I suggest you do a "Ship Search" on the names of both ships at ConvoyWeb ( http://convoyweb.org.uk/hague/index.html). ConvoyWeb lists 26 convoys for WILLIAM A. RICHARDSON, and 17 convoys for WILLIAM S. HALSTED (note correct spelling). Also search WarSailors.com at https://www.warsailors.com/search.html, although that site will likely have only Atlantic and Mediterranean convoys.
ConvoyWeb overall is more comprehensive than WarSailors although WarSailors occasionally has more detail on a specific convoy or even a specific ship.
By matching convoy dates with the dates your father was aboard each ship you can determine his whereabouts with some accuracy, if only "at sea."
Ron Carlson, Webmaster
Armed Guard / Merchant Marine website