongdifferent coastlines.

Aboard the Nuestra Señora de Atocha, the pilot, Martin Jiminez, secured his chest carefully. It was still intact when it was discovered by Mel Fisher’s divers almost 400 years later. It held plotting dividers, a small sundial, a cross staff, a jar, gold and silver coins, and gold chains. Most importantly, it held the astrolabe shown here as well as four others. The astrolabe was used to determine latitude. Certainty about the ship’s latitude combined with the pilot’s other knowledge, meant that the ship would reach its destination safely and on time. 
Object Caption (2023):

Sounding Leads
Lead (c.1620)
Gift of Jamestown Inc.
1986.008.0710, 1986.008.0712, 1986.008.0713, 1986.008.2014

The pilot would “sound” the depth of the water below the ship by dropping a weighted line over the side. When the line went slack, he would have his measurement. In addition, the end of the weight was filled with sticky wax that would bring up a sample of the ocean floor. His expertise enabled him to identify the different types of ocean bottom expected along different shores.