60 DISCOVERY REPORTS 



of the strait and the Trinity Peninsula coast were blocked throughout nearly the whole 

 season. Thus the ice conditions inside the Bransfield Strait vary very considerably from 

 year to year. 



The pack-ice outside the strait on the northern side of the South Shetland Islands 

 usually exists in a semicircular shape running north-east and south-west of these islands. 

 This ice is usually still present until after the Bransfield Strait is either navigable or free 

 from much hindrance. 



When a succession of north-easterly winds is absent, or when no fresh accumulation 

 of pack-ice is formed at the north-east end of the Bransfield Strait, the speed with which 

 the ice moves out of the strait is remarkable. Thus on November 7 1923 the Bransfield 

 Strait was reported full of thick pack-ice and large icebergs, whilst on November 16 

 only scattered ice remained which was no hindrance to navigation. 



The whaling fleet has usually been able to work in and south of the de Gerlache Strait 

 in January. 



The Antarctic Pilot (1930), in giving the opinion of the whaling captains, states 

 " . . .during November and the first half of December only a narrow strip of ice-free 

 water exists from Martins Head [King George Island] to Deception Island, enabling 

 vessels to pass through Nelson Strait and make Admiralty Bay ; but in some seasons the 

 bay itself is shut off by ice extending from Telefon Rocks [King George Island], in which 

 case Port Foster, Deception Island, may be reached instead. This ice is sea ice and bergs 

 drifting east-north-east close in to the south side of King George Island and thence to 

 the south side of Elephant Island. ... All this ice appears to come from outside Palmer 

 Archipelago. The main pack comes eastward, past the south side of Deception Island, 

 but a little may pass northward of the island" (p. 71). "The general current in de 

 Gerlache Strait is to the north-east. Ice from de Gerlache Strait goes on north-eastwards 

 through Orleans Channel, where many bergs are stranded. . . " (p. 84). 



Two main current features are to be seen in the Bransfield Strait ; part of the water 

 from the Bellingshausen Sea enters the strait between the islands of Snow, Smith and 

 Low and flows both north and south of Deception Island, where it makes a characteristic 

 bend to the south-east before returning to the north-west, and then flows as a north-east 

 set along the southern shores of the South Shetland Islands. The second great current 

 movement comes from the Weddell Sea, bringing a large amount of cold dense water 

 round Joinville Island which then spreads across the north-eastern end of the strait and 

 down the coast of Trinity Peninsula. 



The positions of some of the stations worked by the research ships have obviously 

 been affected by these currents, which, however, are variable in strength. Thus during 

 the time the R.R.S. 'Discovery II' was in the Bransfield Strait in April 1930 an 

 allowance of 1-2 knots was made for the speed of the north-east flowing current close to 

 the South Shetland Islands, during a passage across the strait from south-east to north- 

 west. The result was that the final position of the ship was too much to the south-west 

 and no allowance need have been made at all. A very considerable belt of pack-ice had 

 been observed to the east and this may have had the effect of slowing down very greatly 



