Two good books on WW1 Convoy are 'Business in Great Waters' by John Terraine and 'Convoy: The Defence of Sea Trade 1890 - 1990' by Johan Winton.
An interesting line in Terrain's book on the WW1 A/S effort from Admiral Jameson
' The German Submarines......They had been foiled rather than defeated'
Convoy wasn't a total answer, you have just got to look at the loss of the liner Justica, despite having IIRC, 8 destroyesr as her escort, she was still sunk.
You need effective ways of detecting the U-boat and then effective ways of destroying it and they weren't around until 1917/1918. Convoy would reduce losses but it wont eliminate them.
I'm not sure how the formatting will work but the figures suggest Admiral Jameson was correct in his assessment, this is losses as listed in Terrain's book.
August 1914 – December 1914 312,0672 tons Average 62,534 tons/month
January 1915 – June 1915 440,163 tons Average 73,336 tons/month
July 1915 – December 1915 812,108 tons Average 135,351 tons/month
January 1916 – June 1916 795,570 tons Average 132,595 tons/month
July 1916 – December 1917 1,532,726 tons Average 255,287 tons/month
January 1917 – June 1917 3,667,531 tons Average 611,255 tons/month
July 1917 – December 1917 2,568,347 tons Average 428,057 tons/month
January 1918 – June 1918 1,798,038 tons Average 299,673 tons/month
July 1918 – November 1918 868,904 tons Average 173,780 tons/month
The figures for late 1918 despite convoy and everything learned to date are still bad.
Allied and Neutral Tonnage sunk by submarines in World War IMonth19141915191619171918January47,98181,259368,521306,658February59,921117,547540,006318,957March80,775167,097593,841342,597April55,725191,667881,027278,719May120,058129,175596,629295,520June131,428108,855687,507255,587July109,640118,215557,988260,967August62,767185,866162,744511,730283,815September98,378151,884230,460351,748187,881October87,91788,534353,660458,558118,559November19,413153,043311,508289,21217,682December44,197123,141355,139399,212Total312,6721,307,9962,327,3266,235,8782,666,942
Grand Total 12,850,814 gross tons
Convoys came in in April 1917 as a trial when sinkings were at their height and the sinkings began to go down after that although the January to June figure covers 6 months without and 6 months with. They were officially introduced in September 1917 and sinkins begin to dramatically fall as escorts get used to hunting u-boats. Before this sinkings were rising probably due to the reintroduction of unrestricted submartine warfare.
Another factor was the use of airships which were valuable for reconniasence purposes. Convoys were resisted by the First Sea Lord Jellicoe who was eventually removed for defeatist attitudes. The effect of their introduction earlier might have encouraged unrestricted submarine warfare but if it was a foregone conclusion I am surprised Chruchill didn't try it when he was First Lord of the Admiralty? as one of the effects of Q ships was to encourage attacking without warning and it was used as justifaction as convoys would have b een.
An early intervention by America would have given Britain a lot more escorts. Convoays came in AFTER America joined, the availability of escorts may have been a factor
Aquestion to answer is what would have happened if Admiral King had introduced convoys off the America seaboard earlier in World War 11?