As a submariner stationed on Halifax Nova Scotia Canada in the early 1960's, we often went under the ice in the Cabot Straits looking for polynya's.  See my page < Bits and pieces Volume V - Section 6 The Mutiny > for details.

To find, and thereafter use the polynya's, we were modified in two ways.  Firstly, we were fitted with an "upward looking echo sounder {our standard fit was a conventional "downward looking echo sounder to ascertain the depth below us to the sea bed} and secondly with a strengthened  fin which we used as a battering ram to break through the ice in the polynya to gain access to the surface.

It used to be one of my many jobs in the submarine to record the readings from both sounders which at that time was a boring chore.  However, since those days, I have taken an interest in the 'machines' we used, and I am also fascinated with the Hood [I am a member of that Association] and her equipment per se.  On my web site you will find several pieces about the Hood's electrical fit/gunnery fit and her radio communications fit.  One of her pieces would have been a sounding machine called the "KELVITE" and she would have had the motorised version.  If you look to my page http://www.godfreydykes.info/HMS HOODS ELECTRICAL EQUIPMENT.pdf and scroll down to the ship] with the word BANG astern of her, just below that point you will see a PDF.  Click on it to open and then scroll down the list to page 127, where you will find all details of the KELVIN [Kelvite] sounding machine electrical motor requirements.

This Mk 4 machine, introduced into the navy from about 1930 onwards took over from the previous Mk's which in turn had seen out the laborious job of swinging-the-lead to take soundings, and continued to be used with various modifications until relieved by the echo sounder, which for some warships, meant right into the 1950's.  Look here at research into echo sounding conducted in the 1920's ECHO SOUNDING EXPERIMENTS IN THE 1920's.htm

In the following PDF's I have published the details of the hand version and the motorised version, the highly successful Mk4 version.

Anorak ? - possibly, but interesting nonetheless.  Please note that the following three PDF's are quite large. KELVITE SOUNDING MACHINE - PART 1.pdf.  The Kelvite Sounding Machine - Part 2.pdf.    The Kelvite Sounding Machine - Part 3.pdf.  This file I have made from the 1907 Edwardian Seamanship Manual 1907 SEAMANSHIP MANUAL SOUNDING TECHNIQUES.pdf

Safe journey and safe navigation!