Never waste a moment to tell a good story. Usually, you’ll find informative or educational stories on this platform. This time, I literally found an opportunity to tell you a fun story. All it took, was this nifty little classic navigational instrument. The crew on the dredge used to calibrate their modern survey system1 or checked the delivered depth with this ancient tool. Ever seen one like this? It is a depth sounding lead2. Well, I doubt this one was made from lead, based on the estimated weight and appearance, but it does have all the other characteristics of a normal depth sounding lead.
Evolving from a stone on a rope, the depth sounding lead was used to sound the depth. The plummet was made from lead. The rope was marked at regular intervals according to the shoe size of the current king. Cast overboard, the lead sank and keeping the rope tight, the depth at that location could be read from the markings on the vertical rope. It involved some nimble dexterity to stand at the lee side of a fast moving vessel in a choppy sea to handle the lead, a bundle of coiling rope and accurately reading the depth at the right moment. Hands down to all those seafarers that explored the world in old times and managed to navigate the globe on this instrument.
The depth was not the only information gained from this action. When you look closely, there is a hole at the bottom of the lead. On the picture above it is empty, but it ought to be filled with grease or wax. When the lead touched the bottom, some of the dirt was caught in the grease. When the lead was retrieved, the cling-ons were inspected. These could be either: sand, mud, gravel, peat, silt or even shells and other biological detritus. The material was reported on the charts also. This made navigation in charted waters easy: compare the sample with the indicated bottom condition. And that brings me to my fun story.
Before the Dutch reclaimed their land, there was a large water body in the Netherlands, called the ‘Zuiderzee’3. Or, South Sea as opposed to the North Sea, which most of you might know. This Zuiderzee, was extensively used for fishing. The skippers did not have charts, but they relied on oral tradition handed down through the ages of where what kind of soil would be available. Near Urk, you might find rocks. Near Pampus, there will be a lot of mud and around Stavoren, there is the famous ‘Vrouwenzand’ (Sand Bank of the Lady of Stavoren4). So, when the fishermen cast their depth sounding leads out, they knew the location of their vessel and the depth beneath it.
One of those skippers boasted he did not even have to see and feel the sample, but just by tasting it, he could pinpoint his location within a hundred yards. Hard to believe, right? The cabin boy on board thought likewise. So, he devised a cunning plan. After lunch, the skipper went down to the cabin for a short nap and instructed the cabin boy to bring him the lead to taste the sample. But, our clever cabin boy sank the lead in the crate with potato’s. The bottom of the crate was covered with clay from the potato’s. Carefully bringing the sample to the skipper, the cabin boy woke him up and awaited his reaction. The skipper woke up groggily and grappled for the lead with half closed eyes. He stuck his finger in the sample hole and tasted the material inside. Suddenly, his eyes went wide open and he exclaimed: Oh, disaster! The dikes have broken again! The land is flooded and we are sailing over farmer John’s potato patch!
- Positioning and survey system, Damen
- Depth sounding, Wikipedia
- Zuiderzee, Wikipedia
- Lady of Stavoren