Measuring depth at sea in the early nineteenth century was a complicated affair. A single sounding event could take many hours and required the ship’s position to be accurately estimated throughout the duration of the investigation. Bad weather moved ships off course and curtailed sounding events in mid-flow. Overestimations were commonplace when underwater currents dragged the lead horizontally through the water, whilst the crewmen on board ship continued to pay out the line. To add to these difficulties was the issue of instrumentation: no one sounding device was universally agreed upon to provide reliable results. As a consequence the representation of the deep sea changed dramatically as the nineteenth century progressed. Whilst much has been written of Maury’s first bathymetric maps, this paper focuses on the lesser explored area of depth recording during the Arctic expeditions of Captains John Ross, William Parry and John Franklin. Testing of new scientific equipment was also one of the key goals of early nineteenth century polar expeditions organised and funded by the British Admiralty. I suggest in this thesis that the reason one piece of sounding equipment became favoured over another was its ease of use by the crew on board ship. I go on to consider Bruno Latour’s idea of transcriptions, and argue that rather than using sounding maps at this time as immutable mobiles, the expedition captains were forced to perform new soundings all the time, and construct new maps of the polar seas as they experienced them. This thesis draws on Actor-Network theory to suggest soundings in the Polar Regions at this time were part of a wider of network of scientific investigation and navigation, and that no network of technology, men and representations were constructed strong enough to withstand the dissociating forces of the polar seas and adverse weather at this point in time.