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What do Mark Twain and your depth sounder have in common?

A recent trip to Disney World in Florida and a subsequent ride on a paddle wheeler reminded me of something I had long forgotten. Thought some of you might be interested in how depth was measured in the "Ol days." Actually, lead lines are in use today, although sparingly. I still carry one onboard, although it is a modern type. Capt. Matt

Mark Twain came into the world as Samuel Clemens on November 30, 1835, in Florida, Missouri. His parents moved to Hannibal, Missouri while he was a young'un, and he spent his youth experiencing the adventures that shaped his life and colored his writings. At 24, he realized a boyhood dream when he was finally entrusted with the powers and duties of a steamboat pilot on April 9,paddlewheeler.jpg (3271 bytes) 1859 in St. Louis.

Twain loved the paddlewheel steamboat and he loved the river. As a matter of fact, it was during his years on the river that he chose his pen name. "Mark Twain" was a frequent call of the leadsman. It meant that the water was 2 fathoms (12 feet) deep and indicated safe water.

leadline.gif (2489 bytes)A leadline is used to determine water depth and the type of material which makes up the bottom or riverbed. A 30-foot-long line is attached  to a pipe filled with lead, except for the bottom 2 inches. (Modern leadlines are simply a solid round pipe-shaped piece of lead with a concave bottom) Material from the riverbed...mud, sand or potentially hazardous rock...collects in the lower, hollow end of the pipe.

The line itself, in the "Ol days", was probably made of manila, hemp or sisal, and had markings woven into the strands which represented various depths. Today's lead lines generally have polyester strands and bright colored plastic tags with actual numbers are woven into the strands

The leadsman is the person who "heaves the lead" and "sings the mark". In the days of Mark Twain, the mark meanings were actually sung as the paddle boat cautiously made its way along the river in potentially shallow water.

Meaning of the Marks on the Leadline:

"Quarter Less" = minus 1-1/2 feet
"Quarter" = 1-1/2 feet
"Half"= 3 feet
"One" = 6 feet

"Mark One"

6 feet above the lead, one strip of leather is woven in.
"Quarter One"
7-1/2 feet above the lead, a white piece of cloth is woven in.
"Half One"
9 feet above the lead, a red piece of cloth is woven in.
"Quarter Less Twain"
10-1/2 feet above the lead, a black piece of cloth is woven in.
"Mark Twain" (safe water)
12 feet above the lead, two leather strips are woven in.
"Quarter Twain"
13-1/2 feet above the lead, a white piece of cloth is woven in.
"Half Twain"
15 feet above the lead, a red piece of cloth is woven in.
"Quarter Less Ta-Ree"
16-1/2 feet above the lead, a black piece of cloth is woven in.
"Mark Ta-Ree"
18 feet above the lead, 3 leather strips are woven in.
"Quarter Ta-Ree"
19-1/2 feet above the lead, a white piece of cloth is woven in.
"Half Ta-Ree"
21 feet above the lead, a red piece of cloth is woven in.
"Quarter Less Four"
22-1/2 feet above the lead, a black piece of cloth is woven in.
"Mark Four"
24 feet above the lead, one leather strip, with a hole in it is woven in.
"No Bottom"
Any depth over 24 feet.

 

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A Quick History of Navigation (BoatSafe Kids)

 

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