The Use of Soundings for Navigation in the Mid-20^th Century

Abstract

Many ingenious mechanical methods were used by hydrographic surveyors for measuring the depth of water in the early part of the 20th Century. These were superseded by echo-sounding and sonar techniques in the later decades. Relatively few of the mechanical methods were used by merchant ships but, in the years before radar and satellite navigation, they, and the increasingly popular echo sounder, had a useful place in the navigator's armoury of navigation aids. This paper is not intended to provide a detailed description of the development of sounding devices. Sections 1 to 5 simply outline the principles of the sounding devices with which the authors were familiar during their time at sea. In Sections 6 to 9 the authors recount their anecdotal experiences of the way in which they, personally, used depth measuring devices during the middle years of the 20th century.

The Cinderella Navigation Aid The use of the Lead and Line in British ships from the 16th to 20th Century

“…By the beginning of the 20 th Century, the use of astro navigation for position fixing was a matter of routine. However, in overcast conditions which, especially in temperate latitudes, might persist for many days, soundings continued to provide a valuable navigation aid as discussed by Kemp et al (2008). This included the long established practice of locating the 100 fathom line when approaching the English Channel from the west or the south-west.…”

Astro Navigation Remembered

“…Lack of success might mean approaching a coast with only an approximate idea of one's position. This was especially fraught in poor visibility and, on one memorable occasion a position, misjudged by 25 miles, caused our ship to steam into Bantry Bay while under the impression that we were feeling our way eastwards along the south coast of Ireland (Kemp et al, 2008, Section 8.2).…”

“…Achieving a cross from a Consol bearing and an astro position line was a satisfying experience, although looked on with suspicion by the old school of shipmasters. For more detail with Consol, see Sven Gyldén's experience (Kemp et al, 2008, Section 8.4).…”

Coastal Navigation in the Mid-20th Century

“…This is the third in a series of papers about various aspects of merchant ship navigation in the mid-20 th Century. Previous papers concerned Soundings (Kemp et al 2008) and Compasses (Kemp et al 2010). As with those papers, this compilation is intended to encourage our fellow ancient mariners to record their experiences of navigating ships in the middle years of the 20 th century.…”