I am pleased to hear that you are making progress.
Please visit the excellent website, ConvoyWeb at http://convoyweb.org.uk/hague/index.html. This website contains information on the convoys in which various ships sailed, their originating and destination ports, applicable dates and sometimes a brief description of the cargo a ship carried or any unusual event involving a given ship. There will be no information about the crew. By knowing when your grandfather was aboard each ship you can cross-reference the whereabouts of the ship at those times.
At the above web page, do a "SHIP SEARCH" for each ship; be careful about spellings although even a partial name is enough to find the ship, if it is in the database. If the ship is in the ConvoyWeb database, you will get a list of the convoys in which the ship sailed along with the month and year of the convoy. Click on the number of each convoy for details about the convoy. Additionally, at the bottom of the list of convoys you will see "To continue the search for other voyages of [ship's name], click here." Following that link will give a comprehensive listing, in chronological order, of the whereabouts of the ship throughout the war, including any voyages she made independently (i.e., not in convoy and unaccompanied by other ships). This latter list is actually better to use since it is comprehensive for all ship movements and is in date order. The list of convoys is in order by type of convoy.
In my experience, ConvoyWeb is quite good for ship movements in the Atlantic and Mediterranean, somewhat hit-or-miss on movements in the Caribbean, and rather sketchy for ship movements in the Pacific.
Ron Carlson, Webmaster
Armed Guard / Merchant Marine website