There is a William F Boyle who appears in Ancestry's U.S. WWII Navy Muster Rolls, 1938 thru to 1949.
It reads:-
William F Boyle (6146919) - F/Sgt USA - Ship Antaeus - Ship Number or Designation 21 -Transportation to the US - Muster Date 29th April 1943.
Don't know if this is your guy but this is the first entry that may be relevant. There are also quite a number of other military entries re this name (to many to relate). May be worth your further investiation or subscribing to Ancestry to include the US. Hope this helps......& Rgds.